Joint Seminar: Airborne Lidar Observations of Water Vapor in the Tropics

Thanks to the capability of performing targeted, simultaneous measurements of atmospheric backscatter and water vapor in regions of particular interest, an airborne water vapor lidar can help elucidate the complex interactions between water vapor, clouds and circulation in the tropics. The DLR WALES (Water vapor Lidar Experiment in Space) lidar was operated on board the German research aircraft HALO during the NARVAL campaigns in December 2013 and in August 2016 in the Northern Atlantic Trades. The measurements show that high horizontal and vertical variability of humidity is omnipresent. Out of the wealth of about 30 winter and 60 summer flight hours totaling 75,000 km of data over the Tropical Atlantic Ocean east of Barbados, several representative lidar segments from different flights are presented, together with satellite imagery and dropsonde profiles. Main advantages of lidar are the capability to detect small-scale vertical moisture gradients and thin dry layers, given the vertical WALES resolution of 300 m, and the capability to obtain profiles within cloud gaps of 3 km minimum size. These unique remote sensing characteristics allow unprecedented insights into water vapor distributions in the vicinity of shallow (trade clouds) and deep convection (ITCZ). Comparisons with models such as the ICON are enabled through analyses in moisture space, sorted from the driest water column to the wettest, in which cloud fraction can be represented as an additional variable. First related findings will be presented.




13:30 h


Geomatikum H3
Lecture Hall H3 (ground floor), University of Hamburg, Bundesstr. 55, Hamburg


Christoph Kiemle, Institute of Atmospheric Physics, DLR


Bjorn Stevens

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