Evolution of surface air temperature during the pre-monsoon season over the Indian Peninsula: Dominant monthly patterns and their drivers

https://doi.org/10.1016/j.atmosres.2025.108599
2025-10-29
Atmospheric Research
Sizhuo Chen , Huixin Li , Jiani Zeng , Botao Zhou , Mingkeng Duan
Pre-monsoon season (March–April–May, MAM) constitutes the primary heat season across the Indian Peninsula (0°–40°N, 60°–100°E), marked by frequent occurrences of extreme surface air temperature (SAT) events. These extreme heat conditions not only impact regional climate but may also propagate remotely to East Asia via atmospheric teleconnections. Despite their significance, the monthly evolution of SAT over the Indian Peninsula and its governing mechanisms remain inadequately quantified. This study investigates the monthly variability of pre-monsoon SAT over the Indian Peninsula during the period 1970–2024, emphasizing synergistic roles of internal atmospheric dynamics and sea surface temperature (SST) forcing. Results show that SAT anomalies in March and April exhibit a spatially coherent pattern across the the peninsula, associated with the North Atlantic Oscillation (NAO) and North Pacific Oscillation (NPO), respectively. Notably, April SAT anomalies are further modulated by SST anomalies south of Greenland through wave-mean flow interactions. In contrast, May SAT anomalies display a distinct east–west dipole pattern, characterized by opposing SAT anomalies between northwestern (22°–40°N, 60°–82°E) and eastern (10°–30°N, 82°–100°E) peninsula sectors. The May dipole arises from a “Z-shaped” SST anomaly pattern in the eastern Pacific, which initiates a Rossby wave train. During its propagation across Greenland, this wave train undergoes amplification via air–sea coupling with local SST anomalies, ultimately intensifying downstream impacts on the Indian Peninsula.
关键词
  • Indian Peninsula
  • Pre-monsoon season
  • Surface air temperature
  • Rossby wave train
  • Atmospheric teleconnection