Influence of tropical cyclones on the estimation of climate variability in the tropical western North Pacific

Huang Hsiung Hsu*, Ching Hui Hung, An Kai Lo, Chun Chieh Wu, Chih Wen Hung

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

76 引文 斯高帕斯(Scopus)

摘要

By estimating the differences between the original and tropical cyclone (TC)-removed fields derived from the 40-yr (ECMWF) Re-Analysis (ERA-40) and NCEP-NCAR 40-Year Reanalysis, this study reveals that TCs contribute significantly (exceeding 50% in certain regions) to the seasonal mean and the intraseasonal and interannual variance of the 850-hPa vorticity along the TC tracks in the tropical western North Pacific. Similar effects on the precipitation are also seen, as presented by the examples located in Taiwan. While the low-frequency, large-scale circulation produces a clustering effect on TCs, the latter, which has a large positive vorticity and tends to occur in the positive vorticity background flow, significantly enhances the strength of the positive vorticity. The contribution from TCs, which is not offset by the synoptic systems with weak negative vorticity, can therefore leave marked footprints in the climate signal and variability. This effect is not removed by long-term averaging and low-pass filtering, which are often used to retrieve the climate perturbations. This study reveals that the climate variability, as it is defined, is not contributed to merely by the low-frequency large-scale fluctuations. Instead, the TC effect has to be taken into account to understand the climate variability in the tropical western North Pacific. Subsequently, the ensemble effect of TCs, at least in the statistical sense, has to be resolved in the climate model to obtain a better simulation of the climate variability in the TC-prone region, such as the tropical western North Pacific.

原文英語
頁(從 - 到)2960-2975
頁數16
期刊Journal of Climate
21
發行號12
DOIs
出版狀態已發佈 - 2008 6月 15
對外發佈

ASJC Scopus subject areas

  • 大氣科學

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