Consistent Large-Scale Response of Hourly Extreme Precipitation to Temperature Variation Over Land

Hourly precipitation extremes can intensify with temperature at higher rates than expected from thermodynamic increases explained by the Clausius-Clapeyron (CC) relationship (similar to 6.5%/K), but local scaling with surface air temperature is highly variable. Here we use daily dew point temperature, a direct proxy of absolute humidity, to estimate at-gauge local scaling across six macro-regions for a global data set of over 7,000 hourly precipitation gauges. We find scaling rates from CC to 2 x CC at more than 60% of gauges, peaking in the tropics at a median rate of similar to 1.5CC. Moreover, regional scaling rates show surprisingly universal behavior at around CC, with higher scaling in Europe. Importantly for impacts, hourly scaling is persistently higher than scaling for daily extreme precipitation. Our results indicate greater consistency in global scaling than previous work, usually at or above CC, with positive scaling in the (sub)tropics. This demonstrates the relevance of DPT scaling to understanding future changes.

Automated summary

The study found that hourly precipitation extremes tend to increase with temperature at rates higher than expected from the Clausius-Clapeyron relationship, with different regions showing varying levels of scaling and Europe having higher scaling rates. Additionally, hourly scaling consistently exceeds scaling for daily extreme precipitation.