Evaluation and projection of extreme precipitation indices in the Eastern Mediterranean based on CMIP5 multi‐model ensemble

Abstract

An evaluation of 23 models, participating in the Coupled Model Inter‐comparison Project phase 5 (CMIP5), in representing extreme precipitation indices (EPI), over the Eastern Mediterranean (EM) and the Fertile Crescent (FC), was performed. The models ensemble was then used to predict the EPIs evolution in the 21st century under (Representative Concentration Pathway, RCP) RCP4.5 and RCP8.5 scenarios. Models' performance was determined with respect to gridded precipitation observations from the APHRODITE project. The ensemble mean was found to perform relatively well in capturing the EM steep precipitation gradient, the FC structure and the EPI trends in the observations period (1970–2000). Over the EM, CMIP5 models agree on a future decrease in the following three EPIs; total precipitation (TP), consecutive wet days, and number of wet days by the values of 20–35%, 10–20%, and 20–35%, respectively. In the FC, extremely wet days (P95) are expected to increase by approximately 25%, except for the south eastern coasts of the Mediterranean Sea, which show significant decreases in P95, particularly for RCP8.5 and at the end of the 21st century. Hence, while TP is expected to decrease, extreme precipitation is expected to increase, at least for the north‐eastern part of the FC. This will significantly influence agriculture and floods' potential in a region already suffering from political unrest. The changes in EPIs are related to changes in the synoptic patterns over the EM, especially the predicted changes in cyclones frequency and intensity in the 21st century, due to changes in storm tracks governed by the phase of the North Atlantic Oscillation and the expected expansion of the Hadley Cell towards the poles in a warmer climate.

High‐resolution projection of climate change and extremity over Israel using COSMO‐CLM

“…A projected tendency towards drier conditions is confirmed by the simulation for the Mediterranean climate and semi-arid climate of Israel, in agreement with low-resolution projections (Samuels et al, 2017). Note that the absolute precipitation amounts are very different between the northern Mediterranean climate and the southern arid climate; the region showing projected reductions in precipitation is larger than the region showing increases.…”

“…Accordingly, climate projections over the 21st century have been conducted adopting the same spatial resolutions. Initial and boundary conditions were derived by the global climate model CMCC-CM (Scoccimarro et al, 2011), which was found to represent EPI in the EM relatively well (Samuels et al, 2017). Initial and boundary conditions were derived by the global climate model CMCC-CM (Scoccimarro et al, 2011), which was found to represent EPI in the EM relatively well (Samuels et al, 2017).…”

“…The future projections are performed under the IPCC representative concentration pathway 4.5 (RCP4.5) scenario (Moss et al, 2010), which assumes that greenhouse gases will increase and peak around 2040, and then will start to decline. Initial and boundary conditions were derived by the global climate model CMCC-CM (Scoccimarro et al, 2011), which was found to represent EPI in the EM relatively well (Samuels et al, 2017).…”

“…To gain a uniform perspective on changes in weather and climate extremes, an internationally coordinated core set of 27 indices of temperature and precipitation extremes was defined by the Expert Team on Climate Change Detection and Indices (ETCCDI; Klein-Tank et al, 2009;Zhang et al, 2011). These extreme indices have multiple applications in climate research due to their robustness and have been widely used for analyzing past and future trends in extremes (e.g., Samuels et al, 2011;Smiatek et al, 2011;Soares et al, 2012;Dominguez et al, 2013;Turco et al, 2013;Zollo et al, 2016;Samuels et al, 2017;Zittis, 2017). Samuels et al (2017) have evaluated the ability of 23 models, participating in the Coupled Model Intercomparison Project phase 5 (CMIP5), to predict extreme precipitation indices (EPI) in the 21st century over the EM.…”

Weather regimes and analogues downscaling of seasonal precipitation for the 21st century: A case study over Israel

“…dkrz.de/WDCC/ui/Index.jsp) data portal. These models were previously utilized in Hochman et al (2018b, c, and2019) (list of models see Table 1) and their ability to simulate annual and extreme precipitation indices over the eastern Mediterranean was previously presented by Samuels et al (2017). Furthermore, these models' ability to simulate the annual cycle of the prevailing eastern Mediterranean synoptic systems, their frequencies, and dynamics for the historical period were presented in Hochman et al (2018b, c, and2019).…”