CL3.1.1 | Regional to local climate change, processes, impacts, and extremes
EDI
Regional to local climate change, processes, impacts, and extremes
Co-organized by AS1
Convener: Merja Tölle | Co-conveners: Lorenzo Sangelantoni, Emanuela Pichelli, Douglas Maraun, Puxi LiECSECS
Orals
| Tue, 16 Apr, 08:30–12:30 (CEST), 14:00–15:45 (CEST)
 
Room 0.14
Posters on site
| Attendance Wed, 17 Apr, 10:45–12:30 (CEST) | Display Wed, 17 Apr, 08:30–12:30
 
Hall X5
Orals |
Tue, 08:30
Wed, 10:45
This session explores climate change, extremes, processes and their impacts at regional to local scales, and the tools employed to investigate these phenomena. In particular, we welcome submissions advancing the state-of-the-art in the development and application of high-resolution models (convection-permitting, grid spacing ≤ 4 km) and high-resolution sub-daily data sets. This also includes high-resolution data sets for the land-surface including urban areas, hydrology, vegetation or similar, and their impacts on local-scale climate change and extremes.

The session aims to bring together, amongst others, numerical modellers, the observational community and CORDEX-FPS participants, with the aim of advancing understanding of the aforementioned topics. Of particular interest are new insights which are revealed through high-spatiotemporal-resolution modelling or data sets. For example: convective extremes, physical mechanisms, fine-scale and feedback processes, differences in climate change signal, scale-dependency of extremes, interactions across scales and land-atmosphere interactions. Further, we welcome studies that explore local scale climate change in a variety of contexts whether they be past, present or future change. Studies that move towards an earth system approach – through incorporating coupled oceans, hydrology or vegetation – are especially encouraged.

Additional topics include, though are not limited to:
-- Mesoscale convective systems and medicanes
-- Event-based case studies (including surrogate climate change experiments or attribution)
-- Approaches for quantifying uncertainty at high resolutions including multi-model ensemble and combined dynamical-statistical approaches such as emulators
-- High-resolution winds and their impacts
-- Convection, energy balance and hydrological cycle including vegetation and cities
-- Model setup and parametrization, including sensitivity to resolution, land surface and dynamics
-- Tropical convection and convective processes at local to regional scale
-- Model evaluation and new evaluation metrics/methods
-- Physical understanding of added value over coarser models
-- Severe storms including supercell thunderstorms and hailstorms
-- The roles of natural and internal variability

Orals: Tue, 16 Apr | Room 0.14

The oral presentations are given in a hybrid format supported by a Zoom meeting featuring on-site and virtual presentations. The button to access the Zoom meeting appears just before the time block starts.
Chairpersons: Merja Tölle, Puxi Li, Lorenzo Sangelantoni
08:30–08:35
08:35–08:45
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EGU24-8279
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CL3.1.1
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ECS
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On-site presentation
James Ciarlo, Erika Coppola, Aaron Micallef, and David Mifsud

Arthropods play vital roles in the ecosystem (e.g., pollinators, decomposers, biological pest control), and thus can act as indicators of ecosystem integrity. The state of these ecosystems is sensitive to variations in climate conditions, especially on small islands. The Circum-Sicilian islands are a chain of small islands around Sicily in the central Mediterranean. With the use of Convection permitting simulations, many of these islands can finally be adequately resolved. The objective of the project PALEOSIM (PALEOclimate modelling of Small Islands in the Mediterranean and possible impacts on arthropod habitats) is to study climate impacts on the habitats of arthropods (mainly insects) in the Circum-Sicilian islands. To achieve this, RegCM5 is driven by CMIP6 and PMIP4 data for a 3 km region covering the west and central Mediterranean.

Climate indices from the simulations have been used to assess the ecological niche of select arthropod species and hence determine how these conditions have changed across different time scales. The data used to drive RegCM5 allows for the study of time slices across several scenarios, which include: the last glacial maximum, mid-Holocene, ~1000 CE, ~1850 CE, ~1995 CE (a historical baseline), and Global Warming Levels of 1.5, 2, and 3 °C. This analysis reveals how some species are especially sensitive to changes in climate conditions, and the significant threat of the current climate crisis.

How to cite: Ciarlo, J., Coppola, E., Micallef, A., and Mifsud, D.: Climate-induced variations in arthropod habitats of the Circum-Sicilian islands according to convection permitting simulations of the Mediterranean driven by CMIP6 and PMIP4 data, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8279, https://doi.org/10.5194/egusphere-egu24-8279, 2024.

08:45–08:55
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EGU24-11710
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CL3.1.1
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ECS
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On-site presentation
Lucas Fery and Davide Faranda

Derechos are severe convective storms known for producing widespread damaging winds. While less frequent than in the United States of America (USA), derechos also occur in Europe. The notable European event on 18 August 2022 exhibited gusts exceeding 200 km h-1, spanning 1500 km in 12 hours. This study presents a first climatology of warm-season derechos in France, identifying thirty-eight (38) events between 2000 and 2022. Similar to Germany, derechos in France are associated with a southwesterly circulation and display comparable frequencies. While a suggestive trend of higher late-season frequency and a potential larger proportion of low-intensity events in France are observed, caution is warranted due to the lack of statistical significance arising from a relatively small sample size. The study also examines synoptic and environmental changes linked with analogues of the 500 hPa geopotential height patterns associated with past warm-season derechos, comparing analogues from a relatively distant past (1950–1980) with a recent period (1992–2022). For most events, a notable increase in convective available potential energy (CAPE) is observed, consistent with Mediterranean trends. However, there is no consistent change in 0–6 km vertical wind shear in the recent period. These environmental shifts align with higher near-surface temperatures, altered mid-level atmospheric flow patterns, and often, increased rainfall. The role of anthropogenic climate change in these changes remains uncertain, given potential influences of natural variability factors such as the El Niño Southern Oscillation (ENSO) or the Atlantic Multidecadal Oscillation (AMO).

How to cite: Fery, L. and Faranda, D.: Analyzing 23 years of warm-season derechos in France: a climatology and investigation of synoptic and environmental changes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11710, https://doi.org/10.5194/egusphere-egu24-11710, 2024.

08:55–09:05
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EGU24-672
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CL3.1.1
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ECS
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On-site presentation
Noah Breuninger and Kirsten Warrach-Sagi

In Europe, extreme weather events are expected to increase noticeably in frequency, duration, and intensity with the continued warming of the planet's climate. Land-atmosphere feedbacks have been shown to play an important role in the exacerbation of events such as heat waves and droughts. Due to the important role of convective events in local weather an improved understanding of the role that land-atmosphere feedback plays in the development of convection initiation is required.

The heated condensation framework (HCF) enables the quantification of land-atmosphere coupling strength and local convection events in dependence of the temperature and moisture profiles from the ground to the planetary boundary layer height. The HCF is applied to the hourly data from the Weather Research and Forecasting (WRF) model application of the University of Hohenheim (UHOH) within the decadal km-scale regional climate simulations within CORDEX-FPS convection.

The analysis reveals the Po-Valley area as a hotspot of land-atmosphere coupling-induced local convection initiation in central Europe. Further strong wet and dry soil anomalies impact the number of local convection initiation events throughout the studied domain.

How to cite: Breuninger, N. and Warrach-Sagi, K.: Land-atmosphere coupling induced local moist convection initiation in central Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-672, https://doi.org/10.5194/egusphere-egu24-672, 2024.

09:05–09:15
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EGU24-10599
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CL3.1.1
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ECS
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On-site presentation
Ana Fernandez-Garza, Eric Gielen, Manuel Pulido-Velazquez, Hector Macian-Sorribes, Adria Rubio-Martin, and Dariana Avila-Velasquez

Heatwaves have emerged as an increasingly recurrent extreme meteorological event, in the Mediterranean region and throughout Europe, during the summer. This is attributable to shifts in the distribution and magnitude of temperatures. In particular, the Comunitat Valenciana a region in Spain experienced the last summer its highest temperature, registering a 1.6ºC increase in the monthly average temperature compared to the reference period (1991-2020). On August 10, the historical record was exceeded by 3.4ºC, with temperatures exceeding 40ºC in more than 50% of the territory as reported by the Spanish Meteorological Agency (AEMET). During this climatic event, the Mortality Monitoring (MoMo) system reported a substantial spike in excess deaths, reaching 1,990 in August. This figure significantly exceeded the preceding month’s tally of 686 fatalities and the subsequent month’s count of 186 deaths. This concentration of mortality in the hottest month underscores the severity of the impact.

The analysis of heatwaves is crucial to provide scientific support for the necessary formulation of inform adequate public policies. Additionally, it enables the population to undertake necessary actions to mitigate the adverse effects of high temperatures.

In a context of increasing temperatures due to climate change, foreseeing its future evolution would provide valuable information for better preparedness. The present research analyses future heatwaves and trends in the city of Valencia, Spain. Future temperatures refer to five bias adjusted CMIP6 (Coupled Model Intercomparison Project Phase 6) climate change models across four different scenarios: historical (1979 to 2014), SSP126, SSP370 and SSP585 (2015-2100). Model suitability is evaluated comparing historical runs with reference data from W5E5-ERA5Land. Afterwards, an analysis of future heatwaves is conducted, using the operational definition of heatwave from Spain: periods of at least three consecutive days where maximum temperature exceeds a critical threshold set by each municipality, which in Valencia refers to the 90th percentile of maximum temperatures for the historical period.

For each detected heatwave the selected indicators are: the number, frequency, duration, intensity, amplitude, and risk level associated with these climatic events. Our analysis evaluates how the number of heatwaves vary, as well as to understand the behaviour of heatwaves in Valencia to determine how the risk might evolve in future contexts, and in a future generating a predictive model providing information on their spatial distribution, intensity, duration and severity.

Acknowledgements:

This study has received funding from the: “THE HUT project” (The Human-Tech Nexus – Building a Safe Haven to cope with Climate Extremes), under the European Union’s horizon research and innovation programme (GA No. 101073957).

How to cite: Fernandez-Garza, A., Gielen, E., Pulido-Velazquez, M., Macian-Sorribes, H., Rubio-Martin, A., and Avila-Velasquez, D.: Heatwave analysis over the city of Valencia (Spain) for past and future climate change models and scenarios, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10599, https://doi.org/10.5194/egusphere-egu24-10599, 2024.

09:15–09:25
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EGU24-16691
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CL3.1.1
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Highlight
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On-site presentation
Contributions of urbanization to a mega-heatwave and the health impacts in the Yangtze River Delta Metropolitan
(withdrawn)
Jiacan Yuan, Siyang He, Xiangyu Ao, and Chen Liang
09:25–09:35
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EGU24-6792
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CL3.1.1
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On-site presentation
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Kwok Pan Chun, Thanti Octavianti, Hristos Tyralis, Georgia Papacharalampous, Rosmeri Porfirio da Rocha, Emir Toker, Yasemin Ezber, Luminita Danaila, Kate Halladay, and Ron Kahana

Increasing spatial resolution to kilometre scales allows the deactivation of deep convection parameterisation schemes. As a result of various global initiatives for the next generation of climate studies, continental convection-permitting model (CPM) simulations are now accessible. Nonstationary local extremes, like heatwaves and intense precipitation, are probabilistically linked to regional circulation through scaling relationships. However, these relationships have not been extensively explored in the new simulations available in the early 2020s. Hourly time series data were extracted from the UK Climate Science for Service Partnership (CSSP) and the US South America Affinity Group (SAAG) CPM simulations to compare extreme characteristics of precipitation and temperature for 39 stations in a region of São Paulo, Brazil. Compared to reanalysis and satellite data, which exhibit lower variance in hourly time series, these two sets of CPM simulations have precipitation that is more similar to station observations than the ERA5 data and the Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement (IMERG) data.

The cross-correlation structures of the time series are investigated to quantify temporal dependence and reveal patterns between temperature and precipitation at an hourly timescale. Within a higher-dimensional probability space for joint risk, the cross-correlation structures between temperature and precipitation at different lags demonstrate the "memory" of these variables, indicating the influence of past values on future behaviour across multiple time points. Their forecasting power for these two variable based on each other is also explored to offer insights into the physical processes within the evolving simulated dynamic system.

Overall, the results underscore the added value of convection-permitting models in providing more realistic simulations of local dynamics of extremes. The identified cross-correlation structures from the CPMs are valuable for exploring opportunities to design AI engines based on weather generator algorithms that use stochastic differential equations. Using CPM simulations, these weather generators can be employed to develop AI approaches for rapid decision support tools aimed at stakeholders facing extreme weather events related to compound risks of temperature and precipitation.

How to cite: Chun, K. P., Octavianti, T., Tyralis, H., Papacharalampous, G., da Rocha, R. P., Toker, E., Ezber, Y., Danaila, L., Halladay, K., and Kahana, R.: Exploring Continental Convection-Permitting Model Simulations for South America: Cross-correlation Dynamics between precipitation and temperature time series at São Paulo, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6792, https://doi.org/10.5194/egusphere-egu24-6792, 2024.

09:35–09:45
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EGU24-12016
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CL3.1.1
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ECS
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Highlight
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On-site presentation
Sergi Ventura, Josep Ramon Miró, Ricard Segura-Barrero, Fei Chen, Alberto Martilli, Changhai Liu, Kyoko Ikeda, and Gara Villalba

Given that cities concentrate more than half of the global population, it becomes crucial to assess the potential impacts of future climate change on cities. This study employs the Pseudo Global Warming (PGW) methodology to replicate recent heatwave (HW) episodes in the Metropolitan Area of Barcelona (AMB) under projected climate conditions until the year 2100. Initially, we identify all the HW events in the AMB over the past three decades (1991-2020) and simulate these HWs using the high-resolution Weather and Research Forecasting model (WRF) with the urban parameterizations BEP+BEM. 

Subsequently, the HWs observed in the last 30 years are replicated under mid-century (2041-2070) and end-century (2071-2100) climate conditions based on the SSP370 scenario. This scenario considers a future where greenhouse gas emissions and temperatures consistently rise, reflecting current climatic trends and geopolitical realities, including regional conflicts. Anticipated CO2 emissions are forecasted to nearly double from present levels by the year 2100.

The contrast between recent and future HWs is examined not only in terms of temperature and relative humidity but also concerning the synoptic patterns responsible for generating HW conditions. The findings reveal a potential increase in geopotential height by up to 100 geopotential meters (gpm) by the end of the century, reaching values of up to 6050 gpm. Average maximum 2-m air temperatures are projected to rise by 2.5°C during the mid-century and 4.2°C by the end of the century. The most significant temperature anomalies (deviations from the mean temperature) are associated with persistent and stable synoptic patterns, which are projected to increase the most in frequency and intensity. The findings on relative humidity reveal a general decrease over the AMB, with a peak value of -16.2% in the west of the domain during the PGW-END.

How to cite: Ventura, S., Miró, J. R., Segura-Barrero, R., Chen, F., Martilli, A., Liu, C., Ikeda, K., and Villalba, G.: Determining the intensity of future heatwave episodes at urban scales: the case study of the Metropolitan Area of Barcelona, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12016, https://doi.org/10.5194/egusphere-egu24-12016, 2024.

09:45–09:55
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EGU24-11048
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CL3.1.1
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ECS
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On-site presentation
Benjamin Le Roy and Diana Rechid

Extreme weather and climate events such as heat waves, droughts or heavy precipitation are already impacting urban areas worldwide, and such extremes are expected to become more frequent and/or severe with climate change. For vulnerability assessment and climate resilient urban planning, local decision-makers and stakeholders need high-resolution climate information that is tailored to their needs according to different geographical contexts (e.g. through the representation of mountainous areas, coastal lines or city characteristics). They also need information on the appropriate time scale, from specific events of a few days to decade-long statistics. Today, regional climate information often comes from global climate models that are downscaled to the local scale using statistical tools or regional climate models (RCMs) such as those used in the CORDEX initiative.

Longterm RCM simulations achieve horizontal resolutions of the order of ten kilometers and offer added value in certain respects compared with their global counterparts, but remain insufficient in certain specific geographical contexts such as the representation of cities, highly heterogeneous mountainous areas or along coastlines. The latest generation of RCMs, known as Convection Permitting Regional Climate Models (CPRCMs), now reach a spatial resolution of a few kilometers and can better represent heterogeneous land surfaces, with the potential offering a new quality of climate information better suited to local applications.

Here, we compare some evaluation simulations (e.g. driven by reanalysis) carried out as part of the EURO-CORDEX initiative (12,5 km RCM) and the CORDEX Flagship Pilot Study on Convection (3 km CPRCM) over the period 2000-2009. We analyze their ability to represent the urban climate of different European cities and the differences resulting from choices in urban parameterizations, land cover representation approaches (dominant coverage or fractional approaches) and land cover databases. We show that:

  • For most European cities, RCM simulations have a too coarse resolution; for example, for all coastal cities, the points that should be considered urban are mainly covered by water.

  • CPRCM simulations enable these areas to be better represented thanks to the increased resolution, but there are significant differences depending on how the different land covers are represented in a grid cell and how urban areas are simulated.

  • Depending on the meteorological variables of interest, some of the simpler urban parameterizations (altered slab) give results that are relatively close to the more sophisticated ones (multi-layer urban canyon).

  • While the increased complexity of CPRCM simulations enables urban climate to be better represented, it also increases the differences between simulations and makes it more difficult to quantify uncertainties and synthesize results into a general assessment (which is often needed by decision-makers) underlining the growing need to use ensembles of climate models for impact assessment.

How to cite: Le Roy, B. and Rechid, D.: Added values and uncertainties of convection permitting regional climate model simulations for urban impact studies over Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11048, https://doi.org/10.5194/egusphere-egu24-11048, 2024.

09:55–10:10
Coffee break
Chairpersons: Merja Tölle, Lorenzo Sangelantoni, Puxi Li
10:45–11:15
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EGU24-10431
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CL3.1.1
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solicited
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On-site presentation
Giorgia Fosser and Simona Bordoni

The past 10 years of research proved that regional convection-permitting models (RCPMs) more realistically represent sub-daily statistics and extremes compared to GCMs and RCMs thanks to the possibility to switch off the parameterisation of convection at this resolution. Now, thanks to recent computational advancements, GCMs are approaching convection-permitting resolution (GCPM), but little is known on their performance at climatological scale over Europe.

Here we compare two 5-year GCPM simulations performed with IFS and ICON, respectively at 9 and 5km, within the NextGEMs project against the multi-model RCPM ensemble at circa 3 km run under the CORDEX Flagship Pilot project on Convective Phenomena over Europe and the Mediterranean (FPS Convection). The analysis focuses on the representation of sub-daily precipitation characteristics between GCPMs in comparison with the RCPM ensemble and several regional observational datasets over the greater Alpine region. In additional, the impact of a higher resolution (5km instead of 25km) of the ocean model is investigated thanks to an additional GCPM run. The natural variability of the GCPMs is evaluated with a bootstrapping approach and put in relation with the total and model uncertainty of the RCPM ensemble.  

Having GCMs that realistically represent the large-scale dynamics as well as the local scale process would be a crucial step forward and provide further confidence on the climate projections and support the Destination Earth project of the European Community.

How to cite: Fosser, G. and Bordoni, S.: Lessons learnt on convection-permitting models and their uncertainty at both global and regional scale , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10431, https://doi.org/10.5194/egusphere-egu24-10431, 2024.

11:15–11:30
11:30–11:40
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EGU24-10660
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CL3.1.1
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Highlight
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On-site presentation
Geert Lenderink, Hylke de Vries, and Erik van Meijgaard

Convection permitting climate models (CPMs) display much improved present-day rainfall statistics at local scales as compared to common regional and global climate models. Yet, because CPMs are computationally very demanding, runs are short — typically covering 10 to 20 years  only  —  which makes it hard to distinguish the changes due to global warming from the noise due to internal variability. In addition, runs cover a limited set of changes at larger scales as only few global climate models have been downscaled so far. This challenges the representativeness of the results. Here, we discus these issues within the context of the production of the Dutch climate scenarios issued in fall 2023. We use spatial pooling of information to improve signal to noise. To produce scenarios for local rainfall extremes, we combined information from the CPMs with information from CMIP6 and one RCM (RACMO) using a simple scaling framework. From the CPMs we derived sensitivities of changes in rainfall intensity to surface dew point temperature change. By using spatial pooling and by taking out rain frequency change (using wet conditional statistics) a reasonable collapse of the data of 7 CPM simulations could be obtained, with typical dependencies between 1 and 2 times the Clausius Clapeyron relation. The change in rain frequency and the dew point temperature are derived from a  set of RACMO simulations using pseudo-global warming perturbations derived from CMIP6 combined with a simple perturbed physics method. With these RACMO simulations we covered a range in large-scale conditions compatible with CMIP6.  Subsequently, rain intensity change and frequency change are combined using a transformation of the observed rainfall distribution.  In this way, we could produce a set of climate scenarios for daily and hourly precipitation extremes covering a wide range in global change conditions. Besides these changing rainfall statistics, we also analyzed the spatial temporal characteristics of showers in order to investigate whether showers become larger in scale in the future climate.

How to cite: Lenderink, G., de Vries, H., and van Meijgaard, E.: Combining convection permitting modeling results with CMIP6 global climate model results to produce scenarios for local precipitation extremes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10660, https://doi.org/10.5194/egusphere-egu24-10660, 2024.

11:40–11:50
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EGU24-3009
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CL3.1.1
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ECS
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On-site presentation
Wei Sun, Jian Li, Rucong Yu, Nina Li, and Yi Zhang

Understanding the responses of precipitation extremes to global climate change remains limited owing to their poor representations in models and complicated interactions with multi-scale systems. Here we take the record-breaking precipitation over China in 2021 as an example, and study its changes under three different climate scenarios through a developed pseudo-global-warming (PGW) experimental framework with 60–3 km variable-resolution global ensemble modeling. Compared to the present cli- mate, the precipitation extreme under a warmer (cooler) climate increased (decreased) in intensity, cov- erage, and total amount at a range of 24.3%–37.8% (18.7%–56.1%). With the help of the proposed PGW experimental framework, we further reveal the impacts of the multi-scale system interactions in climate change on the precipitation extreme. Under the warmer climate, large-scale water vapor transport con- verged from double typhoons and the subtropical high marched into central China, enhancing the con- vective energy and instability on the leading edge of the transport belt. As a result, the mesoscale convective system (MCS) that directly contributed to the precipitation extreme became stronger than that in the present climate. On the contrary, the cooler climate displayed opposite changing characteris- tics relative to the warmer climate, ranging from the large-scale systems to local environments and to the MCS. In summary, our study provides a promising approach to scientifically assess the response of pre- cipitation extremes to climate change, making it feasible to perform ensemble simulations while inves- tigating the multi-scale system interactions over the globe.

How to cite: Sun, W., Li, J., Yu, R., Li, N., and Zhang, Y.: Exploring changes of precipitation extremes under climate change through global variable-resolution modeling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3009, https://doi.org/10.5194/egusphere-egu24-3009, 2024.

11:50–12:00
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EGU24-11130
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CL3.1.1
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ECS
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Highlight
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On-site presentation
Iris Thurnherr, Ruoyi Cui, Patricio Velasquez, Killian Brennan, Lena Wilhelm, Heini Wernli, Christian R. Steger, and Christoph Schär

Thunderstorm-related severe weather, in particular hail, causes extensive damage to life and infrastructure in the Alpine region. However, changes in hail impact due to a warmer climate are still not fully understood. In the scClim project, convection-permitting regional climate simulations over Europe using the model COSMO with a ~2.2 km horizontal resolution have been conducted for present-day climate conditions (2011-2021) and a climate scenario with a 3°C global warming using a pseudo-global-warming approach. ERA5 reanalyses were used as boundary conditions and a CMIP6 simulation (MPI-ESM1-2-HR) to infer the large-scale climate-change signal. The integrated online diagnostic HAILCAST is used to calculate maximum hail size. The simulations provide total precipitation and maximum hail size estimates every 5 minutes, which allows for hail cell tracking in the climate simulations and the analysis of hail events in a warmer climate. Validation of the present-day simulation against observations of temperature, precipitation and hail shows an overall good model performance. For hail in particular, radar-based, station-based and crowd-sourced observations have been used to assess the model performance in simulating hail on spatial, diurnal and seasonal scales. The validation outcome encourages further study of the climate signal of hail as simulated with the pseudo-global-warming approach. We will show projected changes in the spatial distribution and seasonal cycle of hail over Europe as well as changes in lifetime, storm area and location of hail cells due to a 3°C global warming.

How to cite: Thurnherr, I., Cui, R., Velasquez, P., Brennan, K., Wilhelm, L., Wernli, H., Steger, C. R., and Schär, C.: How does 3°C global warming affect hail over Europe?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11130, https://doi.org/10.5194/egusphere-egu24-11130, 2024.

12:00–12:10
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EGU24-11157
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CL3.1.1
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ECS
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Highlight
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On-site presentation
Nathalia Correa Sánchez, Eleonora Dallan, Francesco Marra, Giorgia Fosser, and Marco Borga

Past studies have shown that in orographically complex terrain, observed extreme precipitation intensity is impacted by elevation in different ways at different durations. Convection-permitting climate models (CPMs) are receiving increasing attention thanks to the more realistic representation of extreme sub-daily precipitation compared to coarser climate models. Two almost still unexplored themes concern: i) CPMs' ability to represent the observed relationship between precipitation and topography and ii) how the model ensemble uncertainty depends on elevation. To address these questions, we evaluate sub-daily extreme precipitation from an ensemble of eight CPM members (reanalysis-driven simulations) on topographically diverse terrains. We use observed data from rain gauges as benchmark. The analysis is conducted over the Eastern Italian Alps, where a strong relationship between precipitation sub-daily extremes and topography is observed (Dallan et al., 2023). We apply a non-asymptotic statistical approach (Simplified Metastatistical Extreme Value, SMEV) to estimate extreme precipitation return levels and assess their intra-model and inter-model uncertainties using a bootstrapped samples method. It is shown that the ensemble mean describes in a realistic way the precipitation extremes, with fractional standard errors of the mean-over-the-ensemble return levels ranging between 0,16 (24 hrs duration, 2 yrs return time) to 0,41 (1 hr duration, 100 yrs return time). We found that, compared to rain gauges, CPMs systematically underestimate extreme return levels in lowlands, whereas overestimate them at higher altitudes. Nevertheless, the CPMs can capture the relationship between rain depth and elevation, which is particularly important for 1-3 hrs duration. While the intra-model uncertainty decreases systematically with elevation at all durations, a more complex behaviour is observed for both inter-model and total uncertainty. These findings help to characterize the impact of elevation on the ensemble of CPM simulations, which is particularly required for the applications of these simulations for adaptation to future flood risk.

REFERENCES
Dallan, E., Marra, F., Fosser, G., Marani, M., Formetta, G., Schär, C., & Borga, M. (2023). ID56. How well does a convection-permitting regional climate model represent the reverse orographic effect of extreme hourly precipitation? Hydrology and Earth System Sciences, 27(5), 1133–1149. https://doi.org/10.5194/hess-27-1133-2023.

How to cite: Correa Sánchez, N., Dallan, E., Marra, F., Fosser, G., and Borga, M.: Evaluating sub-daily extreme precipitation from an ensemble of convection-permitting simulations: the role of topography., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11157, https://doi.org/10.5194/egusphere-egu24-11157, 2024.

12:10–12:20
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EGU24-16029
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CL3.1.1
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ECS
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Highlight
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On-site presentation
Kun Xie, Lu Li, Stefan Sobolowski, Hua Chen, and Chong-Yu Xu

Convection-permitting climate models (CPMs) have demonstrated enhanced capability in capturing extreme precipitation compared to convection-parameterization models. Despite this, a comprehensive understanding of their added values in daily or sub-daily extremes, especially at local scale, remains limited. In this study, we conduct a thorough comparison of daily and sub-daily extreme precipitation from HCLIM3 and HCLIM12 across Norway, divided into eight regions, using gridded and in-suit observations. Our main focus is to investigate the added values of HCLIM3 compared to HCLIM12 for precipitation extreme indices at daily and sub-daily time-steps on both local and regional scales. We find that the HCLIM3 better captures the maximum 1-day precipitation (Rx1d) at most of the regions except south-western region. Notably, the performance of HCLIM3 in capturing Rx1d shows a notable coastal-inland division, overestimating along the coastal areas and underestimating in the inland regions. In general, HCLIM3 better matches observations than HCLIM12 for daily and sub-daily precipitation extreme indices at regional scale in Norway. However, at the local scale, neither HCLIM3 nor HCLIM12 can capture the temporal evolution of Rx1h during 10 years, except one station near Oslo (eastern region), where only HCLIM3 fits the observations. In general, HCLIM3 performs better than HCLIM12 on Rx1d and Rx1h in Norway with the mean of bias distribution closer to zero, although it varies a bit among regions (for example, HCLIM3 performs worse in the south-western region). In addition, the seasonality of Rx1h can be also better captured by HCLIM3 at both regional and local scales, while HCLIM12 tends to underestimate hourly extremes. In a future warming climate, HCLIM3 with higher Clausius-Clapeyron (CC) scaling, exhibits a higher increase than HCLIM12 in the Rx1h and Rx1d over most regions of Norway except southern and south-west regions. Under global warming, short-duration extreme events with greater CC scaling have a higher increase rate than long-lasting events. This study highlights the importance of more realistic convection-permitting regional climate predictions and projections in providing reliable insights into the characteristics of precipitation extremes and their future changes across Norway's eight regions. Such information is crucial for effective adaptation management to mitigate severe hydro-meteorological hazards, especially for the local extremes.

How to cite: Xie, K., Li, L., Sobolowski, S., Chen, H., and Xu, C.-Y.: Convection-Permitting Climate Models: Present and Future Insights on daily and sub-daily Extreme Precipitation in Norway, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16029, https://doi.org/10.5194/egusphere-egu24-16029, 2024.

12:20–12:30
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EGU24-12651
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CL3.1.1
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Highlight
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On-site presentation
Daniel Argüeso, Marta Marcos, and Ángel Amores

In September 2023, Storm Daniel hit the central Mediterranean and became the deadliest storm in the recorded history of the region. The storm originated from a low-pressure system around 4th September, which genesis can be attributed to an omega block centred in southern Europe. Then, it evolved into a Mediterranean tropical-like cyclone (medicane), impacting both the northern and the southern Mediterranean shores before dissipating around 12th September.

The storm particularly impacted Greece and Libya and, although the casualties and other major consequences are closely linked to significant infrastructure failures in Libya, both countries registered record-breaking rainfall amounts. For example, Zagora (Greece) experienced 754 mm in just 18 hours and Al-Bayda (Libya) saw a record highest daily rainfall of 414 mm. These events require an extraordinary supply of water vapor to maintain such rainfall rates. In the complex interplay of factors contributing to the development and intensity of weather systems like Storm Daniel, the Sea Surface Temperature (SST) stands as a likely primary driver. High SSTs provide not only the necessary energy, but also the moisture required to fuel the cyclone.

Over the months preceding Storm Daniel, the Mediterranean SST has consistently reached anomalously high levels, which was potentially a key ingredient in shaping the storm characteristics. To quantify the influence of local SST on the storm intensity, we used five ensembles of convection-permitting simulations (2 km) with an atmospheric model, which each of the ensemble members were initialized at different times. The five ensembles vary on the atmospheric and SST boundary and initial conditions, which were generated using different approaches to create counterfactual scenarios, from a simple removal of the mean climatological difference to an innovative data-driven method, which removes the long-term climate change signal correlated to global warming from SST. Combining these different estimates of atmosphere and SST counterfactual scenarios, we could quantify the relative contribution of global warming through local high SSTs and remote factors to rainfall amounts by Storm Daniel. In addition, we used a back-tracking algorithm to determine the source of water vapor that precipitated over Greece and Libya to understand the differences between the two phases of the event and the role of local SSTs. Our results show that local SST was crucial on the Libyan phase of the storm, while the rainfall amounts registered in Greece were mainly driven by remote factors. Also, the comparison of the different ensembles showed that the effects of long-term trends in SST are important in Libya, but the dominant contribution comes from the anomalous high SSTs that the region has recently experienced, which cannot be directly explained by mean climatological changes. In fact, these exception conditions are responsible for most of the record-breaking rainfall amounts observed during the second phase of the storm.

How to cite: Argüeso, D., Marcos, M., and Amores, Á.: The influence of high Mediterranean Sea surface temperature on Storm Daniel intense rainfall, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12651, https://doi.org/10.5194/egusphere-egu24-12651, 2024.

Lunch break
Chairpersons: Merja Tölle, Lorenzo Sangelantoni, Puxi Li
14:00–14:15
14:15–14:25
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EGU24-13661
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CL3.1.1
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ECS
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Highlight
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Virtual presentation
Shinto Roose, Laxmi Sushama, and Jeenu John

The impact of flood inundation on local weather pattens are investigated in this study, for the case of the flood event that impacted the Canadian regions of Ottawa, Gatineau, Montreal and surroundings during the spring of 2017 using high-resolution (4 km) regional climate model simulations, with and without flood inundation regions. In the absence of an interactive inundation parameterization in the regional climate model, flood inundated regions/grid cells are prescribed based on flood extent polygons derived from Radarsat-2 satellite imagery in the simulation that includes inundation. The flood event for most of the regions of interest was caused by rain-on-snow events, with the heavy rainfall in May being associated with a mid-latitude cyclone.

The control simulation, without inundation, driven by ERA5, accurately depicts the overall regional patterns of precipitation observed compared to Daymet, but exhibits large overestimation locally, i.e., in the vicinity of the flooded regions, during the 24 hours following the peak rainfall period. However, simulations with flood inundation reveal discernible variations in precipitation over the flood inundation regions, when compared to the control simulation, reducing the precipitation biases locally. This is brought by the temperature modulations and thereby temperature gradients in the simulation with inundation leading to circulation changes locally. Sensitivity experiments reveal robust results, i.e., improved precipitation with inundation representation, despite the small changes in precipitation associated with circulation changes for small changes in flood inundation fractions. The results suggest the need to incorporate dynamic flood inundation module in climate model simulations, especially at high resolutions, to improve the realism of simulations, which in addition to facilitating process understanding can also aid in adaptation planning of inundated regions.

How to cite: Roose, S., Sushama, L., and John, J.: Impact of Flood Inundation on Local Weather Patterns, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13661, https://doi.org/10.5194/egusphere-egu24-13661, 2024.

14:25–14:35
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EGU24-18175
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CL3.1.1
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ECS
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On-site presentation
Svenja Szemkus and Petra Friederichs

The detection of local climate change signals, in particular those related to extreme events, is challenging due to the large internal variability of the climate system. The BMBF-funded project ClimXtreme Module B-CoDEx focuses on improving the signal-to-noise ratio of climate change signals in extreme weather events using innovative data compression methods.

This study uses principal component analysis (PCA) for spatial extremes (Cooley and Thibaud, 2019) to analyse heatwaves and droughts over the northern hemisphere. An extremal pattern index (EPI) is introduced as an integrative measure of the intensity and spatial extent of an extreme heat anomaly. Its bivariate extension is used to account for simultaneous spatial extremes in two variables. EPI provides us with a compact description of heatwaves. We see, for example, that preceding precipitation deficits significantly influence the development of heatwaves, and that heat waves often coincide with instantaneous short-term droughts. 

To investigate extreme hourly precipitation, a scale-dependent decomposition using the dual-tree wavelet transform is proposed, as described e.g. in Buschow and Friederichs (2021). For this study, we rely on reanalysis data (COSMO-REA6, CERRA) over Germany. A comparison of the two datasets regarding their representation of large- and small-scale events shows significant differences, especially for the small-scale events. Furthermore, we apply established methods to perform a scale-dependent detection of extreme precipitation and to reveal trends that are hidden by variability on other scales. 

How to cite: Szemkus, S. and Friederichs, P.: Investigating heatwaves/droughts and convective precipitation extremes using compact descriptions of spatio-temporal fields, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18175, https://doi.org/10.5194/egusphere-egu24-18175, 2024.

14:35–14:45
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EGU24-10350
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CL3.1.1
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On-site presentation
Luiza Vargas-Heinz, Erika Coppola, and Matilde García-Valdecasas Ojeda

In the last 10 years, the very high resolution regional climate models have started to be used and recently the newly available regional climate model ensemble for the Great Alpine region, at the convection permitting (CP-RCM) resolution (> 3 km), has been released by the CORDEX Flagship Pilot Study on Convective phenomena at high resolution over Europe and the Mediterranean (FPSCONV). At such resolution, the improvement of the representation of local hydrological processes becomes relevant because the climate impact on the hydrological cycle at that scale is expected to be much better captured.  

To this aim, the CETEMPS hydrological model (CHyM) is used coupled off-line with the different CP-RCM ensemble members.  The model has been run in two different configurations, using either temperature and precipitation from the driving CP-RCM or directly the runoff. The hydrological simulation ensemble has been validated against local station data for the Po river and central Italian river basins, by using hydrological indicators, such as the Kling–Gupta efficiency (KGE). The climate change projections are compared with previous lower resolution simulation driven by convection parametrized regional climate models from the Euro-CORDEX ensemble.  

How to cite: Vargas-Heinz, L., Coppola, E., and García-Valdecasas Ojeda, M.: Impact of climate change on the hydrological cycle of the Great Alpine region by means of regional climate convection permitting high resolution simulations and hydrological model simulations. , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10350, https://doi.org/10.5194/egusphere-egu24-10350, 2024.

14:45–14:55
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EGU24-4916
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CL3.1.1
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On-site presentation
Kalle Nordling, Bjørn Samset, and Nora Fahrenbach

Climate change can involve changes in mean conditions, and in their variability on short to long timescales. But which of the two  is more important for our future climate?  We present a study indicating that for the number of extreme precipitation days, changes in climate variability dominate over  changes in the mean state. This analysis is based on three large ensemble simulations across three CMIP6 models (MPI-ESM1-2-LR, CanESM5, and ACCESS-ESM1-5). Here, we decompose the total changes in daily summer precipitation and daily maximum temperature into mean and variability components (standard deviation and skewness of the daily probability density functions).  Our key findings are that:1) Changes in climate variability (i.e., day-to-day variability of precipitation and changes in the precipitation distribution) have a more pronounced impact on extreme precipitation events than changes in the mean state. 2) In contrast, changes in the mean temperature state play a more dominant role in determining overall changes in daily temperature. These insights  are valuable for understanding the mechanisms driving extreme weather events and  highlight the need to consider daily variability changes in climate change impact assessments.

How to cite: Nordling, K., Samset, B., and Fahrenbach, N.: Climate variability outweighs influence of climate mean on summer precipitation extremes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4916, https://doi.org/10.5194/egusphere-egu24-4916, 2024.

14:55–15:05
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EGU24-733
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CL3.1.1
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ECS
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On-site presentation
Mehmet Baris Kelebek, Fulden Batibeniz, and Barış Önol

The frequency and severity of extreme weather events, including temperature and precipitation extremes, have been increasing globally due to human-induced climate change. The Black Sea Basin (BSB), with its complex topography and strong air-sea interactions, is particularly susceptible to climate change and serves as a hot-spot for studying regional climate extremes. To obtain reliable information in BSB, high-resolution convection-permitting simulations are necessary. In this research, we performed convection-permitting climate simulations for historical (2005–2014) and future (2061–2070) periods to investigate the changes in temperature and precipitation extremes and underlying mechanisms based on the SSP3-7.0 climate change scenario over the BSB. To achieve this, we downscaled the CMIP6-based MPI-ESM1.2-HR outputs to 3 km horizontal resolution using the WRF model. The future simulation demonstrates an increased exposure to warm extremes as indicated by the positive change of the TX90P index by about 18% and an increase of the heat wave duration index (HWDI) reaching 55 days per year over the BSB. These changes primarily occur over the highlands of Eastern Anatolia due to enhanced land-atmosphere interactions. In March, a change in low-level circulation leads to a sudden warming of approximately 6°C and an early onset of the melting season, resulting in a 20% reduction in snow cover over Eastern Anatolia. This shift increases extreme temperatures due to a substantial snow albedo feedback caused by a 10% reduction in surface albedo in this area. Furthermore, our analyzes highlight the intensification of daily and sub-daily precipitation along the coastal regions of the Black Sea. Particularly in winter and autumn, the ratio of daily extreme precipitation amounts to the seasonal total precipitation (R90PTOT index) reaches 45% in the future over the eastern Black Sea. Additionally, daily precipitation probabilities shift towards higher values for extreme precipitation amounts in the same area with maximum precipitations exceeding 280 mm/day. At the sub-daily scale, this region experiences an intensification in hourly precipitation throughout the day due to a 22% increase in low-level moisture flux resulting from 1°C warmer sea surface temperatures in winter. The increased extreme precipitation in the autumn is associated with the intensification of afternoon precipitation along the Black Sea coasts of Türkiye. This study emphasizes the importance of convection-permitting climate simulations in improving our understanding of climate extremes in the topographically complex BSB. It provides valuable insights for mitigation and adaptation efforts in this climate change hot-spot.

Acknowledgment: The numerical calculations reported in this paper were fully performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRUBA resources).

How to cite: Kelebek, M. B., Batibeniz, F., and Önol, B.: Highlighting future climate extremes in CMIP6-based convection-permitting simulations over the Black Sea Basin, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-733, https://doi.org/10.5194/egusphere-egu24-733, 2024.

15:05–15:15
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EGU24-4436
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CL3.1.1
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ECS
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On-site presentation
Miraj Kayastha, Pengfei Xue, Chenfu Huang, Jiali Wang, Zhao Yang, William Pringle, Tirthankar Chakraborty, Yun Qian, and Robert Hetland

When cold, dry air travels over a relatively warmer lake, lake-effect snow (LES) develops due to an increase in moisture flux from the lake to the atmosphere, which in turn promotes cloud formation and subsequent precipitation. A destructive LES storm struck the Buffalo region in New York, from November 17-20, 2022. Buffalo, located at the eastern end of Lake Erie and subject to winter winds that sweep across the lake, was inundated with nearly 7 feet of snow, prompting the declaration of federal emergencies by multiple counties. The LES storm highlighted the need for at-risk communities to enhance their preparedness for comparable future incidents. Using a cloud-resolving 4 km scale, we investigated how such an LES storm might manifest in a warmer future climate by employing the Pseudo-Global Warming (PGW) method and a two-way coupled lake-atmosphere regional climate modeling system. The modeling system comprises a two-way coupled Weather Research and Forecasting (WRF) model and a Finite Volume Community Ocean Model (FVCOM)-based three-dimensional lake model. Under the PGW methodology, the future atmospheric forcing necessary for our regional climate modeling system was derived from a reanalysis climate dataset by incorporating projected atmospheric changes from a variety of CMIP6 earth system models. Furthermore, we integrated the warming signals in the lakes by utilizing the projected lake conditions obtained from a regional climate modeling system that was previously established and also incorporated an FVCOM-based lake model. According to our findings, the total storm precipitation for such an event by the end of this century could increase by 14% under a high-emission scenario, with an increase in rainfall at the expense of snowfall. Under the present-day climate conditions, snowfall was the primary type of precipitation experienced during the event. However, in a warmer future climate, the distribution of precipitation might be nearly equal between snowfall and rainfall. By conducting two additional simulations in which either the lake or atmosphere is warmed individually using the projected future conditions, we found that the warmer lakes primarily contributed to the increase in storm precipitation through increased evaporation, while the warmer atmosphere primarily influenced the form of storm precipitation during such an LES storm in the future.

How to cite: Kayastha, M., Xue, P., Huang, C., Wang, J., Yang, Z., Pringle, W., Chakraborty, T., Qian, Y., and Hetland, R.: How Could Lake-Effect Snow Storms Evolve in a Warming Future Climate?, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4436, https://doi.org/10.5194/egusphere-egu24-4436, 2024.

15:15–15:25
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EGU24-20433
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CL3.1.1
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On-site presentation
Nauman K. Awan, Christoph Wittmann, Clemens Wastl, and Florian Meier

In recent decades reanalysis products have emerged as a pivotal resource for numerical model evaluations, significantly enhancing our understanding of Earth’s system. They have also been employed in various projects aimed at climate monitoring and assessment of climate change impacts. In this study, we present first results from ongoing work aimed at creating a first of its kind high resolution reanalysis ensemble for Austria. ECMWF's ERA5 ensemble is downscale to a 2.5 km resolution by employing three-dimensional variational assimilation (3DVAR) system available in AROME. Upon completion, this dataset will provide spatially, temporally, and physically consistent 3D and 2D atmospheric fields spanning from 2012 to 2022. The presented analysis focused on representation of three distinct extreme precipitation events simulated in a one and a half year long simulation (01-01-2021 to 30-06-2022). The reanalysis ensemble is compared with operational weather models and a high resolution (1 km x 1 km) gridded observational reanalysis. Based on statistical scores, all variations are ranked. In general, the results are on par with our operational models, however, some ensemble members exhibit slightly better performance compared to our operational models, which highlights the advantages of employing an ensemble system.

How to cite: Awan, N. K., Wittmann, C., Wastl, C., and Meier, F.: High resolution regional re-analysis ensemble for Austria, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20433, https://doi.org/10.5194/egusphere-egu24-20433, 2024.

15:25–15:35
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EGU24-11440
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CL3.1.1
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ECS
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Highlight
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On-site presentation
Amarys Casnin, Gilles Bellon, Marania Hopuare-Klouman, Cécile Caillaud, Victoire Laurent, and Sophie Martinoni-Lapierre

Islands of French Polynesia, located in the tropical Pacific Ocean, are small – Tahiti, the largest is about 50 km long – and can exhibit complex orography due to their volcanic origin. In order to simulate properly the atmospheric flow and convective motions over these islands, the non-hydrostatic model AROME is used at high-resolution (2.5 km) to produce a 20-year simulation of the climate over the Society Islands as well as part of the Tuamotu archipelago and Austral Islands. This simulation enables to evaluate AROME ability to simulate these island climates, particularly in terms of rainfall and wind.

AROME is significantly better than the quasi-hydrostatic regional climate model ALADIN with coarser resolution (20 km) at simulating the climate of French Polynesia, and provides a better description of this climate than the available gridded observation products.

By comparing model’s precipitation to observed precipitation at weather stations, results generally show a correct simulation of mean daily rainfall and diurnal cycles. There is however a dry bias for windward stations over Tahiti and a wet bias for leeward stations. These biases remain relatively weak and less pronounced than the biases of other gridded datasets such as IMERG and CMORPH satellite estimates.

The model also simulates winds that compare well to in situ observations and other gridded data. The typical island effect on low-level circulation is well simulated by AROME contrary to ERA5 and satellite data.

How to cite: Casnin, A., Bellon, G., Hopuare-Klouman, M., Caillaud, C., Laurent, V., and Martinoni-Lapierre, S.: High-resolution simulation of French Polynesia climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11440, https://doi.org/10.5194/egusphere-egu24-11440, 2024.

15:35–15:45
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EGU24-18290
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CL3.1.1
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ECS
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On-site presentation
Berkin Gümüş, Sertaç Oruç, İsmail Yücel, and Mustafa Tuğrul Yılmaz

This study employs the latest versions of global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to evaluate climate extremes in Türkiye from 2015 to 2100 under two future scenarios, SSP2-4.5 and SSP5-8.5. Utilizing a number of high resolution CMIP6 models and different scenarios over the full projection period make this study unique over the region. To downscale coarse-resolution climate models to approximately 9 km (0.1° × 0.1°) spatial resolution, Quantile Delta Mapping (QDM) is employed. The downscaling process utilizes the European Centre for Medium-Range Weather Forecasts Reanalysis 5-Land (ERA5-Land) dataset as the reference data. Analysis of 12 extreme precipitation indices (EPIs) and 12 extreme temperature indices (ETIs) between 2015 and 2100 consistently indicates an increased frequency and intensity of extreme weather events in Türkiye under both future scenarios. The SSP5-8.5 scenario predicts a higher degree of water stress compared to SSP2-4.5, with a 20% reduction in total precipitation in the Aegean and Mediterranean regions of Türkiye. Despite an overall decrease in precipitation, the findings suggest an increase in the severity and frequency of extreme precipitation events. This implies that a greater proportion of total precipitation will be contributed by these extreme events. Anticipated trends include an increase in temperature extremes, encompassing both the lowest and highest daily maximum temperatures across all regions of Türkiye. This signifies a warming signal of up to 7.5 °C by the end of the current century. Cold extremes also exhibit a tendency towards warming, as evidenced by a significant decrease in the number of ice days across all areas. This trend may potentially result in less snow accumulation, which negatively affects various sectors.

How to cite: Gümüş, B., Oruç, S., Yücel, İ., and Yılmaz, M. T.: Assessing Future Climate Extremes in Türkiye: A High Resolution CMIP6-based Analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18290, https://doi.org/10.5194/egusphere-egu24-18290, 2024.

Posters on site: Wed, 17 Apr, 10:45–12:30 | Hall X5

The posters scheduled for on-site presentation are only visible in the poster hall in Vienna. If authors uploaded their presentation files, these files are linked from the abstracts below, but only on the day of the poster session.
Display time: Wed, 17 Apr 08:30–Wed, 17 Apr 12:30
Chairpersons: Lorenzo Sangelantoni, Douglas Maraun, Emanuela Pichelli
X5.159
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EGU24-2517
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CL3.1.1
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ECS
Tianmeng Chen

This study examines an extreme wind gust event of over 45 m s-1 occurring in the Yangtze River Delta (YRD) in East China on 30 April 2021, which broke the historical record of surface wind speeds of 221 automated weather stations. A high-resolution mesonet of eight radar wind profilers (RWPs) and six triangular regions along the path of the propagating wind gust is utilized to investigate the dynamics of the extreme wind gust event. Downward transport of turbulence and momentum, and the changes in vertical divergence and vorticity distributions during the event are analyzed. Downward momentum transport likely contributes to the formation of a gust front, and the combination of a gust front and a mesocyclone is of significance in the formation of the extreme wind gust in addition to the large-scale environment. Intensification in mesoscale circulation produced by the merging process likely results in new convection initiation, which potentially accelerates the surface wind through intensified wind shear, and ultimately resulting in the occurrence of the extreme wind gust. This study highlights the role of multiscale processes in the formation of extreme wind gust, as well as the advantage of the non-negligible capability of RWP mesonet in monitoring the turbulence and momentum transport during the passage of the extreme wind systems. The RWP mesonet can serve as a good entry point in extreme wind nowcasting and prediction studies in the future.

How to cite: Chen, T.: An Observational Analysis of the Evolution and Structures of an Extreme Wind Gust Event in East China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2517, https://doi.org/10.5194/egusphere-egu24-2517, 2024.

X5.160
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EGU24-2976
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CL3.1.1
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ECS
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Puxi Li, Fengfei Song, Haoming Chen, Jian Li, Andreas Prein, and Wenxia Zhang

 As one of the major producers of extreme precipitation, mesoscale convective systems (MCSs) have received much attention. Recently, MCSs over several hotpots, including the Sahel and US Great Plains, have been found to intensify under global warming. However, relevant studies on the East Asian rainband, another MCS hotpot, are scarce. Here, by using a novel rain-cell tracking algorithm on a high spatiotemporal resolution satellite precipitation product, we show that both the frequency and intensity of MCSs over the East Asian rainband have increased by 21.8% and 9.8% respectively over the past two decades (2000-2021). The more frequent and intense MCSs contribute nearly three quarters to the total precipitation increase. The changes in MCSs are caused by more frequent favorable large-scale water vapor-rich environments that are likely to increase under global warming. The increased frequency and intensity of MCSs have profound impacts on the hydroclimate of East Asia, including producing extreme events such as severe flooding. 

How to cite: Li, P., Song, F., Chen, H., Li, J., Prein, A., and Zhang, W.: Intensification of mesoscale convective systems in the East Asian rainband over the past two decades, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2976, https://doi.org/10.5194/egusphere-egu24-2976, 2024.

X5.161
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EGU24-3043
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CL3.1.1
Zbyněk Sokol and Jana Popova

This contribution focuses on the change in 1h heavy precipitation distribution in response to the increasing air temperature in Czechia (Central Europe). The air temperature, the dew point temperature and the temperature of lifting condensation level are used as temperature characteristics. The change in the distribution of 1h precipitation measurements is compared with the results of reanalyses based on simulations of ALADIN-CZ NWP model and with the results of future climate simulations by ALADIN-CLIMAT-CZ climate model. In general, the increase in heavy precipitation appears clearly in the very upper part of precipitation distribution. Values of the upper percentiles of precipitation increase up to a certain temperature threshold and then they decrease, which is in line with other studies. This is also visible in the simulations of future climate.

How to cite: Sokol, Z. and Popova, J.: Change in the distribution of heavy 1h precipitation due to temperature changes in measured values, model reanalyses and model simulations of future climate, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3043, https://doi.org/10.5194/egusphere-egu24-3043, 2024.

X5.162
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EGU24-3707
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CL3.1.1
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ECS
Yang Zhang, Liping Liu, and Hao Wen

For quantitative precipitation estimation (QPE) based on polarimetric radar (PR) and rain gauges (RGs), the quality of the radar data is crucial for estimation accuracy. A combined radar quality index (CRQI) is proposed to represent the quality of the radar data used for QPE and an algorithm that uses CRQI to improve the QPE performance. Nine heavy rainfall events that occurred in Guangdong Province, China, were used to evaluate the QPE performance in five contrast tests. The QPE performance was evaluated in terms of the overall statistics, spatial distribution, near real-time statistics, and microphysics. CRQI was used to identify good-quality data pairs (i.e., PR-based QPE and RG observation) for correcting estimators (i.e., relationships between the rainfall rate and the PR parameters) in real-time. The PR-based QPE performance was improved because estimators were corrected according to variations in the drop size distribution, especially for data corresponding to 1.1 mm < average Dm < 1.4 mm, and 4 < average log10 Nw < 4.5. Some underestimations caused by the beam broadening effect, excessive beam height, and partial beam blockages, which could not be mitigated by traditional algorithms, were significantly mitigated by the proposed algorithm using CRQI. The proposed algorithm reduced the root mean square error by 17.5% for all heavy rainfall events, which included three precipitation types: convective precipitation (very heavy rainfall), squall line (huge raindrops), and stratocumulus precipitation (small but dense raindrops). Although the best QPE performance was observed for stratocumulus precipitation, the biggest improvement in performance with the proposed algorithm was observed for the squall line.

How to cite: Zhang, Y., Liu, L., and Wen, H.: Combined Radar Quality Index for Quantitative Precipitation Estimation of Heavy Rainfall Events, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3707, https://doi.org/10.5194/egusphere-egu24-3707, 2024.

X5.163
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EGU24-3771
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CL3.1.1
Pavel Faško, Oliver Bochníček, and Ladislav Markovič

Summer and tropical days were and are part of the processing of historical observations. Their processing was the content of each monthly report of meteorological observations as well as the annual processing in the form of a yearbook. Changes in temperature (especially positive deviations from normal values) also cause their more frequent occurrence. This would not be unusual or unexpected, even if the regularity of these periods cannot be predicted. Higher air temperatures often cause health problems, especially for older and more sensitive people. Nausea and loss of concentration occur especially during longer periods of hot days. In this contribution, we decided to process the occurrence of periods of summer days (t_max≥25 °C) and periods of tropical days (t_max≥30 °C). The term period here means consecutive days (minimum 2). Professional and aerial meteorological stations covering the territory of Slovakia well were selected. Their length was considered for two normal periods, namely 1961-1990 and 1991 - 2020. The mutual comparison gave us a clear idea of the redistribution of periods of different lengths and the territorial unit (places in Slovakia). While for summer days we observe a decrease in shorter periods and an increase in longer periods, especially in lowland areas, in the rest of the territory, especially in the north, or in mountainous areas, rather an increase even from the shortest periods.

On tropical days, or when comparing the periods of tropical days in both normal periods (1961 - 1990 and 1991 - 2020), we find the fact of a very strong increase from the shortest periods of consecutive tropical days at all selected meteorological stations. Since it is impossible to compare the frequency of periods as well as the number of tropical days themselves in absolute terms, we helped ourselves with a percentage evaluation. The fact is that, especially for tropical days, the biggest increase is in the north of the country, the shortest periods (2-3 days in a row) increased by up to 250%. They even began to appear in places where they could not be observed in the period 1961 - 1990. The results conceived in this way will help not only the tourism industry, but also the adaptation of man and his environment to changes in the climate system.

 

How to cite: Faško, P., Bochníček, O., and Markovič, L.: Summer and tropical consecutive days in normal periods 1961-1990 and 1991-2020., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3771, https://doi.org/10.5194/egusphere-egu24-3771, 2024.

X5.164
|
EGU24-4924
|
CL3.1.1
Pai Hsin-Wen and Lin Yuan-Chien

The Analysis of Different Spatial-temporal Rainfall Characteristics and Drought Disaster Risk Assessment in Penghu Area

 

Keywords: Empirical Orthogonal Function, Wavelet Analysis, Standardized Precipitation Index, Drought

 

Under the impact of extreme climate and the trend of global warming, the frequency of natural disasters has increased, and extreme rainfall and extreme drought events have gradually increased, causing threats to human life, food shortages, and ecological catastrophes. In recent years, with the development of tourism industry in Penghu, the demand for water resources has increased, but available surface water sources are very scarce. At present, Penghu’s freshwater source is mainly seawater desalination, but this method is likely to affect Penghu’s unique coral reef marine ecology.

This study uses data mining methods to analyze rainfall characteristics and drought trends. Rainfall characteristic analysis uses empirical orthogonal function (EOF) and wavelet analysis (WA), and drought trend analysis uses the Standardized Precipitation Index (SPI) at different time scales. The results show that the rainfall characteristics of South Penghu Marine National Park and Penghu Island are different, and the rainfall difference between drought years and non-drought years is large. The drought index shows that in recent years, South Penghu Marine National Park is still in a relatively dry state, with a higher drought frequency than Penghu Island and Taiwan Island. The risk of agricultural drought and hydrological drought is high on a medium to long time scale. Therefore, special attention needs to be paid to the rainfall situation in South Penghu Marine National Park.

How to cite: Hsin-Wen, P. and Yuan-Chien, L.: The Analysis of Different Spatial-temporal Rainfall Characteristics and Drought Disaster Risk Assessment in Penghu Area, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4924, https://doi.org/10.5194/egusphere-egu24-4924, 2024.

X5.165
|
EGU24-6617
|
CL3.1.1
|
ECS
Beatrice Lioi, Krzysztof Kochanek, Tiziana Bisantino, and Vito Iacobellis

An increasing perception of climate change both on a global and local scale, accompanied by the increase in observed average surface temperature of the oceans, and by the increased frequency of extreme events in different territories, creates the necessity of developing hydrological tools and models within the framework of non-stationarity. This study analyses the daily and hourly rainfalls recorded in Puglia (Southern Italy). In scientific literature the widely used non-parametric Mann-Kendall (MK) test is suggested to identify monotonic trends, then followed by the application of a further non-parametric measure of trend, the Sen's Slope. Indeed, in parametric methods the non-stationary character is exercised with the addition of the temporal variable (co-variant) t in the probability distribution. In this framework the Two-Stage (TS) method allows to tackle this problem by associating the linear or non-linear temporal dependence to both mean and standard deviation of time series (Kochanek et al., 2013). In this field, we propose an advancement of the TS methodology by introducing a polynomial function in the mean trend, leaving the variance trend linear. The obtained results represent the first non-linear application of the TS method in a non-stationary approach to extreme events. With such application of the TS method, we show how to update the evaluation of quantiles with 5 or 10 years return time, in the aim of a technical application to hydraulic risk management and urban planning.

How to cite: Lioi, B., Kochanek, K., Bisantino, T., and Iacobellis, V.: Two-stage non-linear approach in the analysis of precipitation time series , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6617, https://doi.org/10.5194/egusphere-egu24-6617, 2024.

X5.166
|
EGU24-6926
|
CL3.1.1
|
ECS
Attribution of tropical sea surface temperature change on extreme precipitation over the Yangtze River Valley in 2020
(withdrawn)
Qian Wang, Panmao Zhai, and Baiquan Zhou
X5.167
|
EGU24-7573
|
CL3.1.1
Xia Li

This study mainly presents the spatiotemporal characteristics and changes of near-surface wind speed with observations from 679 stations over China for 1979–2019. Furthermore, mechanisms of the wind speed changes are also investigated. Major results show that the larger near-surface wind speed mainly occur in northern and eastern regions, Tibetan Plateau and the coastal zones in China. The wind speed in spring is larger than the other seasons with mean value of 2.57 m s−1. Significantly, decreased near-surface wind speed trend in China is detected during 1979–2019, particularly in 1979–1996. The mean rates of decrease in 1979–2019 and 1979–1996 are−0.06 m s−1 (10a)−1 and−0.19 m s−1 (10a)−1, respectively. The decreased trends of the high wind speed percentiles are more significant than the low, especially in 1979–1996. The change rate of the 95th wind speed percentile in 1979–1996 even reaches to −0.48 m s−1 (10a)−1 and passes the significance test at p<0.05. However, the wind speed trend reversed after 1997. The lowest 5th wind speed percentile has the most significant reversal trend. Therefore, the decreased wind speed trend before 1997 is mainly caused by the significant reduction of strong wind, while the reversal trend after 1997 results from weak wind. The variations of the wind speed over China attributed to both the U and V wind components. The significantly declined trend of the surface wind speed is closely related to the weakened upper westerly wind field. In addition, the uneven warming between high and low latitudes may also contribute to the surface wind speed changes through thermal adaption.

How to cite: Li, X.: The study of the spatiotemporal variations and mechanisms for the near‑surface wind speed in China during 1979-2019, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7573, https://doi.org/10.5194/egusphere-egu24-7573, 2024.

X5.168
|
EGU24-8043
|
CL3.1.1
|
ECS
|
Highlight
Florian Ruff and Stephan Pfahl

Extreme precipitation events can cause flooding in central European river catchments. Climate simulations show that extreme precipitation, especially towards longer return periods, will intensify in a warmer climate for most parts of Europe. In order to study the mechanisms leading to the intensification of particularly extreme events, we investigate 10-year daily precipitation events over five major central European river catchments in Community Earth System Model Large Ensemble simulations. A statistical evaluation and comparison of large-scale circulation patterns associated with the events with operational ensemble weather prediction data from the ECMWF indicate a realistic representation of the 10-year extreme events in the climate model. Differences in these circulation patterns are analysed between the historical climate of 1990-2000 and a warmer climate at the end of the century (2091-2100). While most events occur in the core summer months (June-August) in the historical climate, there is a broadening of the seasonal distribution with extreme events from May to October in the warmer climate. Precipitation rates increase locally by 5-7%/K, similar to the Clausius-Clapeyron rate, related to significant increases in lower-tropospheric humidity. Averaged over the entire catchments, precipitation still increases, but with lower intensification rates varying between 1.2 and 3.8%/K for the individual catchments. This is due to a combination of thermodynamic and dynamic factors, in particular the shift towards the cold season, associated with smaller temperature increases during the events than expected from the overall warming, and a weakening of vertical motion over parts of the catchments. In future research, the robustness of these findings should be investigated through comparison with other climate simulations.

How to cite: Ruff, F. and Pfahl, S.: Projected future changes of very extreme precipitation events over central European river catchments from ensemble climate simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8043, https://doi.org/10.5194/egusphere-egu24-8043, 2024.

X5.169
|
EGU24-9342
|
CL3.1.1
Francesca Raffaele, Erika Coppola, Leidinice Silva, Maria Laura Bettolli, Josefina Blasquez, Jesus Fernandez, Josipa Milovac, Rosmeri Porfirio da Rocha, and Silvina Solman

A set of high resolution simulations have been performed over the La Plata region in South America, and a multi-model ensemble of Convection-Permitting simulations has been produced for a 3-years period (2018-2021). We have used this new high resolution ensemble to investigate more in depth the daily and hourly timescales.

The available satellite and gridded observational datasets show a clear uncertainty  when going to sub-daily timescale, therefore the validation of the model ensemble mean and extreme precipitation is performed by including also a station based observational dataset at both daily and hourly time scale, to assess  the model uncertainty within the context of the aforementioned observational uncertainty.

Moreover, a cluster analysis of the diurnal cycle precipitation has been used as a starting point for a spatial characterization of the precipitation in a region of heterogeneous topography. The ensemble models' performance has been validated inside five different regions in order to spatially homogenize the precipitation regimes at hourly timescales.

The results underlined a good agreement in the model ensemble especially in those areas where the homogenization of the stations is more pronounced.

On the other hand, the spread among models grow when looking at areas characterized by complex orography, thus highlighting the importance of having available a set of simulations as big as possible so that complexity can be represented within the  model uncertainty. 

How to cite: Raffaele, F., Coppola, E., Silva, L., Bettolli, M. L., Blasquez, J., Fernandez, J., Milovac, J., Porfirio da Rocha, R., and Solman, S.: Convection-Permitting simulations over South America: a look at the uncertainty sources at the sub-daily time scale, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9342, https://doi.org/10.5194/egusphere-egu24-9342, 2024.

X5.170
|
EGU24-12321
|
CL3.1.1
|
ECS
|
Highlight
Martina Messmer, Santos J. González Rojí, Christoph C. Raible, and Thomas F. Stocker

The climate in Africa is very diverse ranging from tropical rainforest to deserts. Also, East Africa is covered by different climate zones and is very dry compared to other tropical regions. This is owed to various large-scale drivers, such as the complex topography, large water bodies such as Lake Victoria and vicinity to the Indian Ocean. The southern part of East Africa is characterized by two rainy seasons, which are separated by dry periods. The long rains from March to May feature more continuous precipitation, while the short rains from October to November show high interannual variability with days of high precipitation intensities and drier intervals.

The CMIP5 and CMIP6 models project a general wetting of East Africa in the future, with a high model agreement. To obtain a better understanding of what this means for extreme precipitation and changes in the hydrological cycle we performed three different regional downscaling simulations using WRF: one for the present period from 1981–2010, and two for the end of the century (2071–2100). The latter two simulations are driven by, the RCP2.6 and the RCP8.5 scenarios, and the respective global forcing fields are based on CESM model runs. The regional model covers four different domains, whereby the first extends from the Sahara down to Madagascar with 27 km horizontal resolution, the second domain focuses on East Africa with 9 km resolution, the third domain at 3 km resolution zooms into the western part of Kenya, covering land with complex topography, and the last domain centers on Mount Kenya and surroundings at 1 km resolution.

Preliminary results show that the rainy seasons are difficult to capture by WRF, when driven by a global climate model. This might be related to the fact that some of the atmospheric circulation is misrepresented in the global model and cannot be corrected by the regional model dynamics. While the long rains are underestimated in the present compared to a downscaling of ERA5, the short rains show an overestimation. A sensitivity study with adjusted SSTs to overcome some of the circulation issues in the global climate model only weakly improves the results. The projections for the future show an increase in extreme precipitation days, but also in the extreme daily precipitation amounts compared to present extreme (p99) precipitation. While the rainy seasons are projected to be more intense, the dry seasons tend to become drier, leaving some months without precipitation at all. The results further suggest that the extreme precipitation events do not differ for the RCP2.6 and RCP8.5. Thus, extreme precipitation events in Kenya might be limited by an upper bound, but this is subject of ongoing research.

How to cite: Messmer, M., González Rojí, S. J., Raible, C. C., and Stocker, T. F.: Changes in extreme precipitation in East Africa and Mount Kenya based on high-resolution regional climate model simulations for the end of the 21st century, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12321, https://doi.org/10.5194/egusphere-egu24-12321, 2024.

X5.171
|
EGU24-12413
|
CL3.1.1
Matilde García-Valdecasas Ojeda, David Donaire-Montaño, Feliciano Solano-Farias, Juan José Rosa-Cánovas, Emilio Romero-Jiménez, Nicolás Tacoronte, Yolanda Castro-Díez, María Jesús Esteban-Parra, and Sonia R. Gamiz-Fortis

High mountain regions are characterized by a high spatiotemporal variability in their climatic variables. Unfortunately, in these regions there is a lack of climatic information, mainly due to its difficult accessibility, and if any, it is usually short, sparse, or incomplete with numerous gaps and outliers. Sierra Nevada (SN), located in the southern Iberian Peninsula (IP), constitutes a double hot spot as it is a mountain region located in the Mediterranean, both of which are particularly vulnerable to climate change.

To investigate the impact of climate change on mountainous ecosystems in SN, a high-resolution dataset for this region, HighResClimNevada, was created for the period from 2001 to 2020. For this purpose, the Weather Research and Forecasting (WRF) model version 4.3.3 driven by ERA5 reanalysis was used as convection permitting model (CPM) with a two “one-way” configuration to achieve simulated climatic fields over SN with 1 km spatial resolution. Because SN is topographically complex, the parent domain (d01) was configured spanned the entire IP with 5 km spatial resolution, while the nested domain (d02) was centered in SN but covered the entire Andalusia region. Maximum and minimum temperatures, precipitation, wind speed, solar incoming radiation, relative humidity, and surface pressure available are available in HighResClimNevada.

HighResClimNevada has been evaluated in terms of precipitation and maximum and minimum temperatures using bioclimatic and extreme indices, which are of special interest for ecologists and botanists. For this evaluation, we compared climatic fields from HighResClimNevada to observational gridded products from different sources (i.e., station-based products, satellite, and reanalysis), but also with in-situ weather stations located in the study region. In general, results indicate that HighResClimNevada has a good ability to represent the general climate characteristics in SN, making it a very useful tool for studying climate, its impact, and trends in this complex region.

Data availability: HighResClimNevada is available on the World Data Center for Climate (WDCC) at DKRZ (https://doi.org/10.26050/WDCC/HighresolClimNevada_eval).

Acknowledgements: This research has been carried out in the framework of the projects PID2021-126401OB-I00, funded by MCIN/AEI/10.13039/501100011033/FEDER Una manera de hacer Europa, LifeWatch-2019-10-UGR-01 co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014–2020 (POPE) LifeWatch-ERIC action line, and the project P20_00035 funded by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades.

How to cite: García-Valdecasas Ojeda, M., Donaire-Montaño, D., Solano-Farias, F., Rosa-Cánovas, J. J., Romero-Jiménez, E., Tacoronte, N., Castro-Díez, Y., Esteban-Parra, M. J., and Gamiz-Fortis, S. R.: A very High-resolution Climate Dataset for a High-altitude Region in Southern Spain: Sierra Nevada (HighResClimNevada), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12413, https://doi.org/10.5194/egusphere-egu24-12413, 2024.

X5.172
|
EGU24-12958
|
CL3.1.1
|
ECS
|
Freddy Pinochet, Hugo Beltrami, Elena Garcia-Bustamante, Jorge Navarro, and Fidel Gonzalez-Rouco

We use the Weather Research and Forecasting (WRF4.4) model for a regional climate simulation in Atlantic Canada. We seek to establish a robust repository of future climate projections for the region, that include the influence of northern ice coverage from the Labrador Sea and Ungava Bay, and sea surface temperatures (SST). The simulation is bounded by a Bias-Corrected ensemble of 18 CMIP6 General Circulation Models (GCMs) that offer better quality boundary conditions than the individual CMIP6 models in terms of the climatological mean, interannual variance and extreme events.

The simulation extends within the historical period from 1980 to 2014 and two future scenarios (SSP245 and SSP585) from 2015 to 2100. The configuration includes three domains with progressively increasing resolution from 30km to 9km and 3km. The finest resolution of 3 km by 3 km covers an area of approximately 561 kilometers by 462 kilometers around the province of Nova Scotia, Canada. The temporal resolution in WRF is set at 180 seconds, with boundary conditions updated every 6 hours, yielding output at a 6-hour time step for all WRF variables.

To validate the historical simulation, we use the reanalysis from ECMWF (ERA5)  and Station-Level Inputs and Cross-Validation for North America from The Oak Ridge National Laboratory (DAYMET). Preliminary statistical metrics reveal that our historical simulation underestimates the daily maximum temperature by 13%, overestimates daily minimum temperature by 2.7%, and underestimates the daily total precipitation by 16%. These findings provide valuable insights into the model performance and variability, and highlight areas for potential refinement for our projection scenarios. Analyses of the future (2015-2100) simulations are focused on estimating future precipitation (convective permitting), and surface air temperature (T2) extreme events.

How to cite: Pinochet, F., Beltrami, H., Garcia-Bustamante, E., Navarro, J., and Gonzalez-Rouco, F.: Regional Climate Projection for Atlantic Canada under SSP245 and SSP585, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12958, https://doi.org/10.5194/egusphere-egu24-12958, 2024.

X5.173
|
EGU24-13750
|
CL3.1.1
|
ECS
|
Highlight
Climate Risk Assessment Framework for Tornadoes
(withdrawn)
Mahkameh Zarekarizi, Amina Ly, Bharathan Balaji, Esther Branch, and Kommy Weldemariam
X5.174
|
EGU24-14514
|
CL3.1.1
|
ECS
Rajeswari Jayarajan Roshini, Christos Fountoukis, Azhar Siddique, Shamjad Moosakutty, Mohammedrami Alfarra, and Mohammed Ali Ayoub

Qatar has witnessed substantial urbanization in recent years; the Doha metropolitan area grew by approximately a factor of 8 between 1984 and 2020, while bare land was reduced by more than 50%. Recent Climate projections mark the Middle East as a climate change hotspot, making it an ideal region for studying urbanization and its implications. The distribution of the Urban heat island effect and its modification with urbanization over the tropical desert city of Doha, Qatar is investigated using high-resolution Weather Research and Forecasting (WRF-ARW) model simulations. Two fair weather cases corresponding to the winter and summer seasons during 2022 are considered for analysis. Four sets of simulations are conducted by modifying the land use land cover (LULC) data and urban parameterization schemes keeping all other physics options and configuration constant. The study includes the recent 100m hybrid CGLC-MODIS-LCZ dataset (Hybrid-LCZ data), which includes the global map of Local Climate Zones (LCZ), for the first time in the region. The simulations are (1) Comparatively older LULC data corresponding to the year 2001 (hereafter MODIS), (2) the current extensive urban area corresponding to 2018 coupled with a single-layer urban canopy model (UCM) (hereafter LCZ-UCM), (3) hybrid LCZ data coupled with multilayer Building Environment Parametrization (BEP) (hereafter LCZ-BEP), and (4) hybrid LCZ coupled with Building energy model (BEM) (hereafter LCZ-BEM). To the best of our knowledge, this is the first numerical analysis of the UHI effect over this region that includes simulations with the local climate zones (LCZ). The results indicate the presence of strong UHI intensity with a maximum of 4.5˚C (6.5˚C) during the winter (Summer) period. During late night and early morning hours, the urban heat island (UHI) effect is strong and during daytime, a strong urban cool island (UCI) effect dominates the region. During the winter period, the intensity of UHI and UCI are controlled by the prevailing synoptic wind systems. The amplitude of the UHI and UCI trend is reduced by the prevailing North Westerly winds, while the moisture-rich South Westerly winds enhance it. However, during summer the surface representation along with local weather patterns modulates the intensity of the UCI and UHI. A consistent improvement in the simulated meteorological parameters is noted from the simulation with MODIS, UCM, BEP, and BEM during the summer season. The LCZ-BEM model accurately simulates the urban heat island intensity, temperature, and relative humidity with minimal deviation from observations. However, in winter as the synoptic features play a crucial role in the surface conditions all model experiments show similar performance in comparison to the observations.    

 

How to cite: Jayarajan Roshini, R., Fountoukis, C., Siddique, A., Moosakutty, S., Alfarra, M., and Ayoub, M. A.: Numerical analysis of urban heat island in the coastal tropical desert city Doha, Qatar, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14514, https://doi.org/10.5194/egusphere-egu24-14514, 2024.

X5.175
|
EGU24-15276
|
CL3.1.1
|
ECS
David Donaire-Montaño, Feliciano Solano-Farías, Matilde García-Valdecasas Ojeda, Juan José Rosa-Cánovas, Emilio Romero-Jiménez, Yolanda Castro-Díez, María Jesús Esteban-Parra, and Sonia R Gámiz-Fortis

Convection-Permitting Models (CPMs) represent a crucial advancement in climate modeling, allowing for enhanced spatial resolution at convection scales (≤ 4 km). In convection-permitting simulations, various small-scale weather processes, notably microphysics and convection, play important roles. Evaluating the Weather Research and Forecasting (WRF) model's performance at convection scales becomes particularly pertinent in complex orography regions with substantial climate variability, such as Andalusia, in the southern part of the Iberian Peninsula (IP). To address this, convection-permitting simulations were conducted, focusing on the assessment of precipitation and 2-m temperature throughout the exceptionally wet year of 2018.

The simulations were based on two "one-way" nested domains: the parent domain (d01) covering the entire IP at 5 km spatial resolution and the nested domain (d02) covering the Andalusia region at 1 km spatial resolution. Implementing these simulations involved the exploration of 12 parameterization schemes, encompassing three microphysics (MP) schemes (THOMPSON, WRF single moment 6-class (WSM6), and WRF single moment 7-class (WSM7)) and four convection schemes for d01 (Grell 3D (G3), Grell-Freitas (GF), Kain-Fritsch (KF), along with the deactivated cumulus parameterization (OFF)). In the process of evaluating the model outputs, a comprehensive approach was adopted, using diverse observational datasets, including both gridded and station data. The comparisons were conducted on a point-to-point basis, considering various time aggregations (monthly, daily and hourly).

Main results show, on one hand, simulations employing the Grell-Freitas (GF) or deactivated cumulus parameterization (OFF) in d01 exhibited superior performance compared to reference datasets. On the other hand, while THOMPSON demonstrated a better fit in high mountain areas, it generally exhibited a poorer agreement with reference datasets than WSM6 and WSM7. In terms of temperature, the results displayed remarkable similarity, prompting the primary consideration of precipitation results. The WSM7-GF scheme emerged as the optimal configuration for the Andalusia region, underscoring its suitability in capturing the complex meteorological dynamics of this distinctive locale.

Keywords: sensitivity study, convection-permitting climate simulations, southern Iberian Peninsula, Andalusia, parameterization schemes, Weather Research and Forecasting model.

 

Acknowledgements:

This research has been carried out in the framework of the projects PID2021-126401OB-I00, funded by MCIN/AEI/10.13039/501100011033/FEDER Una manera de hacer Europa, P20_00035 funded by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades, and LifeWatch-2019-10-UGR-01 co-funded by the Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014–2020 (POPE) LifeWatch-ERIC action line.

How to cite: Donaire-Montaño, D., Solano-Farías, F., García-Valdecasas Ojeda, M., Rosa-Cánovas, J. J., Romero-Jiménez, E., Castro-Díez, Y., Esteban-Parra, M. J., and Gámiz-Fortis, S. R.: Evaluation of Weather Research and Forecasting Model Sensitivity to Different Physics Schemes in Convection-Permitting Mode over Southern Iberian Peninsula, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15276, https://doi.org/10.5194/egusphere-egu24-15276, 2024.

X5.176
|
EGU24-17506
|
CL3.1.1
|
ECS
|
Laura Detjen, Julia Curio, and Tinghai Ou

The Sichuan Basin (SB), a lowland region in southwest China located at the eastern slope of the Tibetan Plateau (TP), regularly experiences heavy and extreme precipitation events. These extreme events often lead to flooding that can pose a threat to life and livelihoods of people in this densely populated area. A notable example is the summer of 2020, during which large parts of East Asia were affected by anomalously high precipitation. In the SB, these events broke the previous record of daily accumulated rainfall at multiple stations.  

Since such events are expected to increase in both frequency and intensity in a warmer climate, understanding their causes and the physical processes involved is of high relevance in the SB region. Modelling the climate in mountainous regions with complex topography is challenging but recent developments in convection-permitting modelling make it possible to perform process-based studies.

The CORDEX Flagship Pilot Study Convection-Permitting Third Pole (CPTP) aims to improve our understanding of the water cycle over the TP and its surrounding regions using a multi-model ensemble of kilometre-scale simulations. Recent results using a set of CPTP simulations for one extreme precipitation event suggest that an accurate representation of the large-scale forcing is crucial to correctly simulate the event. In this study, we assess how well different kilometre-scale CPTP simulations capture multiple observed heavy and extreme precipitation events that occurred in the SB during the summer of 2020 by validating them against observations and reanalysis data. In addition, we analyse how the simulations differ among each other in representing the observed events and related important physical factors, e.g. large- and mesoscale circulation and moisture transport. A realistic representation of extreme events in climate models can provide a basis for more reliable future projections and uncertainty estimates.

How to cite: Detjen, L., Curio, J., and Ou, T.: Heavy and extreme precipitation events in the Sichuan Basin during the 2020 summer season in a set of kilometre-scale simulations, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17506, https://doi.org/10.5194/egusphere-egu24-17506, 2024.

X5.177
|
EGU24-18143
|
CL3.1.1
|
ECS
Eleonora Cusinato, Christoph Braun, Hendrik Feldmann, Beate Geyer, Klaus Keuler, Patrick Ludwig, Julia Moemken, Kevin Sieck, Katjia Trachte, Barbara Frühe, Christian Steger, and Joaquim G. Pinto

According to the latest assessment of the IPCC report, regional climate changes in mean climate and extremes are expected to become more widespread and pronounced. As a consequence, climate hazards are projected to increase in every region of the world leading to the necessity of developing climate adaptation and mitigation plans.  In this context, the German Federal Ministry of Education and Research (BMBF) funded several projects whose primary goal is to provide up-to-date regional and local climate projections that will subsequently form the bases for climate German adaptation strategies.

This contribution aims at illustrating ongoing research within the framework of two of these consortium projects, namely NUKLEUS (Usable Locale Climate Information for Germany) and UDAG (Updating the data basis for adaptation to climate change in Germany) to the EURO-CORDEX community. The innovative aspect of both projects lies in the creation of an unprecedented ensemble of convection permitting climate projections for “hydrological Germany" at high temporal and spatial resolution, which allows to provide information on climate change at regional and local scales.

For this purpose, NUKLEUS downscaled three global coupled models (GCMs) within the CMIP6 framework using three regional climate models (namely REMO, COSMO-CLM6 and ICON-CLM) first to the EURO-CORDEX Eur-11 domain (12 km) and subsequently to the km-scale at approximately 3 km resolution over Germany for the scenario SSP3-7.0. However, the resulting ensemble is not sufficient to provide actionable climate change information.
UDAG project aims at overcoming this limitation by downscaling a wide range of CMIP6-GCMs (6-8) using ICON-CLM first to 12 km resolution providing regional climate simulations for Europe for the scenarios SSP3-7.0 and SSP1-2.6 and then to approximately 3 km to generate climate projections specifically targeted for "hydrological Germany."

Given the shared use of common CMIP6-GCMs in the downscaling process for both projects, and considering the early stage of the UDAG project, this contribution presents initial insights from the NUKLEUS project. Biases evaluation analysis is conducted, revealing noteworthy distinctions in the RCMs at 12 km and 3 km compared to the CMIP6-GCMs. Subsequently, key metrics for extreme values statistics related to temperature and precipitation are discussed. In summary, these methods and findings serve as a preliminary groundwork for the forthcoming UDAG analysis.

 

How to cite: Cusinato, E., Braun, C., Feldmann, H., Geyer, B., Keuler, K., Ludwig, P., Moemken, J., Sieck, K., Trachte, K., Frühe, B., Steger, C., and Pinto, J. G.: Advancing regional to local climate knowledge: Insights from German NUKLEUS and UDAG Consortium Projects, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18143, https://doi.org/10.5194/egusphere-egu24-18143, 2024.

X5.178
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EGU24-19523
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CL3.1.1
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ECS
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Luna Santina Lehmann, Patricio Velasquez, Albert Ossó, and Christoph Schär

Previous studies predict an intensification of heavy precipitation events with climate change. These events are widely known to cause natural disasters with great property damage and loss of life, like flash floods or landslides. Knowledge about the scaling of precipitation, referring to the changes of precipitation intensity to warmer temperatures, is important for effective mitigation measures. Previous studies have investigated this scaling with regards to the Clausius Clapeyron relation, over various regions worldwide, using observational as well as model data. In this study we analyze the precipitation scaling over an orographically complex region as the Alps, as well as compare different methods to obtain the scaling rate.

To this end, we employ a 10-year multi-model ensemble of kilometer-scale convection-permitting climate model (CPM) simulations over the Greater Alpine Region from the CORDEX-FPS, with a spatial resolution ranging from 2.2 to 4 km. These simulations were obtained by downscaling global climate model (GCM) projections to intermediate regional climate models (RCMs), which were in turn further downscaled to kilometer scale by convection permitting climate models (CPMs). Previous work has shown the added value of these CPMs compared to lower resolution RCMs especially for extreme precipitation. We analyze these simulations over four alpine subdomains, which are characterized by different climatological characteristics.

In the calculation of precipitation scaling rates, we use two different precipitation indices, wet-hour percentiles and all-hour percentiles. These indices differ in that the latter encompasses all events, wet and dry, whereas the wet-hour percentile only includes events that go over a certain threshold. We compare the scaling calculated using these precipitation indices on an annual and seasonal basis, to show insights into the mechanisms that may cause scaling rates to exceed expectations given from the Clausius Clapeyron relation. Our results show that future precipitation intensity may be inferred from present-day scaling. The seasonal analysis shows scaling exceeding the Clausius Clapeyron scaling in the summer and autumn seasons for the wet-hour analysis, but not for the all-hour analysis.

How to cite: Lehmann, L. S., Velasquez, P., Ossó, A., and Schär, C.: Scaling of Precipitation in the Alps: Insights from a Convection Permitting Regional Climate Model Ensemble, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19523, https://doi.org/10.5194/egusphere-egu24-19523, 2024.

X5.179
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EGU24-1873
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CL3.1.1
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ECS
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Highlight
Stephanie Haas, Gottfried Kirchengast, and Jürgen Fuchsberger

Short-duration extreme convective precipitation events (SDECPEs) are increasingly altered by climate change. Considering their severe risk, and high impact on our everyday lives, a profound understanding of such extreme precipitation is crucial. For their investigation we can leverage a newly developed class of Threshold-Exceedance-Amount (TEA) metrics, which enable the detection and tracking of weather and climate extremes. The compound indices based on these TEA metrics have proven to be a useful tool to investigate changes of different characteristics of temperature and precipitation extremes, both in isolation and in combination.

It is challenging, however, to perform such an analysis for SDECPEs, since their short durations of only about one to three hours and their highly localized character make them very weakly detectable in reanalysis datasets like ERA5-Land, with a spatial resolution of the order of 10 km (0.1° x 0.1° grid). High resolution datasets like from the WegenerNet climate station network in southeast Austria (100 m x 100 m, 5 min) and GeoSphere Austria’s INCA dataset (1 km x 1 km, 15 min) are far better suited for this purpose but offer only data over the most recent two decades. To our knowledge, there is currently no dataset that on its own fulfills all three key requirements (high spatial resolution, high temporal resolution, long data record) for the analysis of SDECPEs over time.

To get observations-based insight into the influence of climate change on SDECPEs in the southeast Alpine forelands, in particular their possible amplification, we aimed to bypass and overcome the weaknesses of any single dataset by a study consisting of two parts: (1) the high-resolution exploration of SDECPEs in the well-observed most recent two decades. Here we investigate the relationship between maximum hourly precipitation and average hourly precipitation on SDECPE-days and complement our findings with information about the temperature increase in the study region. (2) We perform a longer-term assessment of the development of SDECPEs based on reanalysis data. Using the knowledge gained from (1), we are able to model maximum hourly precipitation data and compare the changes in event characteristics to the ones of daily precipitation sums.

We show that our approach does reveal some evidence for a climate change induced amplification of SDECPEs in the southeast Alpine forelands. At the same time, the results vary strongly within the study region, mainly due to high natural variability.

How to cite: Haas, S., Kirchengast, G., and Fuchsberger, J.: Exploring the climate change influence on short-duration convective precipitation extremes in the southeastern Alpine forelands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1873, https://doi.org/10.5194/egusphere-egu24-1873, 2024.

X5.180
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EGU24-19237
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CL3.1.1
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ECS
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Emilio Greciano-Zamorano, Jesús Fidel González-Rouco, Cristina Vegas-Cañas, Félix García-Pereira, Jorge Navarro-Montesinos, Elena García-Bustamante, Esteban Rodríguez-Guisado, and Ernesto Rodríguez-Camino

Mountain areas are particularly sensitive to global warming as they usually present a complex distribution of climates and ecosystems and feedbacks tend to amplify the effects of climate change. Additionally, the large spatial variability of temperature gradients and heterogeneity in the occurrence, amount and distribution of precipitation and snow cover in mountainous areas are especially relevant for water resources and stresses the need for high altitude observations and high-resolution modelling over complex terrain. However, harsh meteorological conditions and the complex orography associated with this environment that, as part of the Mediterranean domain, has been underscored as a climate change hot-spot, hinder the obtention of a good coverage of high-altitude observations and pose challenges for regional climate models.

CIMAs is a joint effort aiming at improving our understanding of climate variability over mountain regions in Iberia. A pilot area has been selected over the Sierra de Guadarrama (Spanish Central range, about 50 km from Madrid) aiming at studying climate variability through very high (1 km) resolution simulations, exploring models’ ability to capture relevant processes at that scale. A set of observational sites ranging from high altitudes to low levels at both sides of the mountain range has been used.

ERA Interim, ERA5 and different WRF nested simulations, spanning the last three decades and reaching 1 km resolution, have been compared to a dense network of in situ observations. Results show a clear improvement with increasing resolution for temperature, but some altitude-related biases for precipitation. In this sense, some sensitivity tests to changing convection parameterizations and to convection permitting configurations have been assessed.

How to cite: Greciano-Zamorano, E., González-Rouco, J. F., Vegas-Cañas, C., García-Pereira, F., Navarro-Montesinos, J., García-Bustamante, E., Rodríguez-Guisado, E., and Rodríguez-Camino, E.: Climate Initiative for Iberian Mountain Areas (CIMAs): improving our understanding of climate variability over mountain areas using high resolution modelling., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19237, https://doi.org/10.5194/egusphere-egu24-19237, 2024.