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Linear and Nonlinear Hydrological Cycle Responses to Increasing Sea Surface Temperature
Author(s) -
Toda Masaki,
Watanabe Masahiro
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076745
Subject(s) - sea surface temperature , climatology , precipitation , environmental science , anomaly (physics) , magnitude (astronomy) , common spatial pattern , atmospheric sciences , geology , meteorology , physics , mathematics , statistics , astronomy , condensed matter physics
An effective mechanism for determining tropical rainfall patterns in response to sea surface temperature (SST) increases with varying magnitude and horizontal distribution has not been developed thus far in climate change studies. In order to examine changes in precipitation pattern with increasing SST, we conducted a series of atmospheric general circulation model experiments using a 30 year record of observed SST for which either globally uniform SST increases of 1 K, 2 K, and 4 K or El Niño/La Niña‐like patterned SST anomaly has been imposed. Although the global‐mean precipitation linearly increases with the SST increase irrespective of its spatial distribution, regional precipitation changes were found to occur nonlinearly depending on the magnitude of the uniform SST increase. Owing to nonlinearity in the atmospheric circulation response, the regional hydrological sensitivity was larger with a smaller increase in SST. The precipitation response to the SST pattern was, however, quasi‐linear to the magnitude of the SST change and can be separated from the response to the uniform SST increase. This study thus emphasizes the importance of relative amplitudes of uniform and structured SST increases for future rainfall projection.