Relationship of extreme precipitation, dry-bulb temperature, and dew point temperature across Australia

Abstract

Precipitation extremes are expected to intensify due to an increased moisture holding capacity in the atmosphere with higher temperatures; according to the Clausius-Clapeyron (CC) relation this increase is approximately 7% for every degree increase in temperature. Contrary to expectation, the relationship between precipitation extremes and surface temperature often differs from 7%/◦C. Here, we explore this relationship further by estimating the sensitivity of precipitation with both dry-bulb temperature and dew point temperature across Australia. A much better correspondence to the CC relation is obtained when surface dew point temperature is used for the calculation of precipitation-temperature sensitivities instead of surface dry-bulb temperature with most sites exhibiting sensitivities close to, or in excess of, the CC relation. The sensitivity obtained using dew point temperature is more consistent across climatic region, precipitation duration, and precipitation percentile. We conclude that dew point temperature is a better measure of precipitation changes due to increases in atmospheric moisture than dry-bulb temperature.