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Latent Heat Flux Measurements over Complex Terrain by Airborne Water Vapour and Wind Lidars

Kiemle, Christoph and Wirth, Martin and Fix, Andreas and Rahm, Stephan and Corsmeier, Ulrich and Di Girolamo, Paolo (2011) Latent Heat Flux Measurements over Complex Terrain by Airborne Water Vapour and Wind Lidars. Quarterly Journal of the Royal Meteorological Society, 137, pp. 190-203. DOI: 10.1002/qj.757.

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/qj.757/abstract

Abstract

Vertical profiles of the latent heat flux in a convective boundary layer (CBL) are obtained for the first time over complex terrain with airborne water vapour differential absorption lidar and Doppler wind lidar. During the Convective and Orographically-induced Precipitation Study (COPS) over the Black Forest Mountains in south-western Germany both lidars were installed nadir-viewing onboard the Falcon research aircraft of the Deutsches Zentrum f�¼r Luft- und Raumfahrt (DLR). On 30 July 2007, additional in-situ measurements by the Karlsruhe Institute of Technology (KIT) were performed with a Dornier-128 aircraft that flew below the Falcon. This unique instrument configuration allows to validate the lidar-derived fluxes and to assess lidar-specific issues such as instrument noise and data gaps that impinge on the results. The cospectra of in-situ humidity and vertical velocity peak at wavelengths between 1 - 3 km and reveal that the dominant scales of turbulent transport are larger than 700 m in space. Consequently the airborne lidarsâ�� horizontal and vertical resolution of ~200 m is sufficient to seize most of the flux. The lidar and in-situ fluxes of five collocated 45-km flight legs agree within �±20 %, the average difference over the total distance of 225 km is 3 %. A flux comparison with ground-based water vapour Raman and wind lidars shows agreement within the instrumentsâ�� accuracies under low-wind conditions. All latent heat fluxes vary between 100 - 500 W/m�² in the CBL and have small vertical divergences. Vertical velocity spectra in the mid-CBL enable to estimate the dissipation rate of turbulent kinetic energy that amounts to 5â�¢10-4 m2 s-3 in the Rhine Valley and 10-3 m2 s-3 over the Black Forest Mountains. This new airborne lidar instrumentation proves to be a valuable tool for the study of CBL processes and variability, particularly over complex terrain.

Document Type:Article
Title:Latent Heat Flux Measurements over Complex Terrain by Airborne Water Vapour and Wind Lidars
Authors:
AuthorsInstitution or Email of Authors
Kiemle, ChristophDLR IPA
Wirth, MartinDLR IPA
Fix, AndreasDLR IPA
Rahm, StephanDLR IPA
Corsmeier, UlrichKIT IMK
Di Girolamo, PaoloUni Potenza
Date:2011
Journal or Publication Title:Quarterly Journal of the Royal Meteorological Society
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:137
DOI:10.1002/qj.757
Page Range:pp. 190-203
Status:Published
Keywords:turbulent moisture flux, convective boundary layer, differential absorption lidar
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Projekt WALES (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Lidar
Deposited By: Dr.rer.nat. Christoph Kiemle
Deposited On:06 Dec 2010 15:00
Last Modified:12 Dec 2013 20:34

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