Changes in the Character of Heavy Precipitation Events with Warming

Increases in the frequency of heavy precipitation events have been related to climate warming. Some investigators have analyzed the precipitation changes, separating thermodynamic from dynamic influences. Here, we extend this research to analyze changes in vertical motion, horizontal moisture transport, and rain rates for heavy rainfall events in current and future climate regimes using a high-resolution downscaling approach.

Simulations of current and future flooding events are undertaken using the “pseudo global warming” method. The south-central US flood of May, 2010, extratropical storm Xynthia (2010), an idealized tropical cyclone, and transitioning tropical storm Nicole (2010) are simulated and analyzed for current and future conditions with the goal of identifying changes in the character of the rainfall. Histograms of rain rate exhibit a marked decrease in the grid-cell frequency of lighter precipitation frequency and a larger frequency of grid cells experiencing heavier rain in future relative to current conditions.