Dependency of vertical velocity variance on meteorological conditions in the convective boundary layer
- Measurements of vertical velocity from vertically pointing Doppler lidars are used to derive the profiles of normalized vertical velocity variance. Observations were taken during the FESSTVaL (Field Experiment on Submesoscale Spatio-Temporal Variability in Lindenberg) campaign during the warm seasons of 2020 and 2021. Normalized by the square of the convective velocity scale, the average vertical velocity variance profile follows the universal profile of Lenschow et al. (1980). However, daily profiles still show a high day-to-day variability. We found that moisture transport and the content of moisture in the boundary layer could explain the remaining variability of the normalized vertical velocity variance. The magnitude of the normalized vertical velocity variance is highest on clear-sky days and decreases as the absolute humidity increases and surface latent heat flux decreases on cloud-topped days. This suggests that moisture content and moisture transport are limiting factors for the intensity of turbulence in the convective boundary layer. We also found that the intensity of turbulence decreases with an increase in the boundary layer cloud fraction during FESSTVaL, while the latent heating in the cloud layer was not a relevant source of turbulence in this case. We conclude that a new vertical velocity scale has to be defined that would take into account the moist processes in the convective boundary layer.
Author: | Noviana DewaniORCiD, Mirjana SakradzijaORCiD, Linda SchlemmerORCiDGND, Ronny LeinweberORCiD, Jürg SchmidliORCiDGND |
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URN: | urn:nbn:de:hebis:30:3-864694 |
DOI: | https://doi.org/10.5194/acp-23-4045-2023 |
ISSN: | 1680-7324 |
Parent Title (English): | Atmospheric chemistry and physics |
Publisher: | European Geosciences Union |
Place of publication: | Katlenburg-Lindau |
Document Type: | Article |
Language: | English |
Date of Publication (online): | 2023/04/05 |
Date of first Publication: | 2023/04/05 |
Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
Release Date: | 2024/08/06 |
Volume: | 23 |
Issue: | 7 |
Page Number: | 14 |
First Page: | 4045 |
Last Page: | 4058 |
Institutes: | Medizin |
Geowissenschaften / Geographie / Geowissenschaften | |
Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit | |
Sammlungen: | Universitätspublikationen |
Licence (German): | Creative Commons - CC BY - Namensnennung 4.0 International |