Recent global decrease in the inner-core rain rate of tropical cyclones

Heavy rainfall is one of the major aspects of tropical cyclones (TC) and can cause substantial damages. Here, we show, based on satellite observational rainfall data and numerical model results, that between 1999 and 2018, the rain rate in the outer region of TCs has been increasing, but it has decreased significantly in the inner-core. Globally, the TC rain rate has increased by 84% during this period, which is mainly contributed by an increase in rain rate in the TC outer region due to increasing water vapor availability in the atmosphere with rising surface temperature. On the other hand, the rain rate in the inner-core of TCs has decreased by 24 +/- 3% during the same period. The decreasing trend in the inner-core rain rate likely results mainly from an increase in atmospheric stability. How the rainfall intensity of tropical cyclones changes with climate change is not well known. Here, the authors show that while the rain rate in the outer region of TCs is clearly increasing between 1999 and 2018, it decreases significantly in the inner-core of TCs during 1999-2018.

Automated summary

Studies have shown that the rainfall rate in the outer region of tropical cyclones has been increasing in the past twenty years, while it has significantly decreased in the inner-core region. Globally, the increase in TC rain rate is mainly attributed to the rising water vapor availability in the atmosphere.