Publication Date

Spring 2023

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Meteorology and Climate Science

Advisor

Craig Clements

Subject Areas

Meteorology

Abstract

Wildfires in complex terrain have resulted in tragic loss and have highlighted the vulnerability of communities over the past several years. The added intensity created by downslope windstorms, and the lack of high temporal and spatial resolution of ground observations motivates the ongoing need to understand and increase predictability of Sundowners. Sundowners, downslope windstorms that are typically intensified around sunset, are a common and significant weather phenomenon observed along the Santa Barbara coastline and are known to increase challenges during wildfire events. The Sundowner Winds EXperiment (SWEX) was a six-week field campaign from 01 April to 15 May 2022 in Santa Barbara County, California. The campaign utilized ground and air operations to study the dynamics of sundowner winds by increasing spatial and temporal measurements by acquiring thermodynamic and kinematic variables. This thesis focuses on two Intensive Operational Periods (IOP): IOP2 measuring from 5-6 April and IOP6 measuring from 28-29 April. Each period is analyzed using a ground-based LiDAR instrument, radiosondes, dropsondes, and several Integrated Surface Flux System stations. Both events observed strong mountain wave activity and strong surface winds. At the end of the period, observed by several ISFS stations and the LiDAR, there was a rapid onset of weak, southeast winds in response to the onset of the marine boundary layer (MBL). This manuscript focuses on the analysis of observations during sundowner winds, mountain wave activity, and the impact of the MBL.

Download

Share

COinS