Midlatitude circulations linked to seasonal extreme precipitation and extreme temperature events in the Arabian Peninsula

In this study, the European Center for Medium-Range Weather Forecasts Reanalysis version 5 daily datasets are analyzed to investigate the association between atmospheric Rossby waves and climate variability over the Arabian Peninsula (AP) from 1981 to 2022. The potential impacts of Rossby waves on regional extreme precipitation and extreme temperature events during different seasons, namely extended winter (November–April), transition months (May–June), and extended summer (July–October) are investigated. We find that during extended winter, amplified Rossby waves with wave numbers 5–8 in the subtropical westerly jet stream, originating from the northern Atlantic and Mediterranean Sea, lead to stronger-than-normal cyclonic conditions, and thereby, an anomalous increase in the number of extreme precipitation days in the northern AP. When the waves number 1–4 weaken, they cause anomalous anticyclonic conditions and result in extreme temperatures across the AP. Moreover, Rossby wave incursions cause extreme precipitation and extreme temperatures in the southern AP, which are considerably affected by tropical processes. Days with extreme temperatures during the transition months are associated with eddy Rossby waves with wave numbers 4–8 that propagate from higher latitudes through the Mediterranean region across the North AP. However, the frequency of extreme precipitation days over the AP during these months is not affected by the Rossby waves. The amplitudes of eddy Rossby waves over the AP are weak from July to October. Consequently, their influence on local extreme precipitation and extreme temperature is insignificant. 

Arabian Peninsula Climate Variability Precipitation and temperature extreme Rossby waves Subtropical westerly jet