Extreme High Temperatures in the Indochina Peninsula and Their Association With Enhanced Convection in the Horn of Africa and Arabian Peninsula During Spring 2023

ABSTRACT This study investigates the mechanisms underlying persistent extreme high temperatures over the Indochina Peninsula (ICP) in spring 2023, which occurred following a La Niña winter, contrasting with previous events that typically followed El Niño winters. Analysis reveals that a persistent “heat dome” pattern over the ICP during spring 2023 created favorable conditions for extreme heat. Wave activity flux analysis and linear baroclinic model simulations consistently suggest that the enhanced convection in the Horn of Africa and Arabian Peninsula play a significant contributing role in the heat dome via Rossby waves propagation. Specifically, the energy dispersion of Rossby waves contributes to the direct formation of an anomalous anticyclone in the upper troposphere over the ICP. Concurrently, the westerly flow on the southern flank of the anomalous cyclone over South Asia — part of the same wave train — facilitates strong upper‐level convergence and subsidence over the ICP, promoting the establishment and maintenance of the heat dome.