Variations in the Sensible Heating of Tibetan Plateau and Related Effects on Atmospheric Circulation Over South Asia

Abstract

Thermal effects of the Tibetan Plateau (TP) play an important role in the atmospheric circulation over south Asia, which may have complex implications on the development of regional climate. In the study, we utilized 86 station-based observations (1980–2018) to investigate the variations in sensible heating on the plateau surface and their possible impacts on south Asian atmospheric circulation in terms of the Indian Subtropical High. With 10-year records expansion relative to prior studies, our results suggested the significant increasing trend in regional sensible heat (SH) flux from 2001 to 2018 (0.259 W m− 2 a− 1, p < 0.05) contrary to the earlier pronounced decrease (-0.172 W m− 2 a− 1, p < 0.05; 1980–2000) especially in cold season. Most (33) of the 35 stations that decreased in cold-season SH flux before the shift year 2000, did not remain such temporal trend after 2000. Totally, there were respectively 44 and 5 stations showing increasing and decreasing trends in cold-season SH flux from 2001 to 2018, in contrast to the corresponding 6 and 35 stations during the period of 1980–2000. Our results also indicated that the later stronger sensible heating from the TP exhibited statistically close correlation (-0.574~-0.445 o/(W m− 2), p < 0.05) with the Indian Subtropical High, which tended to move southerly and shrink. Our study highlighted the possible weakening effect of the TP’s intensifying sensible heating on the atmospheric circulation over south Asia due to climate warming.