Convective rain cell properties and the resulting precipitation scaling in a warm-temperate climate

  • Convective precipitation events have been shown to intensify at rates exceeding the Clausius–Clapeyron rate (CC rate) of ca. 7% K−1 under current climate conditions. In this study, we relate atmospheric variables (low-level dew point temperature, convective available potential energy, and vertical wind shear), which are regarded as ingredients for severe deep convection, to properties of convective rain cells (cell area, maximum precipitation intensity, lifetime, precipitation sum, and cell speed). The rain cell properties are obtained from a rain gauge-adjusted radar dataset in a mid-latitude region, which is characterized by a temperate climate with warm summers (Germany). Different Lagrangian cell properties scale with dew point temperature at varying rates. While the maximum precipitation intensity of cells scales consistently at the CC rate, the area and precipitation sum per cell scale at varying rates above the CC rate. We show that this super-CC scaling is caused by a covarying increase of convective available potential energy with dew point temperature. Wind shear increases the precipitation sum per cell mainly by increasing the spatial cell extent. From a Eulerian point of view, this increase is partly compensated by a higher cell velocity, which leads to Eulerian precipitation scaling rates close to and slightly above the CC rate. Thus, Eulerian scaling rates of convective precipitation are modulated by convective available potential energy and vertical wind shear, making it unlikely that present scaling rates can be applied to future climate conditions. Furthermore, we show that cells that cause heavy precipitation at fixed locations occur at low vertical wind shear and, thus, move relatively slowly compared to typical cells.

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Author:Christopher PurrORCiDGND, Erwan BrissonORCiD, Katharina Heinke SchlünzenORCiDGND, Bodo AhrensORCiDGND
Parent Title (English):Quarterly Journal of the Royal Meteorological Society
Place of publication:Weinheim [u.a.]
Document Type:Article
Date of Publication (online):2022/04/05
Date of first Publication:2022/04/05
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/10/05
Tag:Clausius–Clapeyron scaling; convective storms; precipitation; tracking
Page Number:14
First Page:1768
Last Page:1781
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.
Institutes:Geowissenschaften / Geographie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften
Licence (German):License LogoCreative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International