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M.M. Messmer

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3 records found

Historical validation and future projections under different shared socioeconomic pathways

Journal article (2026) - Martina Messmer, Santos J. González-Rojí, Mo Aung Nay Chi, Sonia Leonard
Myanmar is one of the most vulnerable countries to climate change, and its complex geography together with heterogeneous climate and precipitation patterns present major challenges for producing reliable climate change projections. In light of these challenges, high-resolution regional climate models are essential for improving our understanding of climate change and to provide a knowledge base for adaptation strategies. We employed the Weather Research and Forecasting (WRF) model to simulate the present climate (1981–2010), a mid of century (2031–2060) and an end of century (2071–2100) climate for the SSP2-4.5 and SSP5-8.5 scenarios. We tested out different domain settings and show that large domains are needed to accurately model the climate and, particularly, precipitation in Myanmar. The past climate is validated against station data and satellite based products, and the model demonstrates good skill in representing the climate over Myanmar, with the exception of a dry bias in the southern Ayeyarwady Delta. Generally, the model underestimates precipitation at the end of the rainy season in October, which is related to a mismatch in the atmospheric circulation, moisture availability, and therefore, moisture transport into Myanmar. The climate projections show distinct increases in 2m-temperature, with warming of 0.9 to 2.7 °C for the mid-century in an SSP2-4.5 to end of the century under the SSP5-8.5. Our simulations project that in April the temperature in the Dry Zone in the centre of the country increases disproportionally with a warming of up to 3.6 °C for the SSP5-8.5 end of century simulation, while for all other scenarios the strongest increase is found in May. Changes in precipitation show a non-significant wetting in the Dry Zone and a significant drying in the Shan Hills and the Tanintharyi Region for the two periods in the SSP2-4.5 and the mid-century simulation under SSP5-8.5 scenario. For the end of century simulation under the SSP5-8.5 pathway a general wetting of the north western part including the Dry Zone in the range of 40 to 60% is projected. Even if the annual sum shows an increase in precipitation, this is not true for all the months. Especially, January, July, August and November are months which are projected to have less precipitation in all future scenarios compared to present climate. ...
Journal article (2025) - Onno Doensen, Martina Messmer, Woon Mi Kim, Christoph C. Raible
Extratropical cyclones are important meteorological phenomena in the Mediterranean and are essential for local water supplies, yet they also pose significant hazards for the region as a result of extreme precipitation or wind events. Although they have been extensively studied using global and regional climate models, their spatial and temporal variability in the Late Holocene is poorly understood. Here, we study a 3350-year climatological simulation that allows us to characterize Mediterranean cyclones better and provides a baseline for more accurately assessing the long-Term effects of future climate change on Mediterranean cyclones. To analyse Mediterranean cyclone characteristics, we use a seamless transient simulation from 1500 BCE to 1850 CE produced by the Community Earth System Model (CESM) with a 6-hourly temporal and 1.9°×2.5° horizontal resolutions. We found that Mediterranean cyclones exhibit pronounced multi-decadal variability in the order of 5 % throughout the entire Late Holocene with respect to several cyclone-related properties. For the cyclone frequency, a weak statistical relationship is identified with the East Atlantic (EA), East Atlantic/Western Russia (EAWR), and Scandinavian (SCAN) modes of circulation. Composite analyses of the most extreme cyclones with respect to wind speed and precipitation indicate that cyclones in the central Mediterranean have the potential to grow more intense over their entire lifetime than cyclones in the eastern Mediterranean. This is especially true for extreme wind speed cyclones, implying that people in the central Mediterranean are potentially more exposed to hazards caused by extreme cyclones. ...
Journal article (2024) - Martina Messmer, Sandra Eckert, Amor Torre-Marin Rando, Mark Snethlage, Santos J. González-Rojí, Kaspar Hurni, Urs Beyerle, Andreas Hemp, Staline Kibet, Thomas F. Stocker
Grassland landscapes are important ecosystems in East Africa, providing habitat and grazing grounds for wildlife and livestock and supporting pastoralism, an essential part of the agricultural sector. Since future grassland availability directly affects the future mobility needs of pastoralists and wildlife, we aim to model changes in the distribution of key grassland species under climate change. Here we combine a global and regional climate model with a machine learning-based species distribution model to understand the impact of regional climate change on different key grass species. The application of a dynamical downscaling step allows us to capture the fine-scale effects of the region’s complex climate, its variability and future changes. We show that the co-occurrence of the analysed grass species is reduced in large parts of eastern Africa, and particularly in the Turkana region, under the high-emission RCP8.5 scenario for the last 30 years of the 21st century. Our results suggest that future climate change will alter the natural resource base, with potentially negative impacts on pastoralism and wildlife in East Africa. ...