Journal
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Volume 121, Issue 7, Pages 3100-3119Publisher
AMER GEOPHYSICAL UNION
DOI: 10.1002/2015JD023497
Keywords
precipitation extremes; water vapor saturation; precipitation efficiency; Clausius-Clapeyron relationship; regional climate; Mediterranean
Categories
Funding
- INSU-MISTRALS
- French National Research Agency (ANR) [ANR-12-SENV-001, ANR-12-JS06-0005]
- IPSL group for regional climate and environmental studies
- Chair for Sustainable Development at Ecole Polytechnique
Ask authors/readers for more resources
Expected changes to future extreme precipitation remain a key uncertainty associated with anthropogenic climate change. Extreme precipitation has been proposed to scale with the precipitable water content in the atmosphere. Assuming constant relative humidity, this implies an increase of precipitation extremes at a rate of about 7%degrees C-1 globally as indicated by the Clausius-Clapeyron relationship. Increases faster and slower than Clausius-Clapeyron have also been reported. In this work, we examine the scaling between precipitation extremes and temperature in the present climate using simulations and measurements from surface weather stations collected in the frame of the HyMeX and MED-CORDEX programs in Southern France. Of particular interest are departures from the Clausius-Clapeyron thermodynamic expectation, their spatial and temporal distribution, and their origin. Looking at the scaling of precipitation extreme with temperature, two regimes emerge which form a hook shape: one at low temperatures (cooler than around 15 degrees C) with rates of increase close to the Clausius-Clapeyron rate and one at high temperatures (warmer than about 15 degrees C) with sub-Clausius-Clapeyron rates and most often negative rates. On average, the region of focus does not seem to exhibit super Clausius-Clapeyron behavior except at some stations, in contrast to earlier studies. Many factors can contribute to departure from Clausius-Clapeyron scaling: time and spatial averaging, choice of scaling temperature (surface versus condensation level), and precipitation efficiency and vertical velocity in updrafts that are not necessarily constant with temperature. But most importantly, the dynamical contribution of orography to precipitation in the fall over this area during the so-called Cevenoles events, explains the hook shape of the scaling of precipitation extremes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available