Observed response of precipitation intensity to dew point temperature over the contiguous US

Abstract

Precipitation has an important impact on crop growth, water resources, industrial/agricultural production, and ecological services. Compared to widely used precipitation amount, intensity of precipitation is more important because it determines the partition of precipitation into soil moisture and surface runoff. With hourly precipitation observations collected at 307 stations over the contiguous US from 1984 to 2013, this study investigates the sensitivity of precipitation intensity to warming. To deal with the issues of constant relative humidity assumption in the existing studies, the sensitivities of hourly precipitation intensity at various percentiles to dew point temperature are examined. We find that the results with dew point temperature showed more consistent and robust positive sensitivities than that of air temperature. The sensitivity of precipitation intensity to warming of dew point temperature increases from ~2%/°C for the 50th percentile of precipitation to ~6%/°C for the 99th percentile of precipitation. These sensitivities are the largest in the Southwest region, followed by the Great Lakes and Plains, the Pacific Coast, and the West region. Such spatial contrast is the largest in summer. The results can provide a comprehensive and quantitative documentation of the precipitation sensitivity to warming.