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Precipitation under Subtropical High Conditions: Evidence and Implications |
FENG Sha,LIU Qi,FU Yun-Fei |
Laboratory of Satellite Remote Sensing and Climate Environment, University of Science and Technology of China, Hefei 230026, China,Laboratory of Satellite Remote Sensing and Climate Environment, University of Science and Technology of China, Hefei 230026, China,Laboratory of Satellite Remote Sensing and Climate Environment, University of Science and Technology of China, Hefei 230026, China; LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 |
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Abstract The impact of the subtropical high (STH) on precipitation was investigated on a daily timescale using matched NCEP and the Global Precipitation Climatology Project (GPCP) datasets. Comparison of the conditional probability (intensity) of precipitation under STH conditions with that under non-STH conditions suggests that the presence of the STH conditions has a limited impact on local precipitation. In the West Pacific Subtropical High (WPSH) and the North Atlantic Subtropical High (NASH), precipitation was only 30% lower under STH conditions than under non-STH conditions. The STH conditions had somewhat more impact on precipitation intensity, but it was still 50% less than the intensity under non-STH conditions (mean of roughly 5 mm d1). Precipitation under STH conditions was found to be highly correlated with vertical motion. Active updrafts occurring even under STH conditions are essential for frequent occurrences and moderate intensities of precipitation.
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Received: 14 May 2009
Revised: 19 June 2009
Accepted: 11 July 2009
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