Present and future land surface and wet bulb temperatures in the Arabian Peninsula

S Safieddine,E A B Eltahir,L Clarisse,S Whitburn,C Clerbaux

doi:10.1088/1748-9326/ac507c

Abstract

The Arabian Peninsula exhibits extreme hot summers and has one of the world’s largest population growths. We use satellite observations and reanalysis as well as climate model projections to analyze morning and evening land surface temperatures (LSTs), to refer to processes at the surface, and wet bulb temperatures (WBTs) to measure human heat stress. We focus on three regions: the Persian Gulf and Gulf of Oman, the inland capital of Saudi Arabia, Riyadh and the irrigated agricultural region in Al-Jouf, Saudi Arabia. This study shows that the time of day is important when studying LST and WBT, with current and future WBT higher in the early summer evenings. It also shows that the effect of humidity brought from waterbodies or through irrigation can significantly increase heat stress. Over the coasts of the Peninsula, humidity decreases LST but increases heat stress via WBT values higher than 25 °C in the evening. Riyadh, located in the heart of the Peninsula has lower WBT of 15 °C–17.5 °C and LST reaching 42.5 °C. Irrigation in the Al-Jouf province decreases LST by up to 10° with respect to its surroundings, while it increases WBT by up to 2.5°. Climate projections over the Arabian Peninsula suggest that global efforts will determine the survivability in this region. The projected increase in LST and WBT are +6 °C and +4 °C, respectively, in the Persian Gulf and Riyadh by the end of the century, posing significant risks on human survivability in the Peninsula unless strict climate mitigation takes place.

Highlights

Most land regions are experiencing greater warming than the global average temperature increase[1], and the projections of future temperatures have large regional and local uncertainties since models fail in the representation of local land processes[2]
We present here two variables that can help us understand this complex relationship in a region with extreme heat in summer, the Arabian Peninsula: the land surface temperature (LST) and the wet bulb temperature (WBT)
The Arabia Peninsula is well-targeted since the cloud cover over this region during summer is negligible, giving IASI frequent access to the surface in order to derive clearsky LST

Summary

Introduction

Most land regions are experiencing greater warming than the global average temperature increase[1], and the projections of future temperatures have large regional and local uncertainties since models fail in the representation of local land processes[2]. Differences between LST and atmospheric near surface temperature can be large under cloud-free, low wind speed conditions since land heats much faster than air, and smaller under cloudy conditions or when solar insolation is low[5]. It is an important factor for studying the Earth’s energy balance, convection at the surface, monitoring droughts, land use, and surface urban heat islands (SUHI)[6,7]. LST has been identified as one of the most significant factors that can influence

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