Impact of large-scale dynamic versus thermodynamic climate conditions on contrasting tropical cyclone genesis frequency

Sur, Sharmila ORCID: and Walsh, K. J. E. (2017) Impact of large-scale dynamic versus thermodynamic climate conditions on contrasting tropical cyclone genesis frequency. Journal of Climate, 30 (22). pp. 8865-8883. ISSN 0894-8755

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Significant advances have been made in understanding the key climate factors responsible for tropical cyclone (TC) activity, yet any theory that estimates likelihood of observed TC formation rates from mean climate states remains elusive. The present study investigates how the extremes of observed TC genesis (TCG) frequency during peak TC seasons are interrelated with distinct changes in the large-scale climate conditions over different ocean basins using the global International Best Track Archive for Climate Stewardship (IBTrACS) dataset and ERA-Interim for the period 1979–2014. Peak TC seasons with significantly high and low TCG frequency are identified for five major ocean basins, and their substantial spatial changes in TCG are noted with regionally distinct differences. To explore the possible climate link behind such changes, a suite of potentially relevant dynamic and thermodynamic climate conditions is analyzed. Results indicate that the observed changes in extreme TCG frequency are closely linked with distinct dominance of specific dynamic and thermodynamic climate conditions over different regions. While the combined influences of dynamic and thermodynamic climate conditions are found to be necessary for modulating TC formation rate over the North Atlantic, eastern Pacific, and southern Indian Oceans, significant changes in large-scale dynamic conditions appear to solely control the TCG frequency over the western Pacific and South Pacific basins. Estimation of the fractional changes in genesis-weighted climate conditions also indicates the coherent but distinct competing effects of different climate conditions on TCG frequency. The present study further points out the need for revising the existing genesis indices for estimating TCG frequency over individual basins.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
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Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 26 Feb 2020 04:37
Last Modified: 02 Jul 2020 03:21
Uncontrolled Keywords: tropics; hurricanes; climate variability; climatology; interannual variability; tropical variability
Fields of Research (2008): 04 Earth Sciences > 0401 Atmospheric Sciences > 040199 Atmospheric Sciences not elsewhere classified
04 Earth Sciences > 0401 Atmospheric Sciences > 040107 Meteorology
Fields of Research (2020): 37 EARTH SCIENCES > 3701 Atmospheric sciences > 370199 Atmospheric sciences not elsewhere classified
37 EARTH SCIENCES > 3701 Atmospheric sciences > 370108 Meteorology
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