The tropical storm day (TSD) is a combined measure of genesis and lifespan. It reflects tropical cyclone (TC) overall activity, yet its variability has rarely been studied, especially globally. Here we show that the global total TSDs exhibit pronounced interannual (3-6 years) and decadal (10 years) variations over the past five-to-six decades without a significant trend. The leading modes of the interannual and decadal variability of global TSD feature similar patterns in the western Pacific and Atlantic, but different patterns in the Eastern Pacific and the Southern Indian Ocean. The interannual and decadal leading modes are primarily linked to El Ni?o-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), respectively. The TSDs-ENSO relationship has been steady during the entire 55-year period, but the TSDs-PDO relationship has experienced a breakdown in the 1980s. We find that the decadal variation of TSD in the Pacific is associated with the PDO sea surface temperature (SST) anomalies in the tropical eastern Pacific (PDO-E), while that in the Atlantic and the Indian Ocean is associated with the PDO SST anomalies in the western Pacific (PDO-W). However, the PDO-E and PDO-W SST anomalies are poorly coupled in the 1980s, and this "destructive PDO" pattern results in a breakdown of the TSDs-PDO relationship. The results here have an important implication for seasonal to decadal predictions of global TSD.

Yifei DAI;Bin WANG;Weiyi SUN

Key Laboratory of Meteorological Disaster of Ministry of Education,and Earth System Modeling Center,Nanjing University of Information Science and Technology,Nanjing 210044,China;International Pacific Research Center,University of Hawaii at Manoa,Honolulu,HI 96822,USA;Department of Atmospheric Sciences,School of Ocean and Earth Science and Technology,University of Hawaii at Manoa,Honolulu,HI 96822,USA;Key Laboratory for Virtual Geographic Environment.Ministry of Education,State Key Laboratory Cultivation Base of Geographical Environment Evolution of Jiangsu Province,Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,School of Geography Science,Nanjing Normal University,Nanjing 210023,China

大气科学进展（英文版）

[1]Yifei DAI;Bin WANG;Weiyi SUN-.What Drives the Decadal Variability of Global Tropical Storm Days from 1965 to 2019?)[J].大气科学进展（英文版）,2022(02):344-353

TSDs

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