On 5 December 2015, the GRIPS 14 instrument (GRound-based Infrared P-branch Spectrometer) began to measure mesopause temperatures for the GW-LCYCLE campaign (Investigation of the life cycle of gravity waves) at ALOMAR (Arctic Lidar Observatory for Middle Atmosphere Research), Norway. This site is on Andoya island north of the polar circle on the premises of the Andoya Air Station, near the town of Andenes. The mesopause temperatures are derived from the spectra of the hydroxyl (OH) that forms a natural, shining layer at ca. 90 km altitude known as airglow.
This returns what is now the tenth instrument in a product series developed at DFD to the location where one of its predecessors successfully participated from 2010 to 2014 in the first inter-comparison and calibration campaign of the Network for the Detection of Mesospheric Change (NDMC), coordinated by DFD.
As part of the GW-LCYCLE project sponsored by the German Ministry of Education and Research, the propagation of atmospheric gravity waves is being investigated in this campaign. These waves in the troposphere frequently arise near mountains and can spread out over large distances horizontally as well as vertically, transporting momentum and energy in the process. Studying them is crucial for improving understanding of large-scale atmospheric airflow systems.
In this project, two DLR research aircraft, FALCON and HALO will take off from Kiruna, Sweden in January 2016 in order to undertake measurements at various altitudes over Scandinavian mountain ranges. In addition to ground-based instruments, an innovative DFD camera on board the FALCON will provide high-resolution images of gravity waves in the OH airglow. Combining the in-situ measurements with those made on board both aircraft makes it possible to monitor gravity waves from their excitation in the troposphere to their expansion through the stratosphere and up into the upper mesosphere—the region of increased dissipation. The participating scientists are hoping that their use of the various measuring instruments and the acquired parameters will lead to significant progress in understanding gravity waves and the associated atmospheric response. The science activities are being carried out also in cooperation with the Chair for Remote Sensing of the Atmosphere at Augsburg University.