On the Threshold Behavior of Extreme Precipitation-Temperature Relationships and Potential Future Changes
In the context of climate variability, the decrease of daily precipitation extremes when local temperature exceeds a certain threshold is a robust characteristic across climate regimes, across different datasets, and across different climate models. This study characterizes the “peak” type extreme precipitation-temperature relationship and evaluates its future changes, and tackles the mechanism underlying the threshold behavior of this relationship. The temperature at which precipitation extreme peaks decreases from the tropics towards high latitudes, and the decrease of extreme precipitation with high temperature (in %/K) is generally faster in the Tropics than extratropics. As climate warms in the future, both the peak of extreme precipitation and the temperature at which it peaks (Tpeak) will increase; the two increases generally conform to the C-C scaling rate in mid- and high-latitudes, and to a super C-C scaling in most of the Tropics. Moreover, the projected increases of Tpeakover land is much slower than the increase of mean temperature (Tmean). As a result, the conventional approach of relating extreme precipitation to Tmean significantly underestimates the scaling rate, producing an apparent sub-C-C scaling.