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Deep vertical propagation of mountain waves above Scandinavia and New Zealand

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If you have a question about this talk, please contact Dr. Pranab Deb.

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The project “Investigation of the life cycle of gravity waves” (GW-LCYCLE) is part of the German research initiative ROMIC (Role of the Middle atmosphere In Climate) funded by the ministry of research. As milestones of the project, two research campaigns were conducted in northern Scandinavia (December 2013) and in New Zealand (June-November 2014).

In close cooperation with Scandinavian partners as the Stockholm University and the Finnish Meteorological Institute the field program in Scandinavia combined ground-based observations of tropospheric and lower stratospheric flow and stratospheric and mesospheric temperature by lidars and radars at Alomar (Norway) and at Esrange (Sweden) with airborne and balloon-borne observations. Northern Scandinavia was chosen since the westerly flow across the mountains is often aligned with the polar night jet permitting gravity waves to propagate into the middle atmosphere.

During GW-LCYCLE, the atmospheric flow above the Scandinavian mountains was observed under distinct meteorological conditions enabling or attenuating the deep vertical propagation of mountain-induced gravity waves. The presentation juxtaposes two different cases and analyses the associated meteorological conditions. The unique combination of airborne tropospheric wind lidar measurements, flight level data, high-frequency radiosonde profiles and the ground-based lidar observations allow a comprehensive study of deeply propagating gravity waves from the Earth’s surface to the mesosphere.

Our institute also participated in the field phase of DEEPWAVE -NZ (DEEP propagating gravity WAVE experiment over New Zealand) which was conducted in June and July 2014. Key instruments were the NSF /NCAR GV and the DLR Falcon research aircraft, a suite of ground-based instruments, and satellite sensors.

During DEEPWAVE -NZ operational forecasts of the ECMWF ’s integrated forecast system were used to provide guidance for planning the research flights of NSF /NCAR GV and the DLR Falcon during intense observing periods. For certain cases, an astonishing agreement was noticed between the forecasted wave events in the upper atmosphere and observations. Here, operational ECMWF analyses and forecasts are used to characterize the atmospheric state from the Earth’s surface to the mesosphere during the DEEPWAVE field campaign. For selected cases, airborne and ground-based observations are compared with the ECMWF data.

This talk is part of the British Antarctic Survey series.

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