Orographic Controls on Climate and Paleoclimate of Asia: Thermal and Mechanical Roles for the Tibetan Plateau

Abstract

Prevailing opinion assigns the Tibetan Plateau a crucial role in shaping Asian climate, primarily by heating of the atmosphere over Tibet during spring and summer. Accordingly, the growth of the plateau in geologic time should have written a signature on Asian paleoclimate. Recent work on Asian climate, however, challenges some of these views. The high Tibetan Plateau may affect the South Asian monsoon less by heating the overlying atmosphere than by simply acting as an obstacle to southward flow of cool, dry air. The East Asian “monsoon” seems to share little in common with most monsoons, and its dynamics may be affected most by Tibet's lying in the path of the subtropical jet stream. Although the growing plateau surely altered Asian climate during Cenozoic time, the emerging view of its role in present-day climate opens new challenges for interpreting observations of both paleoclimate and modern climate.