The activities of the Asian summer monsoon are modulated by large-scale land-sea thermal contrast and the thermal forcing of the Iranian Plateau-Tibetan Plateau. The vast quantity of latent heat released by Asian monsoon precipitation forms a kind of feedback to the atmospheric circulation. This feedback is so complicated that it is very important to reveal the physical processes involved. Doing so will help us to understand the formation and variation of the climate pattern, as well as improve the accuracy of weather predictions and climate forecasts. The main subtropical climate system existing in the upper troposphere in boreal summer is characterized by the huge South Asia High (SAH) and the Upper-Tropospheric Temperature Maximum (UTTM). This paper introduces the development of the theory of the temperature-vertical heating gradient (T-Q_Z), and uses it to explain the formation mechanism of the SAH and UTTM. It is proven that the latent heating over the subtropical eastern Eurasian continent, the sensible heating over the central continent, and the longwave cooling in the upper troposphere are the causes of the development of the SAH and UTTM in the upper troposphere in South Asia. This paper also documents the limitation of the Gill model in studying upper-troposphere dynamics and provides a relevant solution.