Assessing the Utility of Low-Level Buoyancy and CopterSonde Measurements to Understand Atmospheric Boundary Layer Transitions

Lappin, Francesca

Assessing the Utility of Low-Level Buoyancy and CopterSonde Measurements to Understand Atmospheric Boundary Layer Transitions

dc.contributor.advisor	Klein, Petra
dc.contributor.author	Lappin, Francesca
dc.contributor.committeeMember	Yussouf, Nusrat
dc.contributor.committeeMember	Salesky, Scott
dc.date.accessioned	2021-12-08T15:22:24Z
dc.date.available	2021-12-08T15:22:24Z
dc.date.issued	2021-12-17
dc.date.manuscript	2021-12-01
dc.description.abstract	Advancements in remotely piloted aircraft systems (RPAS) 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 in convective and stable boundary layers. Data from these campaigns included challenging events to forecast accurately, such as convective initiation, a low-level jet, and katabatic flows. Results show that the ABL depth (ABLD) determined by the minimum in vertical buoyancy gradient agrees well with proven ABLD metrics, such as potential temperature gradient maxima. Moreover, in the cases presented, low-level buoyancy rapidly increases prior to convective initiation and rapidly decreases prior to the onset of a low-level jet. This study expounds on the utility of buoyancy in the ABL and contextualizes its use in comparison to Richardson number profiles. Additionally, RPAS profiles are reviewed as an operational way to aid the forecasting of aviation weather. The concept of operations is described. Based on conversations with partners in the aviation community, a visualization of the RPAS data was designed to deliver the most desirable information. Restrictions on field campaigns caused by the COVID19 pandemic impeded the goal of regular profiling at a nearby airport. Nevertheless, a handful of scenarios are assessed from the perspective of a pilot. Finally, a discussion is provided on the complications of flying an RPAS at an active airport.	en_US
dc.identifier.uri	https://hdl.handle.net/11244/331418
dc.language	en_US	en_US
dc.subject	boundary layer	en_US
dc.subject	WxUAS	en_US
dc.subject	buoyancy	en_US
dc.thesis.degree	Master of Science in Meteorology	en_US
dc.title	Assessing the Utility of Low-Level Buoyancy and CopterSonde Measurements to Understand Atmospheric Boundary Layer Transitions	en_US
ou.group	College of Atmospheric and Geographic Sciences::School of Meteorology	en_US