The seasons’ length in 21st century CMIP5 projections over the eastern Mediterranean

Abstract

The eastern Mediterranean (EM) is expected to be influenced by climate changes that will significantly affect ecosystems, human health and socio‐economic aspects. One aspect of climate change in this vulnerable area is the length of the seasons, especially that of the rainy winter season against the warm and dry summer. Here, the synoptic seasons’ definition of Alpert, Osetinsky, Ziv, and Shafir (2004a) was applied to an ensemble of eight Coupled Model Inter‐Comparison Project phase 5 (CMIP5) models, under RCP8.5 and RCP4.5 scenarios, to predict the changes in the lengths of EM seasons during the 21st century. It is shown that the ensemble adequately represents the annual cycle of the main synoptic systems over the EM. The analysis further suggests that at the end of the 21st century, the duration of the synoptic summer, characterized by the occurrence of the Persian Trough, is expected to be lengthened by 49%, while the synoptic winter, characterized by the occurrence of the Cyprus Low, is expected to be shortened by 56% under the RCP8.5 scenario. This may lead to substantial changes in the hydrological regime and water resources, reduce the potential of dry farming, increase the risk of fires and air pollution and change the timing of seasonal health hazards.

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

“…Due to the absence of 12UTC data at the 1,000‐hPa level in CMIP5 models, we use U and V wind components and temperature from the 850‐hPa level, as well as sea level pressure (SLP). The compatibility between the 1,000 and the 850‐hPa levels, and that of the 12UTC with daily classifications was examined by Hochman et al (, c) and Berkovic (), respectively, and was shown to fit well. Nevertheless, the ability of the two downscaling methods used, that is, the modified algorithm for the synoptic classification (the “weather regimes”) and the “analogues” to downscale observed seasonal precipitation is evaluated here for both the NCEP/NCAR reanalysis and the CMIP5 models.…”

“…Modeled data for six models participating in the fifth phase of the Coupled Model Inter‐Comparison Project (CMIP5; Taylor et al, ) were retrieved from the World Data Center for Climate (WDCC‐DKRZ, http://cera-www.dkrz.de/WDCC/ui/Index.jsp) data portal. These models were previously utilized in Hochman et al (, c, and 2019) (list of models see Table ) and their ability to simulate annual and extreme precipitation indices over the eastern Mediterranean was previously presented by Samuels et al (). 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 (, c, and 2019).…”

“…This classification successfully describes the local weather conditions as well as various environmental phenomenon as dust, floods and air pollution (e.g., Dayan et al, 2012;Saaroni et al, 2010aSaaroni et al, , 2010bSaaroni et al, , 2010c. This classification has been successfully used to define the seasons over the eastern Mediterranean (Alpert et al, 2004b), to project seasons' length changes for the 21st century (Hochman et al, 2018b) and to diagnose future changes in the local atmospheric dynamics of the synoptic systems (Hochman et al, 2018c(Hochman et al, , 2019, as well as many other applications. Hochman et al (2018c) have projected a~30% decrease in the number of Cyprus Lows by the end of the 21st century under the RCP8.5 scenario.…”

High thermal plasticity and vulnerability in extreme environments at the warm distributional edge: the case of a tidepool shrimp

“…A limited global analysis across realms suggested that animals from more 15 stable environments have greater capacity for acclimation compared to unstable ones, 16 but pointed out that generality of such patterns is limited because much of the world is 17 undersampled (Seebacher et al, 2015). 18 On the rapidly warming Israeli coast, which is the southeastern edge of distribution of 19 most Mediterranean and Atlanto-Mediterranean species, and where the water is 20 naturally hottest in the basin, tidepool ecology has not been studied before, but it is 21 assumed that the pools can get extremely hot when disconnected from the sea. This 22 study focuses on the small rockpool shrimp Palaemon elegans (Rathke 1837).…”

“…Seasonal acclimatization of oxygen consumption rates has been previously documented valuable feature that may lead to adaptive shifts in thermal breadth, thermal optima and 20 higher fitness (Somero, 2002). Acclimatization is a known mechanism that enables the 21 organism to cope with the changing environmental temperature that occurs seasonally.…”