Impact of atmospheric changes on the low-frequency variations of convective afternoon rainfall activity over Taiwan

Wan Ru Huang, Huang Hsiung Hsu, Shih Yu Wang, Jian Pu Chen

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

This study examines the characteristics of low-frequency variations (defined as decadal-scale changes) in summer (June-August) convective afternoon rainfall (CAR) activity over Taiwan during 1961-2012. Using 3-hourly rain gauge data, it was found that (1) the CAR frequency exhibits a secular trend and the 10-20 decadal oscillation, (2) the trend in CAR frequency is positive in northern Taiwan but negative in central and southern Taiwan, and (3) the CAR rate increased over most of the lower plains but decreased over themountain range of Taiwan. Diagnoses using the Japanese ReAnalysis (JRA-55) data and surface observations indicate that the low-frequency variations in CAR frequency are closely associated with the variations in monsoon southwesterly winds over the South China Sea and island-wide sea breeze convergence. The regional low-level circulation changes are linked to sea surface temperature anomalies over the Niño-4 region and its 10-20 year (quasi-decadal) oscillation. Regarding the processes that change the CAR rate in the trending patterns, it was found that increases in the moisture flux convergence and the moist (conditional) instability over the lower plains together explain the stronger CAR events in the long run.

Original languageEnglish
Pages (from-to)8743-8758
Number of pages16
JournalJournal of Geophysical Research
Volume120
Issue number17
DOIs
Publication statusPublished - 2015 Jan 1

Keywords

  • Changes in atmospheric modulations led to differences in the CAR frequency
  • Changes in moisture flux convergence led to differences in the CAR rate
  • Trend in convective rainfall activity (CAR) in Taiwan is regional dependent

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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