Dependence of extreme precipitable water events on temperature

Abstract

Recent IPCC reports suggest that the world is getting warmer. Consequently, the concentration of atmospheric water vapor, which determines the water for precipitation, is substantially increasing in accordance with the Clausius-Clapeyron (CC) relationship, which establishes that water vapor in the atmosphere increases at a rate of 7% per ºC of warming. In this study, we explored the relationship between extreme precipitable water events and temperature over the whole globe, its two hemispheres, and the 5º latitudinal bands by using NCEP/NCAR and MERRA-2 reanalysis data for 1980-2017. Our results indicate that extreme precipitable water events linked to temperature basically follow the CC relationship at temperatures roughly below 5 ºC and the sub-CC relationship for temperatures above ~5 ºC, globally and in both hemispheres. The relationship between extreme precipitable water events and temperature over latitudinal regions is not uniform and varies regionally. Our results further indicate that the increasing rate of extreme precipitable water events is higher in the tropics and mid-latitudes of the southern hemisphere than in the northern hemisphere. This study shows the usefulness of the principle of Clausius-Clapeyron relationship to explain extreme precipitable water events linked to temperature.