Gravity waves (GWs) extend through great atmospheric depths--under some conditions exceeding 100 km in vertical extent, most notably above major mountain ranges--and embody oscillatory air motions and associated thermodynamic, chemical, microphysical and plasma properties. They are key communicators of momentum and other forms of energy between the lowest and highest reaches of earth's atmosphere. GWs also constitute a significant source of severe turbulence encountered by aircraft, play a role in formation of polar stratospheric clouds that in-turn contribute to ozone destruction, and systematically influence the larger-scale atmospheric circulation. In response to a submitted Scientific Program Overview (SPO) document for the Southern Andes - Antarctic Gravity wave InitiAtive (SAANGRIA) project, this preliminary effort will focus on travel required for coordination of potential SAANGRIA investigators and limited site surveys needed to identify suitable location(s) for operations involving research aircraft, supporting surface-based observations and associated personnel. If ultimately supported, the SAANGRIA field campaign will trace GWs from their generation above orographic escarpments and within active baroclinic zones to their high-altitude breakdown in the mesosphere and thermosphere.
If supported, SAANGRIA will utilize the NSF/NCAR GV aircraft as a platform for combined dropsonde, in situ and remote-sensing measurements of GW generation, propagation and dissipation. The project's intellectual merit is centered on advancing our understanding of GW sources and vertical coupling, GW instabilities and interactions, impacts on Antarctic ozone, and impacts of GW-modulated transport and deposition of momentum on large-scale atmospheric dynamics. Broader impacts of the planned field program will include training of graduate students, increased collaboration and coordination among multiple research agencies and research subdisciplines, improved understanding and forecasts of atmospheric turbulence and airflow, and associated societal benefits.
This NSF funding was awarded to support travel for planning an airborne mission to study the deep propagation of gravity waves in the atmosphere, which have important influences on weather and climate prediction.The program was initially intended to be performed over the Southern Andes and the Antarctic Peninsula. However, logistics forced a change in location, so it was reconfigured to be performed over and around New Zealand and renamed DEEPWAVE. Gravity wave importance derives from their efficient transport of energy and momentum from sources near Earth's surface to very high altitudes, often 100 km or higher. Thus new instruments were built to allow the NSF/NCAR Gulfstream V (GV) research aircraft to measure gravity waves at altitudes from 20 to 100 km, which has never before been done aboard an aircraft. With previous measurement capabilities from 0 to 20 km, the new instruments thus allowed for continuous measurements of gravity waves from the surface to 100 km. A second German research aircraft and extensive ground-based instrumentation made this the most comprehensive experiment ever performed to study gravity wave influences in the atmosphere. The DEEPWAVE program was performed in June and July 2014 and is considered to have been very successful, with many new insights and discoveries expected to arise from subsequent data analysis efforts among the large international team that participated in this fild program.
