Thermal controls on the Asian summer monsoon

Area of Science:

• Climatology
• Atmospheric Science
• Meteorology

Background:

• The Asian summer monsoon impacts over 60% of the global population.
• Understanding monsoon dynamics is crucial for climate change adaptation.
• Existing theories on monsoon drivers lack a unified paradigm.

Purpose of the Study:

• To identify the dominant factors controlling the Asian summer monsoon system.
• To differentiate the specific thermal forcing mechanisms for regional monsoons.

Main Methods:

• Analysis of observational data.
• Conducting numerical experiments.

Main Results:

• Thermal forcing, not orographic forcing, is the main driver of Asian monsoon systems.
• South Asian monsoon (south of 20°N) is controlled by land-sea thermal contrast.
• Northern South Asian monsoon is driven by Iranian Plateau thermal forcing.
• East Asian and eastern South Asian monsoons are influenced by Tibetan Plateau thermal forcing.

Conclusions:

• Thermal forcing is the essential mechanism for Asian summer monsoon generation and strength.
• Specific regional monsoons are uniquely controlled by distinct thermal forcings.