Temperature Changes over the CORDEX-MENA Domain in the 21^st Century Using CMIP5 Data Downscaled with RegCM4: A Focus on the Arabian Peninsula

Abstract

This paper examined the temperature changes from the COordinated Regional climate Downscaling Experiment (CORDEX) over the Middle East and North Africa (MENA) domain called CORDEX-MENA. The focus is on the Arabian Peninsula in the 21st century, using data from three Coupled Model Intercomparison Project Phase 5 (CMIP5) models downscaled by RegCM4, a regional climate model. The analysis includes surface observations along with RegCM4 simulations and changes in threshold based on extreme temperature at the end of the 21st century relative to the base period (1971–2000). Irrespective of the driving CMIP5 models, the RegCM4 simulations show enhanced future temperature changes for RCP8.5 as compared to RCP4.5. The Arabian Peninsula will warm at a faster rate (0.83°C per decade) as compared to the entire domain (0.79°C per decade) for RCP8.5 during the period 2071–2100. Moreover, the number of hot days (Tmax ≥ 50°C) (cold nights: Tmin ≤ 5°C) will increase (decrease) faster in the Arabian Peninsula as compared to the entire domain. This increase (decrease) of hot days (cold nights) will be more prominent in the far future (2071–2100) as compared to the near future (2021–2050) period. Moreover, the future changes in temperature over the main cities in Saudi Arabia are also projected. The RegCM4-based temperature simulation data from two suitable CMIP5 models are recommended as a useful database for further climate-change-related studies.

Climate Extremes over the Arabian Peninsula Using RegCM4 for Present Conditions Forced by Several CMIP5 Models

“…This large rate of increase in surface temperature over the Peninsula causes many temperature extremes in the region and indicates the need for a disaster management program [5]. In a recent study Almazroui et al [6] presented evidence that during the 21st century, temperature over the Peninsula will warm at a faster rate than over the larger COordinated Regional climate Downscaling Experiment (CORDEX) Middle-East and North Africa (MENA) domain. In addition to this rise in temperature, changes in precipitation were also observed over the Peninsula.…”

“…Some information on climate extremes over the Arabian Peninsula is also available from analysis using IPCC AR4 (CMIP3) and AR5 (CMIP5) multi-models data [18]. However, to the best of our knowledge, details on the analysis of extremes using CMIP5 multi-models downscaled by regional climate model and compared with the observations are not available for the region except for the work of Almazroui [6] who showed that threshold based warm days (Tmax ≥ 50 • C) will increase and cold nights (Tmin ≤ 5 • C) will decrease faster over the Arabian Peninsula than over the wider region. Nevertheless, no climate model simulation is free from uncertainty and that in particular, the simulation of precipitation and temperature on a daily scale is a challenging task.…”

Mid-Century Changes in the Mean and Extreme Climate in the Kingdom of Saudi Arabia and Implications for Water Harvesting and Climate Adaptation

“…We choose ERA-Interim as our driver field because ERA-Interim was, at the time of simulations, one of the best available reanalysis products (e.g., [22,38]). Furthermore, both ERA-Interim and its predecessor ERA-40 have been extensively used in similar downscaling studies focusing on analysis of regional climate change across different regions around the world and as proxy for observations (e.g., [20,26,[37][38][39][40]); most importantly, they have been used in this context over the AP (e.g., [6,11,41]).…”

“…The Kingdom of Saudi Arabia (KSA) has a dry, hot climate with infrequent rainfall (e.g., [1]). Several studies show increasing trends in temperatures in station observations across KSA (e.g., [2][3][4][5]) as well as in gridded observational products (e.g., [6]). For example, Almazroui et al (2014) investigated the trends of extreme temperatures in Saudi Arabia using observations from 27 ground-based stations for 30 years (1981-2010) and found that temperature extremes were higher in magnitude and more frequent for both cold and warm extremes during the most recent decade (1996-2010) of their analysis [4].…”

“…Several studies were performed to assess future climate change in the region using Earth System Model (ESM) projections as well as dynamical downscaling of ESMs using regional climate models (e.g., [6,8,9,11,19]). While these studies were useful to understand and reveal potential changes in climate and the complexities associated with representing the unique spatial features of KSA, the horizontal resolutions of these studies were too coarse to study changes in climate in local scales and to be used in local-scale adaptation studies.…”