This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The Investigator will develop a simple, effective, and inexpensive method of obtaining very high-vertical-resolution atmospheric measurements made in close proximity to the SOUSY radar beam in Jicamarca Peru (a NSF Upper Atmospheric Facilities funded center). To make these measurements, the Principal Investigator (PI) will use a GPS-controlled mini-glider (Databird) that will be lifted to altitude using a meteorological balloon.
Following its release at altitude, the Databird will be programmed to glide to the radar beam coordinates and then descend in a tight spiral around the radar antenna to provide a high-resolution potential temperature profile virtually in line with the radar beam. These potential temperature profiles will be used in conjunction with radar obtained profiles of wind speed to produce profiles of the local gradient Richardson number (Ri). The resulting Ri profile will then be compared with concurrently-measured radar echo profiles to determine the relationship between the turbulence-related echo strengths and local dynamic instability criteria (Ri < 0.25). Results from this initial study have the potential to provide new insights into the important relationship between local dynamic instability profiles and turbulence echoes.
An additional important feature provided by the Databird measurements will be to obtain information on recently-discovered atmospheric "overturning" events. These events are visible in the potential temperature profiles and occur on vertical scales of tens to hundreds of meters. Overturnings appear to be a ubiquitous feature in both the troposphere and stratosphere, and probably extend to much higher altitudes. Using the glider system, the investigator will examine the (possibly) causal relationship between overturnings, critical Ri values, and turbulence generation.
The success of this effort will provide first-time high-resolution /vertical/ measurements of the entire lower atmosphere between 0 km and 10 km. Vertical resolution is important in this type of measurement, since most balloon borne data does not provide sufficient information for modelers and theoreticians because (1) the resolution is too poor and since (2) the balloon profiles are typically smeared along-track (wind-driven balloons can be tens of km downwind be the time they reach useful operating heights). Therefore, one can anticipate that the data will be used extensively to improve models and theory as the observing technique matures, and as observations are made at a variety of locations and under a variety of different atmospheric conditions.
The investigator is involving young foreign scientists in Peru in this project. Assuming that the initial tests are as successful, it is possible that larger-scale program involving U.S. graduate students could be initiated. Student participation could include all aspects of the glider design, including higher-height capabilities, field work, analysis techniques, comparisons of results with other types of data and models. Note that implementation of these ideas must await the success of the tests to be conducted with the Databird system.
