TY - JOUR
T1 - Impact of atmospheric changes on the low-frequency variations of convective afternoon rainfall activity over Taiwan
AU - Huang, Wan Ru
AU - Hsu, Huang Hsiung
AU - Wang, Shih Yu
AU - Chen, Jian Pu
N1 - Funding Information:
The JRA-55 data provided by Japan Meteorological Agency can be accessed at http://jra.kishou.go.jp/JRA-55/ index_en.html and the 3-hourly surface observations provided by Central Weather Bureau in Taiwan can be accessed at https://dbar.ttfri.narl.org.tw/. The authors thank anonymous reviewers for their comments and suggestions which greatly improved the manuscript. This research was supported by the Ministry of Science and Technology of Taiwan under MOST 104-2111-M-003-001, MOST 103-2111-M-003-001, MOST 103-2621-M-865 -001, and MOST 100-2119-M-001 -029 -MY5.
Publisher Copyright:
© 2015. The Authors.
PY - 2015
Y1 - 2015
N2 - 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.
AB - 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.
KW - Changes in atmospheric modulations led to differences in the CAR frequency
KW - Changes in moisture flux convergence led to differences in the CAR rate
KW - Trend in convective rainfall activity (CAR) in Taiwan is regional dependent
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U2 - 10.1002/2015JD023568
DO - 10.1002/2015JD023568
M3 - Article
AN - SCOPUS:84943407156
VL - 120
SP - 8743
EP - 8758
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 17
ER -