Novel Approaches for Downscaling of 21st Century Precipitation Extremes –Focus over the Mediterranean & Mid-East

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 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 et al. (2004) was applied to an ensemble of eight 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. Global and regional multi-model evaluation indicates strong warming and drying of the Mediterranean region (Hochman et al.,2018).

Precipitation predictions: Japanese and RCM models both show increased interannual variability and probability for increases of multi-year droughts.

Additional information from ensemble of climate models is shown to improve our ability to answer questions such as “what is the probability that there will be a multi-year drought or severe heat wave in the coming decades?” and help inform our policy and adaptive response. I will highlight the benefit of using APHRODITE rain data over the Mid-East for evaluation of CMIP5 ensembles with focus on extreme indicators (Hochman et al. 2017, 2018, Samuels et al., 2017).Different ensemble approaches are employed to project changes in some significant climate rain indicators for the 21^st century. I will present new method tested over the E. Mediterranean that demonstrates the usefulness of a predictability index for extreme weather (Hochman et al., 2019).

References:

2004. Alpert, I. Osetinsky, B. Ziv and H. Shafir, "A new seasons definition based on the classified daily synoptic systems: An example for the Eastern Mediterranean", International Journal of Climatology, 24, 1013-1021, 2004.
2005. Hochman, T. Harpaz, H. Saaronia and P. Alpert, "Synoptic classification in 21st century CMIP5 predictions over the Eastern Mediterranean with focus on cyclones", Int. J. Climatol. 38, 1476-1483, 2018, DOI: 10.1002/joc.5260
2006. Hochman, T. Harpaz, H. Saaroni and P. Alpert, "The seasons' length in 21st century CMIP5 projections over the eastern Mediterranean", Int. J. Climatol., 38(6), 2627-2637, 2018, DOI: 10.1002/joc.5448
2007. Hochman, E. Bucchignani, G. Gershtein, S. O. Krichak, P. Alpert, Y. Levi, Y. Yosef, Y. Carmona, J. Breitgand, P. Mercoglianoc and A. L. Zolloc, " Evaluation of regional COSMO-CLM climate simulations over the Eastern Mediterranean for the period 1979–2011", Int. J. Climatol, 38, 1161-1176,. 2018, DOI: 10.1002/joc.5232.
2008. Hochman, T. Harpaz, H. Saaroni and P. Alpert, "The seasons' length in 21st century CMIP5 projections over the eastern Mediterranean", Int. J. Climatol., 38(6), 2627-2637, 2018, DOI: 10.1002/joc.5448
2009. Hochman, P. Alpert, T. Harpaz, H. Saaroni, G. Messori, ”A new dynamical
      systems perspective on atmospheric predictability: eastern Mediterranean weather
      regimes as a case study", Science Advances, DOI:10.1125/sciadv.aau0936, 2019.
2010. Samuels, A. Hochman (equally contributed), A. Baharad, A. Givati, Y. Levi, Y. Yosef, H. Saaroni, B. Ziv, T. Harpaza and P. Alpert, "Evaluation and projection of extreme precipitation indices in the Eastern Mediterranean based on CMIP5 multi-model ensemble", Int. J. Clim., DOI: 10.1002/joc.5334, 2017.