A new study led by Dr. HUANG Gang from the Institute of Atmospheric Physics of the Chinese Academy of Sciences has unveiled how the South Asian High (SAH) responds to shifting carbon dioxide (CO2) levels.
The SAH, a significant anticyclone spanning the upper troposphere and lower stratosphere over the Asian continent, plays a pivotal role in climate dynamics. Driven by the South Asian summer monsoon and the heating of the Tibetan Plateau, the SAH influences various climate responses with far-reaching implications.
This study investigated the effects of different atmospheric CO2 concentration pathways on the SAH, as well as its underlying mechanisms.
The South Asian High, a massive anticyclone over the southern part of the Asian continent, plays a vital role in influencing underlying climate and mass transport. (Image by QU Xia)
"At an altitude of 100 hPa, we observed that the SAH strengthens and shifts equatorward as CO2 concentrations increase. Even when CO2 concentrations stabilize, the SAH continues to migrate southward, with little change in intensity," said Prof. HUANG, corresponding author of the study.
After examining the outcomes of the linear baroclinic model, they determined that as CO2 concentrations rise, diabatic heating plays a role in strengthening the SAH. Additionally, both diabatic heating and alterations in stratification contribute to the southward movement of the SAH. When CO2 concentrations stabilize, diabatic heating and alterations in stratification contribute to the equatorward displacement of the SAH.
However, it's worth noting that two components of diabatic heating, namely latent heating and residual heating, offset each other, resulting in minimal changes in SAH intensity.
