According to the latest IPCC report (2023), the Mediterranean region faces already significant risks like heatwaves, water scarcity, droughts, coastal risks due to flooding, erosion, wildfires and human health due to climate change. Taking into consideration that the Mediterranean region experiences air temperature almost 1.5 ºC above the pre-industrial level, it is obvious that the temperature extremes are likely to continue to increase more than the global average and since the precipitation is decreasing, droughts will be more frequent and intense.

In this work, the spatial and temporal variability of four combined extreme climate indices over the Mediterranean region is investigated under the aspect of the upcoming climate change. More specifically, these combined extremes indices concern Cold/Dry (CD), Cold/Wet (CW), Warm/Dry (WD) and Warm/Wet (WW) days and they are defined by the exceedances of the joint modes of air temperature and precipitation using the 25^th and 75^th percentile levels (European Climate Assessment &Dataset, www.ecad.eu).

The data used for the calculations of the indices concern daily mean temperature and precipitation datasets from an ensemble of 8 regional climate models (RCMs) simulations for the European domain (EURO-CORDEX) with a spatial resolution of 0.11 degree (EUR-11, ~12.5km).  All the calculations and the visualizations of the maps have been conducted in R project.

These extreme indices were calculated seasonally and annually for the periods 2041-2060 (near future) and 2081-2100 (far future), with reference period 1981-2005 for the percentiles, under the RCP2.6, RCP4.5 and RCP8.5 emission scenarios. In addition, seasonal and annual means and trends were estimated for each index for the near future and far future, under all the aforementioned emission scenarios. The findings revealed an increased frequency of WD days in almost all the Mediterranean region and high values of CD days in many areas, against few WW and CW days.

How to cite: Polychroni, I., Hatzaki, M., and Nastos, P.: Variability of combined extreme climate indices over the Mediterranean region under Different Emission Scenarios., EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-505, https://doi.org/10.5194/ems2024-505, 2024.

There is a growing need to understand why the Euro-Mediterranean region and, especially Catalonia, are hotspot regions for both warming as well as drying signals in climate simulations and projections, particularly in summer. Local decision makers call for specific climate information requirements, highlighting the difficulty in having a large range of data sources –observations, global and regional projections, sensitivity and attribution experiments– which lead to discrepancies and analogies regarding the conclusions extracted from different climate data sources. 

In this context, CLIMCAT is a joint project between the Barcelona Supercomputing Center and the Meteorological Service of Catalonia in which a variety of data-storing, evaluation and visualisation tools are employed to provide user-centred climate indices and filtered future projections. For the latter, a process-based evaluation framework based on atmospheric circulation patterns (CPs) is designed, focusing on capturing the synoptic configurations that dominate the Euro-Mediterranean region and their impacts in Catalonia. The hypothesis behind this research is that better-performing GCMs may present more plausible future simulations in a global warming scenario.

CPs are defined using daily mean sea-level pressure (SLP) by means of an Empirical Orthogonal Function (EOF) data reduction combined with Ward's hierarchical clustering. The ECMWF ERA5 reanalysis is considered as reference during 1950-2022 to evaluate a set of 24 global climate models (GCMs) from the Coupled Model Intercomparison Project version 6 (CMIP6). The link between CPs and surface variables –precipitation, maximum and minimum temperatures– is analysed. Model performance is quantified through multiple spatial and temporal metrics, allowing the ranking of the best-performing GCMs. 

It is found that most of the GCMs are able to capture the annual cycle of the CPs frequency in their historical runs, with a dominant summer CP enhancing warm and dry conditions. However, the correct timing of this pattern and the transitional CPs (autumn and spring) are often misrepresented. The analysis of the surface patterns discriminated by CPs presents an overall good model performance, better for the temperatures than rainfall, particularly in the transition seasons, for which the GCMs spread in their skill score increases. 

Finally, when combining spatial and temporal skill metrics, we are able to identify the best-performing GCMs over the Euro-Mediterranean region, allowing a filtering of the large set of CMIP6 projections in different future scenarios. This is a flexible workflow that can be easily modified based on user needs, such as emphasising model capabilities in specific variables and/or atmospheric structures, depending on the regional and local needs to reduce model uncertainty. The approach is designed to support the provision of useful and robust climate information that can benefit policy making at a regional scale.

How to cite: Olmo, M., Cos, P., Altava-Ortiz, V., Barrera-Escoda, A., Campos, D., Loosveldt-Tomas, S., Bretonniere, P.-A., Prohom-Duran, M., Cunillera, J., Muñoz, Á., Doblas-Reyes, F., and Soret, A.: CLIMCAT: Plan for Comprehensive Climate Change Information for Catalonia. Process-based filtering of CMIP6 GCMs projections in the Euro-Mediterranean. , EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-422, https://doi.org/10.5194/ems2024-422, 2024.

Relatively short instrumental streamflow records in the European Alps limit our understanding of the long-term variability of streamflow, which could greatly impact freshwater resources management. To improve the accuracy of future scenarios for rare extreme events that recently impacted severely important water resource systems and communities at the global level, a better understanding of past climatological and hydrological information is essential. Tree-ring-based proxy data have proven to be a viable opportunity for reconstructing streamflow in different regions. Here, the station-based streamflow of six rivers originating from the European Alps are reconstructed dating back to the year 1100 by using a climate-informed framework. Additionally, we use paleo simulations and future projections from state-of-the-art CMIP6 and PMIP4 climate models to study past and future streamflow changes, including the characteristics of rare extreme events like multi-year droughts and floods. By integrating proxy-based reconstructions, climate model simulations and projections, and observations, the changes in streamflow and rare extreme events in the European Alps are put into a millennial perspective covering the past nine centuries and one century into the future. Our findings reveal that the observed worst annual streamflow deficit events are among the most severe in the past 900 years. In addition, climate models project a coherent decrease in streamflow for all the basins, which indicates an unprecedented drought condition in the future. Our framework offers a unique opportunity to assess the risk of extreme events for rivers in the European Alps, thus playing a crucial role in developing robust water management strategies for climate change adaptation.

How to cite: Guo, R., Nguyen, H., Galelli, S., Ceola, S., and Montanari, A.: Streamflow changes in the European Alps indicate increasing drought risk from past to future, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-615, https://doi.org/10.5194/ems2024-615, 2024.

The Adriatic region is one of the rainiest areas in Europe, particularly its coastal mountainous region. This area is often affected by severe weather events like heavy rainfall and flash floods, which pose a severe risk to people and property. Air-sea interactions play a significant role in this region, particularly in the autumn when heavy precipitation events (HPEs) are frequent, and the gradients are high between the sea-surface temperature (SST) and atmospheric temperature.

Atmosphere-only regional climate models (RCMs) are forced by SST as a lower boundary condition, which comes from reanalysis or global models. These models typically have a much lower resolution than the atmosphere-only RCM. On the other hand, regional atmosphere-ocean coupled models (RAOCMs) explicitly resolve air-sea interactions at high resolutions resulting in improved cyclogenesis and precipitation.

Our objective is to assess the impact of ocean-atmosphere coupling on heavy precipitation events that occurred during the first HyMeX Special Observation Period from 5 September to 6 November 2012. We focus on the six intensive observation periods (IOPs) during which heavy precipitation events affected the eastern Adriatic region. Additionally, we assess the performance of the coupled simulations in representing heavy and extreme precipitation at climatological scales.

To achieve this, we use the evaluation atmosphere-only RCMs and RAOCMs simulations from the Med-CORDEX framework. As a reference dataset, we use the precipitation analysis system MESCAN-SURFEX, available at 5.5 km resolution every 6 h, and the rain gauge data from the local observational networks. The main verification method for the HPEs is the quality object-based measure SAL which takes into account the structure (S), the amplitude (A), and the location (L) of the precipitation field. For the climatological scale, we focus on a range of heavy and extreme precipitation indices.

How to cite: Ivusic, S., Güttler, I., and Horvath, K.: The impact of ocean–atmosphere coupling on heavy precipitation events over eastern Adratic and Dinaric Alps, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-713, https://doi.org/10.5194/ems2024-713, 2024.

Abstract.

Background Context - Energy security remains a crucial barrier to achieving sustainable development in Jordan, particularly given the substantial energy demands of the residential sector. In this context, this study will focus on this issue by focusing on low-income housing, considering that it accounts for a substantial portion of the total housing demand in the nation at 44% and experiences high energy consumption due to inadequate environmental design [1], [2]. Low-income households continue to experience persistently high energy consumption rates, indicating significant challenges in improving buildings' energy efficiency due to insufficient knowledge, understanding, and evidence [3]. 

Purpose - This study will investigate the energy performance of low-income designs and their energy consumption pattern in the country's four primary climate zones, namely semi-arid Mediterranean, hot Sahara Mediterranean, warm Sahara Mediterranean, and cool arid Mediterranean.

Case Study – This study will focus on two predominant public low-income typologies, Type-I and Type-M, constructed by the Housing and Urban Development Corporation (HUDC). These typologies are applied throughout the whole country without consideration for their climatic contexts [4], leading to high heating and cooling demand.

Methodology - Using the ClimateStudio plug-in that integrates the EnergyPlus simulation algorithm in the Rhino-Grasshopper software as a primary simulation tool followed by a comparative analysis, allows for a comprehensive understanding of how the two low-income perform under the various climatic conditions present in the country.

Findings - The findings of this study will identify whether these current designs are more appropriate for the different climate zones of Jordan. This study is anticipated to provide evidence-based recommendations for the type of potential energy efficiency improvements that can be targeted at each climatic zone. In addition, it will be intended to guide the designers and decision-makers in promoting and developing energy-conscious housing solutions in low-income settings that align with each climatic zone, thereby mitigating the effect of the energy crisis on the national economy and enhancing sustainability.

Keywords: Building Performance, Energy-Efficiency, Low-Income Housing, Climate Zones.

References

[1]      M. Al-Homoud, S. Al-Oun, and A. M. Al-Hindawi, ‘The low-income housing market in Jordan’, International Journal of Housing Markets and Analysis, vol. 2, no. 3, pp. 233–252, Aug. 2009, doi: 10.1108/17538270910977536.

[2]      H. H. Ali and S. N. Alzu’bi, ‘Design optimization of sustainable affordable housing model in hot-arid climate-case of Jordan’, International Journal of Housing Markets and Analysis, vol. 10, no. 5, pp. 607–627, Nov. 2017, doi: 10.1108/IJHMA-01-2017-0009.

[3]      F. S. Hafez et al., ‘Energy Efficiency in Sustainable Buildings: A Systematic Review with Taxonomy, Challenges, Motivations, Methodological Aspects, Recommendations, and Pathways for Future Research’, Energy Strategy Reviews, vol. 45, p. 101013, Jan. 2023, doi: 10.1016/j.esr.2022.101013.

[4]      A. A. Al Haija, ‘Environmental and Social Issues in Jordanian Low-Income Housing Design’, Open House International, vol. 36, no. 4, pp. 111–120, Dec. 2011, doi: 10.1108/OHI-04-2011-B0010.

How to cite: Maaith, N. and Sharmin, T.: Investigate the Impact of Climatic Conditions on the Building Energy Performance of Low-income Housing in Jordan, EMS Annual Meeting 2024, Barcelona, Spain, 1–6 Sep 2024, EMS2024-1070, https://doi.org/10.5194/ems2024-1070, 2024.