Joint Seminar: How cold is a cold pool?

Cold pools are areas of evaporatively cooled downdraft air that spread on the surface underneath precipitating clouds. Their importance for the development and maintenance of convection is long known. High-resolution Large-Eddy simulations (LES) with a grid spacing of 1km or less are able to explicitly resolve cold pools, however, they lack reference data for an adequate validation. This talk presents results from the analysis of about 500 cold pool passages, recorded at the Hamburg Wettermast site between 2006 and 2019. Negative temperature perturbations range between 2 and 11 K, which is consistent with similar statistics from LES model data. Furthermore, observations show that cold pool intensity systematically varies with available rainwater and atmospheric saturation deficit prior to the cold pool passage. The presented work serves as a first step towards a better characterization of observed cold pools and an improved understanding of how their properties are controlled by environmental factors. Dense observational networks during the planned measurement campaign FESSTVaL (Field Experiment on Submesocale Spatio-Temporal Variability in Lindenberg) in summer 2020 will allow gaining more in-depth insights into the horizontal structure and dynamics of cold pools.

Datum

12.11.2019

Uhrzeit

15:15 Uhr

Ort

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

ReferentIn

Bastian Kirsch

Chair

Dian Putrasahan

Zur Übersicht