Observation of cirrus clouds with GLORIA during the WISE campaign: detection methods and cirrus characterization
-
Published:2021-04-29
Issue:4
Volume:14
Page:3153-3168
-
ISSN:1867-8548
-
Container-title:Atmospheric Measurement Techniques
-
language:en
-
Short-container-title:Atmos. Meas. Tech.
Author:
Bartolome Garcia IreneORCID, Spang ReinholdORCID, Ungermann JörnORCID, Griessbach SabineORCID, Krämer MartinaORCID, Höpfner MichaelORCID, Riese MartinORCID
Abstract
Abstract. Cirrus clouds contribute to the general radiation budget of the Earth and play an important role in climate projections. Of special interest are optically thin cirrus clouds close to the tropopause due to the fact that their impact is not yet well understood. Measuring these clouds is challenging as both high spatial resolution as well as a very high detection sensitivity are needed. These criteria are fulfilled by the infrared limb sounder GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere). This study presents a characterization of observed cirrus clouds using the data obtained by GLORIA aboard the German research aircraft HALO during the WISE (Wave-driven ISentropic Exchange) campaign in September and October 2017. We developed an optimized cloud detection method based on the cloud index and the extinction coefficient retrieved at the microwindow 832.4–834.4 cm−1. We derived macro-physical characteristics of the detected cirrus clouds such as cloud top height, cloud bottom height, vertical extent and cloud top position with respect to the tropopause. The fraction of cirrus clouds detected above the tropopause is on the order of 13 % to 27 %. In general, good agreement with the clouds predicted by the ERA5 reanalysis dataset is obtained. However, cloud occurrence is ≈ 50 % higher in the observations for the region close to and above the tropopause. Cloud bottom heights are also detected above the tropopause. However, considering the uncertainties, we cannot confirm the formation of unattached cirrus layers above the tropopause.
Funder
Deutsche Forschungsgemeinschaft
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference57 articles.
1. Baran, A. J.: The dependence of cirrus infrared radiative properties on ice crystal geometry and shape of the size-distribution function, Q. J. Roy. Meteorol. Soc., 131, 1129–1142, https://doi.org/10.1256/qj.04.91, 2005. a 2. Blank, J.: Tomographic retrieval of atmospheric trace gases observed by GLORIA, PhD thesis, Bergische Universität Wuppertal, Germany, available at: https://juser.fz-juelich.de/record/150342 (last access: 25 March 2021), 2013. a 3. Curtis, A. R.: Discussion of “A statistical model for water vapour absorption” by R. M. Goody, Q. J. Roy. Meteorol. Soc., 78, 638–640, 1952. a 4. Davis, S., Hlavka, D., Jensen, E., Rosenlof, K., Yang, Q. O., Schmidt, S., Borrmann, S., Frey, W., Lawson, P., Voemel, H., and Bui, T. P.: In situ and lidar observations of tropopause subvisible cirrus clouds during TC4, J. Geophys. Res., 115, D00J17, https://doi.org/10.1029/2009JD013093, 2010. a 5. Dessler, A. E.: Clouds and water vapor in the Northern Hemisphere summertime stratosphere, J. Geophys. Res., 114, D00H09, https://doi.org/10.1029/2009JD012075, 2009. a
Cited by
5 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|