Tropical Cyclone Contribution to Interdecadal Change in Summer Rainfall over South China in the Early 1990s

  • Author(s): Joo-Hong Kim, Chun-Chieh Wu, Chung-Hsiung Sui, and Chang-Hoi Ho
  • DOI: 10.3319/TAO.2011.08.26.01(A)
  • Keywords: Summer rainfall, Tropical cyclone, Interdecadal change, South China

 

Abstract

This study investigated the tropical cyclone (TC) rainfall (PTC) contribution to the interdecadal change in summer (June, July and August) rainfall (PTotal) over South China between 1981 - 1992 (ID1) and 1993 - 2002 (ID2). In an area-averaged sense, the interdecadal change in PTotal was largely attributed to non-TC rainfall for the summer total and months of June and July, while PTC became comparable in August. When the month-to-month spatial variability was considered, noticeable negative PTC contributions showed up over the southeastern coast, Hainan Island, and Taiwan in June and over the southern coastal regions in July. In contrast, a positive PTC contribution spread over South China with its maxima over the southern coastal regions in August, a pattern which appeared to be diametrically opposed to that of the negative PTC contribution in July, though the latter was less significant. The negative PTC contribution over the coastal and insular regions in June and July corresponded to less TC activity there. In June, it was attributed to reduced basin-wide TC activity due to prevailing unfavorable large-scale environments in ID2, whereas, in July, to less TC approaches from the Philippine Sea due to an enhanced cyclonic circulation centered on Taiwan in ID2. Conversely, in August, the overall enhanced positive PTC contribution was mainly by the direct influences of increased TC formations over the South China Sea in ID2.

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