Changes in Tibetan Plateau latitude as an important factor for understanding East Asian climate since the Eocene: A modeling study

Previous climate modeling studies suggest that the surface uplift of the Himalaya-Tibetan plateau (TP) is a crucial parameter for the onset and intensification of the East Asian monsoon during the Cenozoic. Most of these studies have only considered the Himalaya-TP in its present location between similar to 26 degrees N and similar to 40 degrees N despite numerous recent geophysical studies that reconstruct the Himalaya-TP 10 or more of latitude to the south during the early Paleogene. We have designed a series of climate simulations to explore the sensitivity of East Asian climate to the latitude of the Himalaya-TP. Our simulations suggest that the East Asian climate strongly depends on the latitude of the Himalaya-TP. Surface uplift of a proto-Himalaya-TP in the subtropics intensifies aridity throughout inland Asia north of similar to 40 degrees N and enhances precipitation over East Asia. In contrast, the rise of a proto-Himalaya-TP in the tropics only slightly intensifies aridity in inland Asia north of similar to 40 degrees N, and slightly increases precipitation in East Asia. Importantly, this climate sensitivity to the latitudinal position of the Himalaya-TP is non-linear, particularly for precipitation across East Asia. The simulated precipitation patterns across East Asia are significantly different between our scenarios in which a proto-plateau is situated between similar to 11 degrees N and similar to 25 degrees N and between similar to 20 degrees N and similar to 33 degrees N, but they are similar when the plateau translates northward from between similar to 20 degrees N and similar to 33 degrees N to its modern position. Our simulations, when interpreted in the context of climate proxy data from Central Asia, support geophysically-based paleogeographic reconstructions in which the southern margin of a modern-elevation proto-Himalaya-TP was located at similar to 20 degrees N or further north in the Eocene. (C) 2017 Elsevier B.V. All rights reserved.