Uncertainty in estimating the observed relationship between hourly precipitation extremes and dewpoint temperature

Short-duration (hourly) precipitation extremes have intensified in the past and they are projected to increase more under the warming climate. The Clausius-Clapeyron (CC) relationship can be used to understand the sensitivity (scaling) of precipitation extremes with warming. According to the CC relationship, hourly precipitation extremes intensify at around a 7% (CC rate) per degree rise in temperature. However, the observed scaling rates deviate from the CC rate which can be due to multiple thermodynamic and dynamic factors which have been discussed in the recent scaling studies. Moreover, the choice of data and scaling methods may also lead to uncertainty in scaling rates. In this study, by using observed hourly precipitation and daily dewpoint temperature over the USA, we show that robust quality controlled precipitation data show differences in scaling. We also obtained higher scaling rates for the higher measurement precision data (0.25mm and 2.5mm). We further show the uncertainty in scaling rates using different four scaling methods. Our results highlight the need of using extensive quality controlled and finer precision observations for estimating accurate scaling rates.