Connections Between Pressure Perturbations and Dynamic Flow Patterns in the Tanana Valley, Alaska

The Tanana Valley is a southeast-northwest oriented valley, located in central Alaska to the north of the Alaska Range. The valley extends over 400 km from Northway, where the valley is quite narrow, to Fairbanks where the valley widens into the Tanana flats. Its interior location allows for large diurnal temperature ranges and local thermally-driven circulations as well as dynamic channeling arising from pressure gradients originating from weather disturbances over the Pacific as well as the continent's interior. Resulting surface pressure perturbations are examined using real-time data from USArray's Transportable Array designed to monitor seismic activity. Surface pressure sensors are being deployed along with the seismic sensors across Alaska after having been deployed earlier in the continental United States. The pressure perturbations obtained from the USArray network data are examined separately within differing temporal scales, e.g., mesoscale, sub-synoptic, and synoptic scale. Since the USArray network is currently being deployed across Alaska, additional pressure and surface-based observations from other sources available from MesoWest are being used as well.

Due to the its interior location surrounded by complex terrain, the Tanana Valley is prone to strong pressure gradients, especially from Northway to Delta Junction, which is located approximately half way down the valley. These pressure gradients induce strong, dynamically driven near-surface flows that often interact with, or are enhanced by, the surrounding topography. These strong winds can result in structural damage and, during the summer, can contribute to severe convective storms that when accompanied with lightning, are a serious fire hazard. The goal of this study is to understand the connections between pressure perturbations on various scales and strong wind events in the Tanana Valley as well as the environments that support such events. Case studies that highlight Chinook winds and the Tanana Valley Jet are presented.