Impact of land–sea breezes at different scales on the diurnal rainfall in Taiwan
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The formation mechanism of diurnal rainfall in Taiwan is commonly recognized as a result of local forcings involving solar thermal heating and island-scale land–sea breeze (LSB) interacting with orography. This study found that the diurnal variation of the large-scale circulation over the East Asia-Western North Pacific (EAWNP) modulates considerably the diurnal rainfall in Taiwan. It is shown that the interaction between the two LSB systems—the island-scale LSB and the large-scale LSB over EAWNP—facilitates the formation of the early morning rainfall in western Taiwan, afternoon rainfall in central Taiwan, and nighttime rainfall in eastern Taiwan. Moreover, the post-1998 strengthening of a shallow, low-level southerly wind belt along the coast of Southeast China appears to intensify the diurnal rainfall activity in Taiwan. These findings reveal the role of the large-scale LSB and its long-term variation in the modulation of local diurnal rainfall.
KeywordsDiurnal rainfall Land–sea breeze Circulation change Low-level jet
The authors thank anonymous reviewers for their comments and suggestions which greatly improved the manuscript. This research was supported by the National Science Council of Taiwan under NSC 101-2119-M-003-006-MY2 and NSC 102-2621-M-492-001. SYW was supported by Grant MOTC-CWB-101-M-15, Grant NNX13AC37G, and the Utah Agricultural Experiment Station, Utah State University as Journal Paper # 8464.
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