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Reduced Rainfall in Future Heavy Precipitation Events Related to Contracted Rain Area Despite Increased Rain Rate
  • +5
  • Moshe Armon,
  • Francesco Marra,
  • Yehouda Enzel,
  • Dorita Rostkier-Edelstein,
  • Chaim I Garfinkel,
  • Ori Adam,
  • Uri Dayan,
  • Efrat Morin
Moshe Armon
Hebrew University of Jerusalem, Hebrew University of Jerusalem

Corresponding Author:[email protected]

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Francesco Marra
Institute of Atmospheric Sciences and Climate, National Research Council, Institute of Atmospheric Sciences and Climate, National Research Council
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Yehouda Enzel
Hebrew University of Jerusalem, Hebrew University of Jerusalem
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Dorita Rostkier-Edelstein
Department of Environmental Physics, Environmental Sciences Division, IIBR, Department of Environmental Physics, Environmental Sciences Division, IIBR
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Chaim I Garfinkel
Hebrew University of Jerusalem, Hebrew University of Jerusalem
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Ori Adam
Hebrew University, Hebrew University
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Uri Dayan
Department of Geography, Hebrew University of Jerusalem, Department of Geography, Hebrew University of Jerusalem
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Efrat Morin
Institute of Earth Sciences, The Hebrew University of Jerusalem, Institute of Earth Sciences, The Hebrew University of Jerusalem
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Abstract

Heavy precipitation events (HPEs) can lead to deadly and costly natural disasters and are critical to the hydrological budget in regions where rainfall variability is high and water resources depend on individual storms. Thus, reliable projections of such events in the future are needed. To provide high-resolution projections under the RCP8.5 scenario for HPEs at the end of the 21st century and to understand the changes in sub-hourly to daily rainfall patterns, weather research and forecasting (WRF) model simulations of 41 historic HPEs in the eastern Mediterranean are compared with “pseudo global warming” simulations of the same events. This paper presents the changes in rainfall patterns in future storms, decomposed into storms’ mean conditional rain rate, duration, and area. A major decrease in rainfall accumulation (-30% averaged across events) is found throughout future HPEs. This decrease results from a substantial reduction of the rain area of storms (-40%) and occurs despite an increase in the mean conditional rain intensity (+15%). The duration of the HPEs decreases (-9%) in future simulations. Regionally maximal 10-min rain rates increase (+22%), whereas over most of the region, long-duration rain rates decrease. The consistency of results across events, driven by varying synoptic conditions, suggests that these changes have low sensitivity to the specific large-scale flow during the events. Future HPEs in the eastern Mediterranean will therefore likely be drier and more spatiotemporally concentrated, with substantial implications on hydrological outcomes of storms.
Jan 2022Published in Earth's Future volume 10 issue 1. 10.1029/2021EF002397