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

Abstract

Hourly precipitation extremes can intensify with temperature at higher rates than expected from thermodynamic increases explained by the Clausius‐Clapeyron (CC) relationship (∼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 × CC at more than 60% of gauges, peaking in the tropics at a median rate of ∼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.

Global Scaling of Rainfall With Dewpoint Temperature Reveals Considerable Ocean‐Land Difference

“…However, recent work by Ali et al. (2021) has shown consistent scaling at the CC‐rate globally. Using hourly observations of rainfall at 7,000 gauges from the Global Subdaily Rainfall (GSDR) data set (Lewis et al., 2019) across six macroregions, they established a consistent scaling relationship with dewpoint temperature overland at around the CC rate, when averaged over large regions, and at around 2CC locally.…”

“…We first estimated the scaling rates using climate reanalysis data for the locations where GSDR data are available. The scaling results using the GSDR data are the same as those presented in Figure 1 in Ali et al (2021) and therefore not as thoroughly discussed here.…”

“…The physical causes of this diversity in scaling are still under discussion (Bao et al, 2017;Barbero et al, 2018). Differences in scaling rates have been reported to occur from processes varying from the microscale to the synoptic scale (Fowler, Lenderink, et al, 2021). Important compounding factors include changes to moisture availability (Barbero et al, 2018;Peleg et al, 2018), the intermittent nature of precipitation (Schleiss, 2018;Visser et al, 2020), temperature seasonality (Zhang et al, 2017), different rainfall types (Molnar et al, 2015), and large-scale circulation dynamics (Magan et al, 2020;Pfahl et al, 2017).…”

“…Important compounding factors include changes to moisture availability (Barbero et al, 2018;Peleg et al, 2018), the intermittent nature of precipitation (Schleiss, 2018;Visser et al, 2020), temperature seasonality (Zhang et al, 2017), different rainfall types (Molnar et al, 2015), and large-scale circulation dynamics (Magan et al, 2020;Pfahl et al, 2017). However, recent work by Ali et al (2021) has shown consistent scaling at the CC-rate globally. Using hourly observations of rainfall at 7,000 gauges from the Global Subdaily Rainfall (GSDR) data set (Lewis et al, 2019) across six macroregions, they established a consistent scaling relationship with dewpoint temperature overland at around the CC rate, when averaged over large regions, and at around 2CC locally.…”

Quasi‐Stationary Intense Rainstorms Spread Across Europe Under Climate Change

“…Higher moisture availability in the atmosphere with warming has been extensively studied and partially explains the observed and simulated rise in short‐duration precipitation extremes, with stronger updrafts also potentially contributing (Giorgi et al., 2016; Held & Soden, 2006; O’Gorman & Schneider, 2009). Many studies have reported increases in precipitation extremes with temperature following the Clausius‐Clapeyron (CC) rate of 7% per K (Ali et al., 2021; Visser et al., 2020). However, higher scaling rates (so called ‘super‐CC scaling’) have been found for hourly precipitation extremes (Ban et al., 2015; Berg et al., 2013; Drobinski et al., 2018; Hodnebrog et al., 2019; Lenderink & van Meijgaard, 2008; van de Vyver et al., 2019).…”