Valley Circulation Experiment: A Classification of Wind Flow in the H.J. Andrews Experimental Forest

Weak wind flow at night is a poorly understood phenomenon in the field of meteorology. The Valley Circulation Experiment (VALCEX) aimed at creating a wind climatology for the Lookout and McRae Valleys in H. J. Andrew (HJA). Two Sound Detection and Ranging (SoDAR) systems and two sonic anemometers were installed at two stations in adjoining valleys: Lookout Valley, near the HJA Headquarters meteorological station, called Primet, and McRae Valley, approximately 6 kilometers away. Among other variables, each station collected wind speed and direction data in 10 m vertical increments starting at 15 m to 395 m above ground level, aggregated into 5-minute mean averages. Research questions for the study include: 1) To what extent are wind speeds and directions similar at the two stations? 2) Under what conditions do the two instrument locations experience similar phenomena or connectivity? 3) Can a visual classification of sodargrams based on 5 fundamental characteristics in this case synoptic forcing, wind direction, valley jet, pulsing, and similar be used to determine connectivity between the two stations?
Results indicate that based on the 5 criteria the wind flow in the valley was considered connected between the two stations on 43 of the 96 nights classified. The two stations, McRae and Primet, were classified as weak synoptic forcing on 79 of the 96 nights classified. The second criterion, wind direction was classified almost equally at each station; 52 nights were classified as from the North-northeast while 42 nights were classified as from the Southwest. The criterion of valley jet present was determined visually on 49 of the nights.