TY  - JOUR
A1  - Purr, Christopher
A1  - Brisson, Erwan
A1  - Ahrens, Bodo
T1  - Convective rain cell characteristics and scaling in climate projections for Germany
T2  - International journal of climatology
N2  - Extreme convective precipitation is expected to increase with global warming. However, the rate of increase and the understanding of contributing processes remain highly uncertain. We investigated characteristics of convective rain cells like area, intensity, and lifetime as simulated by a convection-permitting climate model in the area of Germany under historical (1976–2005) and future (end-of-century, RCP8.5 scenario) conditions. To this end, a tracking algorithm was applied to 5-min precipitation output. While the number of convective cells is virtually similar under historical and future conditions, there are more intense and larger cells in the future. This yields an increase in hourly precipitation extremes, although mean precipitation decreases. The relative change in the frequency distributions of area, intensity, and precipitation sum per cell is highest for the most extreme percentiles, suggesting that extreme events intensify the most. Furthermore, we investigated the temperature and moisture scaling of cell characteristics. The temperature scaling drops off at high temperatures, with a shift in drop-off towards higher temperatures in the future, allowing for higher peak values. In contrast, dew point temperature scaling shows consistent rates across the whole dew point range. Cell characteristics scale at varying rates, either below (mean intensity), at about (maximum intensity and area), or above (precipitation sum) the Clausius–Clapeyron rate. Thus, the widely investigated extreme precipitation scaling at fixed locations is a complex product of the scaling of different cell characteristics. The dew point scaling rates and absolute values of the scaling curves in historical and future conditions are closest for the highest percentiles. Therefore, near-surface humidity provides a good predictor for the upper limit of for example, maximum intensity and total precipitation of individual convective cells. However, the frequency distribution of the number of cells depending on dew point temperature changes in the future, preventing statistical inference of extreme precipitation from near-surface humidity.
KW  - Clausius–Clapeyron scaling
KW  - convection-permitting simulation
KW  - convective storms
KW  - COSMO-CLM
KW  - precipitation
KW  - tracking
Y1  - 2021
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/62231
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-622318
SN  - 1097-0088
N1  - We thank the Hessisches Landesamt für Naturschutz, Umwelt und Geologie, and the Rheinland-Pfalz Kompetenzzentrum für Klimawandelfolgen for funding the project ‘Konvektive Gefährdung über Hessen und Rheinland-Pfalz’ in the course of which the results of this paper were obtained. The simulations were performed on the LOEWE-CSC high-performance computer of Frankfurt University. Open Access funding enabled and organized by ProjektDEAL.
VL  - 41
IS  - 5
SP  - 3174
EP  - 3185
PB  - Wiley
CY  - Chichester [u.a.]
ER  -