As natural weather disasters, tropical cyclones (TCs) possess enormous destructiveness related to their intensity (maximum speed of tangential winds in the lower troposphere within 50 km of the TC center). The long-term variability of TC intensity is related to climate change, and it has been found that there has been a considerable increase in the number and proportion of intense TCs over the recent period since satellite observations of TCs have become available.

Change in air temperature is one aspect of climate change. Using reanalysis data, the responses of the North Atlantic, western North Pacific and eastern North Pacific TC peak intensities to tropospheric air temperature have recently been reported in Atmospheric and Oceanic Science Letters by Dr. Zhenxi Zhang from the Inner Mongolia University of Technology, Hohhot, China, and colleagues.

“Air temperatures can affect the peak intensity of TCs over these three basin regions in distinct ways”, says Dr. Zhang.

According to Zhang et al.’s study, significant cooling of the tropopause can strengthen the peak intensity of North Atlantic TCs. However, a strong TC peak intensity for eastern North Pacific TCs is associated with warming in the lower troposphere. The peak intensity of western North Pacific TCs is mainly affected by vertical wind shear, not the atmospheric temperature.

 Main factors affecting the peak intensity of the North Atlantic, western and eastern North Pacific TCs (Credit: Zhenxi Zhang).

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