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Keywords:

  • rainfall;
  • trend;
  • tropical cyclone

[1] In this study, we use Tropical Rainfall Measurement Mission and Global Precipitation Climatology Project rainfall data together with historical storm track records to examine the trend of tropical cyclone (TC) rainfall in the North Atlantic and the northeast and northwest Pacific during two recent decades (1988–1997 and 1998–2007). We find that there is an approximate linear relationship between TC rain (defined as accumulated total rainfall along storm tracks) and storm intensity as classified by the Saffir-Simpson scheme. During the data period, total TC rain has trended upward at a rate of 23.8% ± 23.5% per decade over the North Atlantic but downward with a rate of 25.1% ± 19.7% per decade over the northeast Pacific. Over the northwest Pacific, there is a reduction in TC rain of approximately 20.9% ± 13.5% per decade, possibly associated with a strong interdecadal-scale oscillation. Storm characteristics such as duration and TC rain energy per storm (EPS) remain unchanged for the North Atlantic and the northeast Pacific. For the northwest Pacific, a 28% ± 18% reduction in EPS from the first decade (1988–1997) to the second decade (1998–2007) is found with the track data from the Joint Typhoon Warning Center. Analyses of the probability distribution function of TC rain show that there is an overall increase in TC frequency across the entire TC rainfall spectrum over the North Atlantic but an overall decrease for the northeast Pacific. In the northwest Pacific, we find a redistribution in EPS with decreased frequency in heavy-rain storms and increased frequency in light-rain storms. Overall, trends in TC rain in the different ocean basins are consistent with long-term relative changes in the ambient large-scale sea surface temperature and vertical wind shear and, to a lesser extent, tropical cyclone Maximum Potential Intensity.