Stratospheric temperature features over Saudi Arabia and their relations with Atlantic SSTs and surface temperatures in winter

Abstract

Stratospheric weather and climate conditions are closely linked to tropospheric conditions. Stratospheric temperature is an important climatic factor regionally and globally. This paper studies temperature trends in the lower stratosphere at 50 hPa (T50), the mid-stratosphere at 30 hPa (T30) and the upper stratosphere at 10 hPa (T10) throughout winter and their impacts on Atlantic Ocean sea surface temperature and Saudi Arabian surface air temperature, SAT, in the period 1950-2019. The T50 trend over Saudi Arabia showed warming in 1959-1992 (first period) and cooling in 1993-2019 (second period). The T30 trend depicted progressive cooling throughout the overall period. The T10 trend revealed cooling overall with significant warming in the first period. Stratospheric temperatures influence climate change. The standard deviation outcomes showed relatively high inconsistencies in stratospheric-temperature time series. Analysis of the nonlinear trend in stratospheric temperature shows significant cooling for T30 and T10. A strong negative relationship exists between T10 and SST over the Atlantic Ocean. T50 indicates a strong negative relationship with the Atlantic multi-decadal oscillation (AMO) and the tropical southern Atlantic (TSA) indices. T30 relates more to the TSA and the northern tropical Atlantic (NTA) indices than T10 and T50. The lead-lag cross-correlation suggests that the SSTs of the Atlantic Ocean are linked to stratospheric temperatures at a zero lag for T10 and after three winter seasons for T50 and T30, with the exception of the TSA, which is linked at a zero lag. SSTs affect stratospheric temperatures as follows: 1) greenhouse gases from SSTs increase tropospheric temperatures while cooling the stratosphere, and 2) SSTs impact the vertical propagation of tropospheric waves entering the stratosphere. SAT/stratospheric temperature coupling occurs in winter, especially in the lower to mid-stratosphere layers.