Stormin’ the Atmosphere with Unmanned Aircraft Systems: Early Results From LAPSE-RATE and Lessons Learned

We are witnessing a rapid increase in interest among researchers in the use of unmanned aircraft systems (UAS) to conduct atmospheric sampling, especially in the lower atmosphere. Instrumentation mounted on rotary- and fixed-wing aircraft are providing valuable data that offer new insights into the structure and evolution of the planetary boundary layer – a region of the atmosphere, which has been largely under-sampled. Moreover, measurements from instrumented UAS are allowing us to better understand how trace gases and particulates are distributed in the lower atmosphere. As this technology continues to mature, however, we are confronted with the question of how to best utilize weather observing UAS (WxUAS). During the summer of 2018, a large number of scientists and engineers gathered in the San Luis Valley of Colorado to participate in the Lower Atmospheric Process Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE). One objective of the one-week field campaign was to explore the impact of using UAS to study the ABL and develop strategies for sampling targeted atmospheric phenomena. In particular, LAPSE-RATE identified three meteorological science topics: convection initiation, boundary-layer transitions, and drainage flows. In addition to the WxUAS used during LAPSE-RATE, data were collected using radiosondes, ground based remote sensors, mobile mesonets, and fixed instrumented towers.

Here we present an overview of LAPSE-RATE from a University of Oklahoma (OU) perspective and summarize some of the success and challenges encountered. During the field campaign, over 1200 flights were logged by the various participating institutions, with over 200 of these from OU. We primarily operated rotary-wing aircraft with a focus on producing profiles of pressure, temperature, humidity, wind speed, and wind direction up to an altitude of 914 m (3000 ft) AGL. Flights were made every 15 – 30 minutes. LAPSE-RATE consisted of a calibration/validation phase and a data collection phase. During four of the data collection days, all participants joined to address a preselected science objective. The first two days were focused on convection initiation. One day was dedicated to boundary layer transitions and another to drainage flows. We present preliminary results from LAPSE-RATE, with the focus being on observations collected at the sites where the OU team was operating. Overall, the field campaign is considered to have been very successful.