CEDAR: Mesospheric Investigation of Gravity Wave and Mountain Wave Activities and Impacts in the Lee Side of the Southern Andes

Utah State University, Logan UT

Investigators

Abstract

This award would support the deployment, installation, and operations of an Advanced Mesospheric Temperature Mapper (AMTM) at Rio Grande, Argentina (53.8 S, 67.7 W) for a three year period. This instrument would use OH emissions to determine the horizontal distribution of the neutral temperature at 85 km over an extent of 300 km square. This site already hosts a meteor wind radar and a Boston University all-sky airglow imager. A new Rayleigh lidar will also be deployed at this site in early 2017 by Dr. B. Kaifler from the German Aerospace Center (DLR). The AMTM operates automatically and with the meteor radar, the Rayleigh lidar, and all-sky imager a suite of 4 complementary data sets enabling unprecedented investigations of the characteristics, propagation and dissipation of atmospheric gravity waves would be created. The combined data sets from these instruments would provide a comprehensive set of accurate measurements of mesospheric winds, temperature, and density that would allow the determination of wave propagation direction and speed with high accuracy and cadence. The research site of Rio Grande is located in the southernmost part of South America. This region (South Andes, Drake Passage and Antarctic Peninsula) has been identified as an enormous gravity wave (GW) 'hotspot'. The mountainous terrain and persistent strong tropospheric winds generate a wealth of GWs including intense orographic waves. The research will help understand the GW lifecycle and effects on the middle and upper atmosphere. The propagation of GWs through the MLT region affects the transformation and exchange of mass, momentum, and energy at the altitudes of 80 to 110 km. Finally, the research will contribute substantially to undergraduate student education within the USA and will lead to new research opportunities for expanded international collaboration. The primary goals of this award are: 1.) To measure the occurrence and characteristics of MWs propagating into the MLT region in the lee side of the Southern Andes Mountains (one of the most intense source regions for MWs) using simultaneous complementary high-quality instruments (DLR Rayleigh lidar, SAAMER meteor radar and BU all-sky imager), 2.) To estimate the impact of MWs on the upper atmosphere, via momentum deposition and compare with the forcing induced by non-orographic wave observed during the same period, 3.) To compare the new results with previous observations involving similar instrumentations but with different orographic sources and atmospheric backgrounds: DEEPWAVE (New Zealand) and GW LCYCLE 2 (Scandinavia).