Global Observational Evidence of Strong Linkage Between Dew Point Temperature and Precipitation Extremes

Using global station-based observations of precipitation, near-surface air temperature (SAT), and dew point temperature (DPT), we show that the negative scaling relationship found between extreme daily precipitation and SAT over the tropics is associated with the low seasonality in temperature. When using a binning technique or quantile regression, not accounting for seasonality in temperature produces a negative scaling for the majority of stations in the tropics, with higher temperatures associated with smaller precipitation extremes. After removing temperature seasonality, we find that most locations show a positive (median 5.2%/K) scaling with SAT and 96% of global locations exhibit positive (median 6.1%/K) scaling with DPT. Moreover, about 33% (22%) of the locations show super C-C scaling (higher than 7%/K) with DPT (SAT). Our results show that the impact of warming on extreme precipitation (especially over the tropics) may be higher than previously thought. Plain Language Summary Extreme precipitation events have increased during the recent decades and are likely to increase under the warming climate. Understanding the role of changes in air temperature on extreme precipitation events is important for the risk assessment and planning of infrastructure. Using station-based observations of precipitation, air temperature, and dew point temperature, we show that precipitation extremes increase with the rise of local temperature in the majority of regions. However, precipitation extremes are negatively correlated with surface air temperature over the tropics mainly due to the effect of seasonality and relative humidity. We show that the dew point temperature is a more robust indicator of changes in precipitation extremes in comparison to surface air temperature.