Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published July 2019 | public
Journal Article

The direct and ocean-mediated influence of Asian orography on tropical precipitation and cyclones


Prior global climate model (GCM) experiments have shown that the Tibetan Plateau and related orography play a significant role in enhancing the Indian Monsoon, particularly during its onset, and the East Asian monsoon. However, these experiments have been largely performed with atmosphere-only, lower-resolution GCMs that neglect the influence of atmosphere–ocean coupling, and do not resolve tropical cyclones (TCs). Here we explore the influence of Asian orography on tropical circulations in a Geophysical Fluid Dynamics Laboratory GCM at two different atmosphere/land resolutions (∼50 and 200 km), and with or without atmosphere–ocean coupling. Atmosphere–ocean coupling is found to play a significant role in the precipitation response due to the Asian orography, enhancing the precipitation increase over the Western North Pacific (hereafter WNP), and drying the Arabian Sea. In these same regions, the higher resolution model, which resolves TCs up to category 3, suggests that Asian orography has a significant influence on TCs, increasing TC frequency in the WNP, and decreasing it in the Arabian Sea. However, in contrast to precipitation, this TC response does not appear to be strongly affected by the atmosphere–ocean coupling. Connections between the direct atmospheric circulation response to Asian orography, ocean circulation changes, and these various effects on precipitation and tropical cyclones are analyzed and discussed.

Additional Information

© 2019 Springer-Verlag GmbH Germany, part of Springer Nature. Received: 8 June 2018; Accepted: 4 January 2019; First Online: 29 January 2019. JWB and GAV were funded by the NOAA Climate Program Office, and JWB was also funded by a National Science Foundation Graduate Research Fellowship (DGE 1148900). Hiroyuki Murakami, Tom Delworth, Isaac Held, Chris Milly, Bill Boos, and Kerry Emanuel provided useful feedback at various stages of the project, and Seth Underwood, William Cooke, and Sergey Malyshev provided critical technical support. Two anonymous reviewers also provided thoughtful feedback which greatly improved this work. The AM2.1 simulation data was supplied by Ho-Hsuan Wei. The calculation of tropical cyclone genesis potential was significantly aided by scripts provided by Hiroyuki Murakami, for which the fortran subroutine made available online by Kerry Emanuel was used (see https://emanuel.mit.edu/products). We acknowledge the World Climate Research Programme's Working Group on Coupled Modelling, which is responsible for CMIP, and we thank the participating climate modeling groups for producing and making available their model output. For CMIP the U.S. Department of Energy's Program for Climate Model Diagnosis and Intercomparison provides coordinating support and led development of software infrastructure in partnership with the Global Organization for Earth System Science Portals.

Additional details

August 22, 2023
October 20, 2023