Basin-Specific Changes and Intensity of Tropical Cyclones

Abstract

The 1990-2024 North Atlantic trend in the proportion of major-cyclone Category 3-5 fixes among all Category 1-5 fixes (the Kossin ratio, KR) was about five times the combined Pacific trend. This contrast motivates examining their basin-specific links: aerosol loading to cyclone potential intensity, and potential intensity to observed cyclone activity. Annual increases in aerosol loading were generally associated with decreasing potential intensity both in the North Atlantic and in all three Pacific basins. Potential intensity changes were consistently positively associated with cyclone-fix count changes in the North Atlantic, in some specifications also in the eastern North Pacific and South Pacific. However, changes in potential intensity in the western North Pacific were significantly negatively correlated with fix-count changes. The negative association disappeared after controlling for El Niño-Southern Oscillation changes. Furthermore, annual potential intensity changes were never significantly positively associated with KR changes.