Journal Article

FZJ-2015-00869

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Mixing-layer height retrieval with ceilometer and Doppler lidar: from case studies to long-term assessment

Schween, J. H. (Corresponding Author) ; Hirsikko, A.FZJ* ; Löhnert, U.FZJ* ; Crewell, S.

2014
Copernicus Katlenburg-Lindau

This record in other databases:    

Please use a persistent id in citations: http://hdl.handle.net/2128/8301  doi:10.5194/amt-7-3685-2014

Abstract: Aerosol signatures observed by ceilometers are frequently used to derive mixing-layer height (MLH) which is an essential variable for air quality modelling. However, Doppler wind lidar measurements of vertical velocity can provide a more direct estimation of MLH via simple thresholding. A case study reveals difficulties in the aerosol-based MLH retrieval during transition times when the mixing layer builds up in the morning and when turbulence decays in the afternoon. The difficulties can be explained by the fact that the aerosol distribution is related to the history of the mixing process and aerosol characteristics are modified by humidification. The results of the case study are generalized by evaluating one year of joint measurements by a Vaisala CT25K and a HALO Photonics Streamline wind lidar. On average the aerosol-based retrieval gives higher MLH than the wind lidar with an overestimation of MLH by about 300 m (600 m) in the morning (late afternoon). Also, the daily aerosol-based maximum MLH is larger and occurs later during the day and the average morning growth rates are smaller than those derived from the vertical wind. In fair weather conditions classified by less than 4 octa cloud cover the mean diurnal cycle of cloud base height corresponds well to the mixing-layer height showing potential for a simplified MLH estimation.

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Contributing Institute(s):

1. Troposphäre (IEK-8)

Research Program(s):

1. 233 - Trace gas and aerosol processes in the troposphere (POF2-233) (POF2-233)

Appears in the scientific report 2014

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Database coverage:
; ; ; ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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