• Land-atmosphere interactions and hydrological processes, including feedback mechanisms.
• Understanding the meteorological processes driving hydrological extremes.
• Tools, techniques, and expertise in forecasting hydro-meteorological extremes (e.g., river flooding, flash floods, droughts etc.).
• Fully integrated numerical earth system modelling.
• Quantification/propagation of uncertainties in hydro-meteorological model forecasts.
• The role of vegetation in hydro-meteorological extremes, in terms of transpiration, photosynthesis, phenology, etc.
• Energy cycles, complementing the hydrological cycles and related cryospheric processes.
• Hydro-meteorological prediction that includes impacts.
• Environmental variable monitoring by remote sensing and other observations.
• Quantification of (past/future) hydrological trends in observations and climate models (and their role in the 2024 "climate-neutral Europe" conference theme).
The diverging trends in annual soil moisture across Europe are stark: Northern regions are increasingly wet, while Southern areas face growing aridity, largely due to contrasting precipitation patterns between these regions. While several studies have examined the consequences of soil moisture deficits and drought in the south, the implications of increasing soil moisture levels in the north remain less explored. This study leverages reanalysis products, such as ERA5-Land, to delve into the soil moisture dynamics of Northern Europe, examining seasonal and sub-seasonal trends across the period 1951-2020. This research includes both a detailed case study of Denmark, and an analysis focusing on the Northern European domain. A primary hypothesis is that spatiotemporal soil moisture trends are influenced not only by changes in mean precipitation, but also by altered temporal patterns of rainfall at sub-seasonal scales across the domain. Moreover, increased soil moisture persistence during the wet season heightens the risk of complex and compound hydro-meteorological interactions between saturated soils and intense rainfall events. The analysis also uncovers a north-to-south soil moisture gradient within Northern Europe, particularly evident with spring drying (MAM). In the southern parts of Northern Europe (including Denmark, southern Sweden, and the Baltic region) this manifests as a wetting trend in winter (DJF) and a drying trend in spring (MAM), posing challenges for water management across sectors. The findings of this study underscore critical research areas requiring further investigation, such as the impacts of increasing soil moisture and more frequent intense rainfall events on streamflow and flooding. Future research could benefit from employing hydrological models to explore these dynamics in greater detail.
How to cite: Newell, M., Drews, M., Payne, M., and Larsen, M. A. D.: A Northern European paradox: both wetting and drying trends complicate water management , EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-698, https://doi.org/10.5194/ems2024-698, 2024.
There are large uncertainties in the future evolution of water resource availability over western and central Europe. This availability, characterized by total runoff, is the result of two driving variables, precipitation and evapotranspiration. The signal-to-noise ratio for changes in precipitation is low. Changes in evapotranspiration are strongly influenced by uncertainties associated with the modelling of land-atmosphere interactions.
Here we highlight the diverging hydrological behavior of models from the 6th phase of the Coupled Model Intercomparison Project over western and central Europe. Some models project a marked decrease in runoff in the late 21st century while others simulate no change or a slight increase. The decrease in runoff is driven either by a decrease in precipitation and evapotranspiration or by an increase in precipitation and an even larger increase in evapotranspiration. The mechanisms responsible for the inter-model spread are investigated with experiments from the Model Intercomparison Project on Land Surface, Snow and Soil Moisture (LS3MIP, van den Hurk et al. 2016) and on the coupled Climate-Carbon Cycle (C4MIP, Jones et al. 2016). The change in large-scale atmospheric circulation is shown to be an important driver of the inter-model spread in precipitation changes in winter. In summer, the physiological effect of CO2 has a direct influence on evapotranspiration and precipitation changes. Models with a strong biogeochemical effect of CO2 show a strong decrease in evapotranspiration and precipitation in summer.
The potential relationship between the mean present-day state and trends, and the inter-model spread in the future changes in the hydrological cycle projected by the CMIP6 models is also examined. The models that project a large decrease in runoff are often associated with a large climatological value of evapotranspiration. Among them, some models also show strong positive trends in precipitation and evapotranspiration that are consistent with their future response at the end of the 21st century. However, it remains difficult to judge the realism of models on the basis of this assessment alone, in particular due to large observational uncertainties.
van den Hurk et al.: LS3MIP (v1.0) contribution to CMIP6: the Land Surface, Snow and Soil moisture Model Intercomparison Project – aims, setup and expected outcome, Geosci. Model Dev., 9, 2809–2832, https://doi.org/10.5194/gmd-9-2809-2016, 2016.
Jones, C. D et al.: C4MIP – The Coupled Climate–Carbon Cycle Model Intercomparison Project: experimental protocol for CMIP6, Geosci. Model Dev., 9, 2853–2880, https://doi.org/10.5194/gmd-9-2853-2016, 2016.
How to cite: Deman, J. and Boé, J.: Investigating the large uncertainties in future changes in runoff over western and central Europe, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-174, https://doi.org/10.5194/ems2024-174, 2024.
Increasing urbanisation and climate change have had a significant impact on urban infrastructure due to the expansion of impervious surfaces. These surfaces lead to excessive runoff, which strains urban drainage systems beyond capacity and often causes damage. Traditional rainfall-runoff models often fail to adequately reflect the specific characteristics and limitations of urban pipe networks. These models typically use the Curve Number (CN) method to categorise land into eight types, including urban areas. This method primarily addresses surface and subsurface runoff without considering important urban infrastructure components such as drainage pipes and storage facilities. Recognising these shortcomings, this paper presents a new concept of distributed rainfall-runoff model, called S-RAT Urban, which incorporates the urban pipe network in the watershed analysis. The model incorporates both temporal and spatial variability of hydrological processes to improve the accuracy of runoff prediction. The model uses a distributed approach that applies the curve number method to better represent urban environments, including the effects of overlooks. The model uses a grid-based input system that uses Digital Elevation Models (DEMs), land use and soil type data to generate flow directions. The traditional two-dimensional (2D) flow direction mapping used in urban areas is converted to a one-dimensional (1D) pipe network model. This conversion is critical to realistically simulate flow through urban drainage systems. In addition, flow within the pipe network is calculated using continuous and impulse equations to provide a dynamic and realistic representation of the urban hydrological response under different weather conditions. This method not only identifies the variability of the hydrological cycle under natural conditions, but also incorporates critical urban infrastructure into the distributed model, providing a more comprehensive and practical tool for urban catchment management.
How to cite: Lee, D. and Kim, B.: Development of the 2D/1D Coupled S-RAT Model for Flooding Simulation Dual Drainage in watershed, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-708, https://doi.org/10.5194/ems2024-708, 2024.
River routing models are important tools to document, anticipate and forecast river flows dynamic, and perceive the evolution of water resources in the context of climate change. The performance of these models can evolve through different methods, including resolving more complex physical equations, refining the model spatial resolution, improving the model parametrisation, the hydrological network, the forcings. Our study focuses on the impact of more or less complex physical equations and numerical solutions on the performances of the routing model CTRIP.
The CTRIP model (CNRM version of the Total Runoff Integrated Pathways) is the river routing model developed at the CNRM, at Météo France. It converts the runoff simulated by the ISBA (Interaction Sol Biosphère Atmosphère) land surface model into river discharge (http://www.umr-cnrm.fr/spip.php?article1092). It is used for many hydrological applications at medium and large scales. ISBA-CTRIP is the hydrological component of the CNRM climate models, and allows to close the water budget at the global scale. CTRIP handles the horizontal transfer of water over continental surfaces, and describes the main processes of the continental water cycle. In particular, it describes the water propagation into the river network.
Currently, CTRIP simulates the propagation of river discharges using the kinematic approximation of the Saint-Venant equations, in a uniform regime. The equation of water mass conservation is used with the water velocity deduced from Manning's equation. The river is described as a single prognostic reservoir whose discharge is linearly related to the river mass [Decharme 2010]. This simple scheme is adapted to low resolutions, but reaches its limits if the resolution needs to be increased. Going to higher resolutions would allow to better represent dynamic phenomenons, and to take into account small scale processes. It would allow a better representation of the hydrological network, and could result in a quality upgrade for the CNRM hydrological productions. Our study aims to go further the simplistic representation of discharge propagation in rivers into CTRIP and to reach a more complex approach.
In our works, many approximations of the Saint Venant equations are studied : the kinematic approximation in a non uniform regime [Yamazaki 2011], the local inertial approximation [Bates 2010], the diffusive approximation [Moussa 1996], and the dynamic approximation. Several numerical methods are used to solve them : Euler, Crank-Nicholson, Gauss-Seidel. It is coded in CTRIP with a 1/12° spatial resolution (~ 8 km at medium latitudes), in offline mode [Munier 2022] over the Adour basin in South-West of France. CTRIP is forced by total runoffs from the hydrometeorological chain SIM2 (https://www.drias-eau.fr/accompagnement/sections/305) [Le Moigne 2020]. The different versions of the model are compared to a full Saint Venant model, for theorical validation. They are also compared to a dense in-situ network of discharge observations.
How to cite: Peronnet, E., Decharme, B., and Munier, S.: Comparison of numerical solutions for the flow wave propagation in river networks, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1044, https://doi.org/10.5194/ems2024-1044, 2024.
An aspect of hydrologic sensitivity to climate change in snow dominated systems that has been moderately explored relates to the role of snowfall and snowpack accumulation in storing water throughout cold season months and releasing this water to terrestrial systems during warmer months when potential evapotranspiration (PET) is relatively elevated. Importanlty, previous studies have not been able to document an explicit mechanism linking precipitation type to runoff production; yet several studies have noted that a sensitivity does exist. Given that a shift from snowfall to rainfall is inevitable as the climate warms, this fundamental question as to how streamflow responds to a change in precipitation type is extremely timely and important for water resource management. Hence, one would expect that climate-related shifts toward earlier snowmelt or a shift from snowfall to rainfall would lead to an increased misalignment between the seasonality of surface water input (i.e. rainfall and snowmelt) and PET, and thus act to decrease annual partitioning to evapotranspiration and increase annual streamflow. This shift from snowfall to rainfall, and it's associated influence on hydrologic partitioning will be refered to below as the 'energy-water-misalignment perspective'. A second hypothesis, that is counter to the energy-water-misalignment perspective, has documented an increase in runoff partitioning with increased snowfall fraction which relates to a theorized greater effiency of soil-water drainage from snowmelt versus rainfall due to the high rate and duration of snowmelt; hereafter referred to as the 'snowmelt-rate perspective'. In pursuit of this line of inquiry, this presentation will cover recent modeling and observation-based experiments that reveal the importance of both of the aforementioned runoff response perspectives. The combination of these modeling and observation-based studies confirm that the energy-water misalignment perspective and the snowmelt-rate perspective both influence hydrologic partitioning sensitivity to precipitation type. The resultant streamflow sensitivity to precipitation type and climate warming is therefore complex with the sign of the partitioning sensitivity being governed by the relative importance of the two paradoxical runoff response perspectives presented herein.
How to cite: Molotch, N.: The influence of precipitation type on snowmelt partitioning between evapotranspiration and streamflow, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-930, https://doi.org/10.5194/ems2024-930, 2024.
Future climate change is expected to exacerbate hydrological drought in many parts of Europe, making effective management of water resources more imperative to ensure groundwater sustainability. The EU biodiversity strategy for 2030 suggests a strategic target to turn at least 10% of the EU's agricultural areas into high-diversity landscape features like hedges and trees.
In this study, we investigate how afforestation would affect hydrological conditions in Europe under climate change, focusing on three scenarios: (1) a hypothetical extreme scenario transforming all agricultural land into forests under the current climate, (2) a more realistic scenario aligning with the EU biodiversity strategy which envisages converting 10% of the land under the current climate, and (3) a scenario involving the conversion of 10% of agricultural land into forests, but under a climate that is 2°C warmer.
We use the LISFLOOD hydrological model setup across Europe at a spatial resolution of ~2km forced by gridded observed precipitation and temperature over a period of 1991-2020 under current climate. The results were evaluated as changes in evapotranspiration, groundwater levels, and river discharge peaks against a benchmark run. The findings from the afforestation scenario indicated a rise in evapotranspiration, higher groundwater levels, and diminished river flow peaks, suggesting an improvement in water sustainability as well as increased resilience to flooding. This study highlights the hydrological benefits of strategic land use changes, offering key insights for European water resource management and policy formulation in the face of climate change. It also offers a potential toll for decision makers to tackle affects of climate change.
How to cite: Wetterhall, F. and El Garroussi, S.: Data-driven selection of optimal afforestation sites in Europe for drought adaptation , EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1056, https://doi.org/10.5194/ems2024-1056, 2024.
The intensification of extreme precipitation in a warming climate has been shown in observations and climate models to follow approximately theoretical Clausius-Clapeyron scaling. However, larger changes have been indicated in events of short-duration which frequently trigger flash floods or landslides, causing loss of life. Global analyses of continental-scale convection-permitting climate models (CPCMs) and new observational datasets will be presented that provide the state-of-the-art in understanding changes to extreme weather (rainfall, wind, hail, lightning) and their compounding effects with global warming. These analyses suggest that not only warming, but dynamical circulation changes, are important in the manifestation of change to some types of extreme weather, which must be addressed in the design of new CPCM ensembles. We use our projections to provide the first analyses of impacts on infrastructure systems using a new consequence forecasting framework and show the implications for adaptation. It will be argued that a shift in focus is needed towards examining extreme weather events in the context of their ‘ingredients’ through their evolution in time and space. Coupled with exploration of their causal pathways, sequencing, and compounding effects – ‘storylines’ –, this can be used to improve both early warning systems and projections of extreme weather events for climate adaptation.
How to cite: Fowler, H.: Rapidly intensifying extreme weather events in a warming world: how important are large-scale dynamics in generating extreme floods?, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1052, https://doi.org/10.5194/ems2024-1052, 2024.
Flash floods, or rapid response catchment flooding, can be defined at flooding impacts between 0-6 hours of impactful rainfall occurring. Nowcasting can be defined at the 0-2 or 0-6 hour time scale. To save lives, warnings at these very short lead times, whether they are for urban areas or ravines, need to be issued rapidly to a receptive customer base.
The Met Office Expert Weather Hub (formally guidance unit) is operating a surge capacity this summer drawing on rapidly updating diagnostics to identify areas of intense convection and flood producing rainfall, as well as other hazards.
At the same time, the Flood Forecasting Centre (FFC) is piloting a Rapid Flood Guidance Service where days 1 and/or day 2 of the daily Flood Guidance Statement are highlighted as susceptible to rapid flooding. This will highlight potentially affected areas of England and Wales to emergency responders. Using the detailed output from the Expert Weather Hub, the FFC will issue Rapid Flood Guidance to emergency responders at short lead times, less than 6 hours, and possibly less than 2 hours’ notice.
In addition, the Met Office are running a summer forecasting testbed which will explore two rapid surface water flooding hazard impact models. The Surface Water Flooding Hazard Impact Model, SWFHIM, was developed through the Natural Hazards Partnership and is currently used operationally in the FFC. The second, FOREWARNS, has been developed by the University of Leeds and the Met Office.
This presentation will explain the components of the Rapid Flood Guidance trial and present key findings from research to operations, as well as a summary of the evaluation from the hundreds of emergency responders who have already signed up for the trial. It will also highlight key findings from the evaluation of the surface water impact models, with a focus on less than 24 hours lead time. We will highlight development areas to the science and operational development, and suggest how such short notice warnings can best be communicated to potential users to incite the appropriate actions.
How to cite: Pilling, C., Wynn, A., Turner, R., and Maybee, B.: Rapid Flood Guidance for flash floods – a trial service for England and Wales, summer 2024, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1105, https://doi.org/10.5194/ems2024-1105, 2024.
Flash floods are one of the most devastating natural hazards. Every year, they cost thousands of lives and millions of dollars in damaged infrastructure. They can occur in large or small catchments, rural or urban areas, close or away from rivers, and with little to no warning. Some regions might have adapted to protect infrastructure and people against this hazard; however, with climate projections suggesting that extreme rainfall might increase in intensity and frequency, "residual risk" might increase in protected areas while unprotected ones might experience unseen severe losses. Hence, relying on medium-range forecasts that offer good predictions of areas at risk of flash flooding with enough lead time to extend preparedness and action time windows is becoming increasingly important.
This presentation will showcase the most recent developments in the prediction of flash floods over a continuous global domain up to medium-range lead times. We will start by describing the system (ecPoint) used to create the rainfall-based flash flood predictions (ecPoint-Rainfall forecasts) and the warning thresholds that identify areas at risk of flash floods (ERA5-ecPoint rainfall reanalysis). We will also present long-term objective verification results that benchmark our rainfall-based flash flood predictions against competing rainfall forecasts, e.g. ECMWF ensemble forecasts. Through the presentation of case studies, we will explore the added value of using our proposed forecasts in case of low-probability but high-impact flash flood events. We will finally provide practical guidance and recommendations on how to use the flash flood predictions to enable decision-makers to extend their preparedness and action time window.
How to cite: Pillosu, F., Clare, M., Haiden, T., Pappenberger, F., Prudhomme, C., and Cloke, H.: Can we now predict flash floods globally and up to medium-ranges?, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1064, https://doi.org/10.5194/ems2024-1064, 2024.
Meteorological forecasts are crucial for mitigating extreme weather impacts, but they always contain sources of uncertainty. One of these arises in the prediction of the location of intense convective precipitation systems: this issue is particularly critical for flood forecasting in small watersheds, where even a slight discrepancy in the predicted rainfall location can lead to significant inaccuracies in flow forecasts.
In this study, we propose a methodology for quantifying the spatial biases of rainfall forecasts produced by the MOLOCH meteorological model on the hydraulic node of Milan (northern Italy), which is a strongly urbanized and sensible territory due to the presence of productive activities, critical infrastructures and more than 4 million inhabitants. The goal is to investigate whether the model exhibits “preferential” directions where it tends to misplace convective precipitation events.
A total of 65 significative convective rainfall episodes were selected during the 2013-2022 period, comparing the rainfall forecasts at day+0 with the observed rainfall field obtained through a merging of radar and rain-gauge stations (“PRISMA” dataset, provided by Lombardy Region’s Civil Protection).
The proposed procedure relies on the definition of a domain around the study area which is suitable to define the eastwards/northwards spatial misplacements of the forecast rainfall field, such domain was defined accordingly to an analysis on the Fractional Skill Score (FSS).
Results indicate that the MOLOCH meteorological model tends to misplace convective rainfall systems towards the North-West and North-East directions, and this outcome could be significant to forecasters operating in the civil protection sector, especially for these river catchments with limited spatial extent.
How to cite: Gambini, E., Ravazzani, G., Mancini, M., Valsecchi, I. Q., Cucchi, A., Negretti, A., Davolio, S., and Ceppi, A.: Assessing spatial biases of a meteorological model for real-time flood forecasts in the hydraulic node of Milan, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-911, https://doi.org/10.5194/ems2024-911, 2024.
The study of precipitation due to convective phenomena is one of the most challeging tasks in climate and meteorological research and especially from the perspective of collected surface precipitation since they can lead to natural disasters in various regions, impacting entire populations. This work aims to classify convective phenomena after identifying them based on a methodology that separates precipitation components into convective and stratiform.
Based on statistical properties of precipitation, a threshold value, or critical precipitation ratio, has been computed in order to classify every precipitation event into a stratiform or convective episode. The criterion to identify a convective phenomenon consists of knowing if rain rate exceeds such critical value. Rain events, particularly convective ones, may vary in intensity, duration, and frequency depending on the climatic zone, and thus they will be categorized according to these areas.
To conduct this study, precipitation data, both hourly and daily measurements, from surface rain gauge stations have been utilized. These data cover all of Peninsular Spain and Balearic Islands from 1998 to 2023 and have been provided by Aemet (the Spanish Meteorological Agency).
Previous findings indicate that convective episodes occur less frequently in the Eastern Iberian Peninsula compared to the Cantabrian area. However, they exhibit shorter duration and higher maximum rainfall intensity in the former. Despite these variations, the accumulated precipitation amounts per episode and per station are similar in both regions. Furthermore, it is noted that the number of rain gauge stations affected by convective phenomena is greater in the Cantabrian area, suggesting a broader distribution of these episodes in the northwest of Spain. It hints at potential atmospheric and geographical factors influencing convective processes in different parts of Spain.
How to cite: Ruiz-Leo, A. M., García de Arboleya, J. L., and González Payo, J.: Classification of convective episodes in different climatic zones, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-214, https://doi.org/10.5194/ems2024-214, 2024.
In order to further develop an ICON-based, storm-resolving earth-system model, the ParFlow hydrological model has been coupled to the ICON land component, which is based on the JSBACH land surface model. The overall goal is to better capture land-atmosphere interactions ensuring balanced water and energy budgets in global, kilometer-scale simulations on the climate time scale. Compared to the JSBACH hydrology, ParFlow allows a variable subsurface thickness and 3D groundwater dynamics in connection with resolved overland flow in a continuum approach. In combination with the two-way feedback between atmospheric and hydrological processes provided by the coupling, this is expected to resolve hydrological processes more realistically in space and time. Technically, the YAC coupling library has been used to account for horizontal grid differences and different spatial and temporal resolutions in ICON and ParFlow.
In the proposed global setup, ParFlow has been implemented over a European domain with a subsurface depth of 60 m to account for deeper aquifers. Thus, 3D groundwater dynamics and two-way-coupling with the land surface and atmosphere is active only over that specific region of interest while the rest of the global land surface relies on the default hydrological model of JSBACH. This way, no atmospheric boundary data needs to be provided in contrast to regional weather and climate model setups so that a closed representation of the global water cycle can be established including regional feedbacks with groundwater. In addition to a general proof-of-concept, our presentation provides a first analysis of moisture distribution and land-atmosphere fluxes both inside and outside the coupling region as well as potential feedbacks of groundwater on the atmospheric circulation and large-scale weather patterns beyond the regional scale.
How to cite: Weinkaemmerer, J., Schnur, R., Goergen, K., and Kollet, S.: Integrating the ParFlow hydrological model into ICON, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-260, https://doi.org/10.5194/ems2024-260, 2024.
Water is a key socio-economic factor (e.g. drinking water, sanitation, irrigation, energy) affecting the main challenges of this century. Therefore, it is important to analyse the projected regional hydrological changes related to climate change. The estimated trends may help to build and implement appropriate adaptation strategies in water-management (including flood defence and water storage) in order to mitigate the potential hazards.
In the present study, the estimated changes of water discharge are analysed at four cross-sections (i.e. Tiszabecs, Mizshirja, Uszti Csorna, Rahiv) in the Uppest-Tisza Basin, located in Eastern-Central Europe. For the investigation, the DIWA (Distributed Watershed) hydrological model is applied, while the necessary meteorological input data (daily minimum and mean temperature, precipitation) were provided by the CARPATCLIM database for the historical period (1972–2001) and by a regional climate model simulation for the future (2069–2098), taking into account two different RCP scenarios (RCP4.5 and RCP8.5). In order to eliminate the systematic errors of climate model simulations, a bias-correction is completed by adjusting the parameters of the distribution of temperature, dry and wet spells and precipitation amount. The correction factors are determined by the differences between the reference database and the historical climate model simulation. Furthermore, to take into account all the possible changes, the DIWA simulations are embedded in a Monte Carlo cycle, hence, several hundreds of possible realisations of water discharge values can be investigated.
According to our results, higher temperature values are likely to occur in the target area by the end of the 21st century, and winter precipitation is projected to increase. The mean water discharge is projected to decrease from April to September in the case of RCP4.5, and from March to October in the case of RCP8.5, while in January and February an increase is likely to occur.
Acknowledgements: Research leading to this study has been supported by the Hungarian National Research, Development and Innovation Fund (under grants PD-138023 and K-129162), and the National Multidisciplinary Laboratory for Climate Change (RRF-2.3.1-21-2022-00014).
How to cite: Pongracz, R., Kis, A., and Szabó, J. A.: The effects of climate change on the essential characteristics of catchment runoff in the Uppest-Tisza Basin, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-620, https://doi.org/10.5194/ems2024-620, 2024.
Condensed water path (CWP) is the sum of liquid water path (LWP) and ice water path (IWP). CWP is an essential parameter affecting a wide range of atmospheric processes including cloud properties, precipitation formation and both short and long wave radiation properties of the atmosphere. Therefore, it is desirable to validate this quantity in both global and regional model outputs and to quantify its impact on other climate characteristics. Finally, this knowledge could help to understand differences between CMIP5 and Euro-CORDEX climate simulations as they are discussed among modelers and climate change impact communities and lead to better representation of physical process in climate models.
We focused on the area of Central Europe and recent climate and its projection according to scenarios RCP 4.5 and SSP-2.45. We have selected all model simulations containing CWP available from Euro-CORDEX initiative and CMIP5 and CMIP6 over Europe. CWP data were then aggregated for each of the 4 distinct ensembles (Euro-CORDEX high resolution, Euro-CORDEX low resolution, CMIP5 and CMIP6) in monthly time step and then compared to observations represented here by ERA5 re-analysis and CLARA 2.1 satellite measurements data.
We have found that ERA5 and CLARA data agree well with each other. CWP available from CORDEX models and represented as ensemble mean is then significantly underestimated compared to the reanalysis, observation dataset and both CMIP ensemble means. CMIP5 models processed in the same way as CORDEX models then overestimate CWP compared to reanalysis and observations, whilst CMIP6 ensemble offers the best agreement with observed data. The future climate projections based on RCP 4.5 scenarios (CMIP5 and CORDEX models) and SSP-2.45 (CMIP6) models were also assessed. CMIP6 models then project statistically significant loss of CWP over the 21st century, CMIP5 data and CORDEX data project strong increase in CWP. However, values from both CORDEX ensemble means by the end of the century are still not reaching the levels from observed data.
How to cite: Penčevová, R., Farda, A., Meitner, J., Skalák, P., Štěpánek, P., and Zahradníček, P.: Condensed water path in GCMs and RCMs simulations over Europe , EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-817, https://doi.org/10.5194/ems2024-817, 2024.
Moisture tracking is a technique to characterize the transport of moisture in gridded atmospheric datasets. It enables users to map source and sink region of (extreme) precipitation or evaporation, respectively. With intensifying wet and dry extremes, the interest in moisture tracking has grown substantially over the past decade.
Various models are used for moisture tracking today. They differ in their approach (Lagrangian versus Eulerian), complexity, input data, assumptions, et cetera. The lack of ground truth data makes it challenging to interpret the results, especially where different approaches lead to different moisture tracking results.
To facilitate comparison between models, it is helpful if both models and their input/output data adhere to best practices for reusable and reproducible data and software. In the development of WAM2layers V3, we have made good progress in incorporating such (FAIR) standards. For example, the WAM2layers software is easy to find and install, well documented, has a DOI, and follows semantic versioning standards. Input data for example cases is available as well, also with a DOI, and a download utility is part of the software so one can get started in minutes. Similarly, the output data adheres (as much as possible) to CF-conventions and adds all relevant metadata, to maximize the reusability and reproducibility of the results.
In May of 2024, users and developers of various moisture tracking models will gather in Leiden to analyse the results of the first community moisture tracking intercomparison study. This is a first step towards better understanding of the effects of certain modelling choices and to address the uncertainty among different models. At EMS, we will showcase our WAM2layers contributions to the Lorentz intercomparison study to demonstrate how the incorporation of data and software best practices in WAM2layers contribute to a FAIR and reproducible moisture tracking workflow.
How to cite: Kalverla, P., Benedict, I., van der Ent, R., Weijenborg, C., and Schilperoort, B.: FAIR and reproducible moisture tracking with WAM2layers V3, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1032, https://doi.org/10.5194/ems2024-1032, 2024.
Irrigation plays a crucial role in maintaining an ideal soil moisture level for an optimal crop development. This practice is nowadays indispensable for farmers as a method to adapt to the challenges posed by climate change. The Earth science community has recognized additional effects of irrigation beyond its impact on soil moisture and plant growth. Various studies have revealed that irrigation can influence atmospheric variables such as 2-meter temperature, relative humidity, and even precipitation. Furthermore, researchers have investigated the impact of irrigation on the Earth's system across different timeframes, geographic regions, and using diverse climate and land surface models. Nevertheless, the number of studies that have simulated the effects of irrigation at higher resolutions on a regional level are scarce. Therefore, the aim of this study is to include the representation of irrigation processes in the operational ICON-nwp in Limited Area Mode on the EURO-CORDEX domain at 3km resolution. The implementation of the current irrigation parameterization in ICON-nwp coupled with TERRA is an adaptation of the CHANNEL scheme developed by Valmassoi et al. (2020). Since there are more than one land surface model coupled with ICON, we found suitable to include this scheme in the land surface and atmosphere interface of the icon-nwp-2.6.6-nwp0 version.
The current investigation includes two irrigation maps: the default map from the operational ICON-nwp (from GlobCover2009) and the Digital Global Map of Irrigation Areas (Siebert, et al. 2013). For the first irrigation map, the study comprises five sensitivity experiments involving varying irrigation water amounts: 2.6 mmd-1, 6.7 mmd-1, 11.1 mmd-1, and two fixed soil moisture levels (field capacity and saturation). Regarding the second irrigation map, currently we have three experiments with the irrigation amounts: 2.6 mmd-1, 11.1 mmd-1, and soil moisture set to field capacity. All experiments have the same irrigation frequency (1 day), length (24 hours), and simulation period (May to August). The results from the difference between experiments and the control run demonstrate that ICON captures the irrigation effect on land surface atmospheric variables. As expected, soil moisture content increases resulted in an average cooling effect of 1.4 K across all experiments. Likewise, energy fluxes were sensible to the different irrigation quantities. In addition, we present a validation of selected irrigation experiments with a reanalysis dataset and observations from meteorological stations used in the operational DWD model equivalent cycle. Preliminary results indicate that when comparing the biases of the first guess with those of the field capacity experiment concerning observations in Spain, the temperature bias decreases from an average of -0.20 to -0.08 across twelve stations.
How to cite: Roque, J., Valmassoi, A., and Keller, J.: Impact of Spatial Extension of Irrigation in the ICON-nwp Model, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1058, https://doi.org/10.5194/ems2024-1058, 2024.
The Northeast China maize belt is one of the three major golden maize belts in the world and has been severely affected by climate changehowever, the evapotranspiration(ET) partitioning is not clear. It is important to study ET and its components under climate change. In this paper, the water balance model SOILWAT2 was used to estimate ET partitioning in drought and humid years, seasons, and maize growth stages from 1989 to 2018 over rainfed maize farmland. The results indicated that the SOILWAT2 model performed well for the prediction of ET and its partitioning compared with eddy covariance measurements. The mean yearly ET, transpiration (T), soil evaporation (Es), and canopy interception evaporation (Int) were 432.3 mm, 197.6 mm, 204.7 mm and 19.2 mm, respectively, over 30 years. Es/ET was 6.3% lower in drought years than in humid years, T/ET was conversely higher (6.2% higher in drought years). There was no clear difference of Int/ET between humid and drought years. In the growing season, T/ET, Es/ET, and Int/ET varied from 40.0% to 75.0%, 22.8% to 55.7%, and 0.7% to 7.0%, respectively. T/ET decreased along with the growth of maize and was greatest at the greening–jointing stage. Es/ET was smallest at the greening–jointing stage. We found a power function relationship between T/ET, Es/ET, and leaf area index (LAI) and above-ground biomass. Our results indicated that for the rainfed farmland, drought may limit maize yield by increasing water loss of maize through increasing T under climate change conditions. Therefore, securing food yield will depend on increases in water-use efficiency and other adaptive strategies, such as drought-resistant varieties, and irrigation.
How to cite: Chen, N., Schlaepfer, D. R., Zhang, L., Lauenroth, W. K., Mi, N., Ji, R., and Zhang, Y.: Evapotranspiration Partitioning using a Process-Based Model over a Rainfed Maize Farmland in Northeast China, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-35, https://doi.org/10.5194/ems2024-35, 2024.
