Lidar-Based Height Correction for the Assimilation of Atmospheric Motion Vectors

Author(s)
Kathrin Folger, Martin Weissmann, Martin Weissmann
Abstract

This study uses lidar observations from the polar-orbiting Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite to correct operational atmospheric motion vector (AMV) pressure heights. This intends to reduce the height assignment error of AMVs for their use in data assimilation. Additionally, AMVs are treated as winds in a vertical layer as proposed by several recent studies. Corrected and uncorrected AMV winds are evaluated using short-term forecasts of the global forecasting system of the German Weather Service. First, a direct lidar-based height reassignment of AMVs with collocated CALIPSO observations is evaluated. Assigning AMV winds from Meteosat-10 to ~120-hPa-deep layers below the lidar cloud top reduces the vector root-mean-square (VRMS) differences of AMVs from Meteosat-10 by 8%–15%. However, such a direct reassignment can only be applied to collocated AMV–CALIPSO observations that compose a comparably small subset of all AMVs. Second, CALIPSO observations are used to derive statistical height bias correction functions for a general height correction of all operational AMVs from Meteosat-10. Such a height bias correction achieves on average about 50% of the reduction of VRMS differences of the direct height reassignment. Results for other satellites are more ambiguous but still encouraging. Given that such a height bias correction can be applied to all AMVs from a geostationary satellite, the method exhibits a promising approach for the assimilation of AMVs in numerical weather prediction models in the future.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
Ludwig-Maximilians-Universität München, Hans-Ertel-Zentrum für Wetterforschung
Journal
Journal of Applied Meteorology and Climatology
Volume
55
Pages
2211-2227
No. of pages
17
ISSN
1558-8424
DOI
https://doi.org/10.1175/JAMC-D-15-0260.1
Publication date
2016
Peer reviewed
Yes
Austrian Fields of Science 2012
105206 Meteorology
Keywords
ASJC Scopus subject areas
Atmospheric Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/lidarbased-height-correction-for-the-assimilation-of-atmospheric-motion-vectors(d3f2ce8d-0594-475c-907e-a95dde5989c1).html