Abstract
Advancements in remotely piloted aircraft systems (RPASs) introduced a new way to observe the atmospheric boundary layer (ABL). Adequate sampling of the lower atmosphere is key to improving numerical weather models and understanding fine-scale processes. The ABL’s sensitivity to changes in surface fluxes leads to rapid changes in thermodynamic variables. This study proposes using low-level buoyancy to characterize ABL transitions. Previously, buoyancy has been used as a bulk parameter to quantify stability. Higher-resolution data from RPASs highlight buoyancy fluctuations. RPAS profiles from two field campaigns are used to assess the evolution of buoyancy under convective and stable boundary layers. Data from these campaigns included challenging events to forecast accurately, such as convection initiation and a low-level jet. Throughout the daily ABL transition, results show that the ABL height determined by the minimum in vertical buoyancy gradient agrees well with proven ABL height metrics, such as potential temperature gradient maxima. Moreover, in the cases presented, low-level buoyancy rapidly increases prior to the convection initiation and rapidly decreases prior to the onset of a low-level jet. Low-level buoyancy is a force that is sensitive in space and time and, with further analysis, could be used as a forecasting tool. This study expounds on the utility of buoyancy in the ABL and offers potential uses for future research.
Francesca Lappin
Ph.D. Student
Dr. Tyler M. Bell
Research Scientist
Tyler is a Research Associate in CIWRO working on using ground-based remote sensors and WxUAS to advance the understanding of various boundary layer processes. He is acitvely exploring ways to optimally combine data collected from WxUAS and ground-based remote sensing.
Dr. Elizabeth A. Pillar-Little
Former Research Scientist
Elizabeth Pillar-Little was the Assistant Director for the former Center for Autonomous Sensing and Sampling at the University of Oklahoma, where she was responsible for coordinating the field deployments of RPAS teams from both an operational and scientific perspective. She also ensured the continuity of day-to-day center business and enjoyed spearheading outreach and science communication activities on behalf of the center. She was also appointed as a research scientist in the School of Meteorology and led the atmospheric chemistry research nucleus of CASS. Dr. Pillar-Little’s research interests were broadly centered around atmospheric and environmental chemistry, but she is very passionate about atmospheric composition, aerosol optical properties and composition, and the interplay between aerosols and convection initiation.