National Oceanic and
Atmospheric Administration
United States Department of Commerce


 

FY 1983

Regional wind patterns of the inland waters of western Washington and southern British Columbia

Schoenberg, S.A.

NOAA Tech. Memo. ERL PMEL-43, NTIS: PB83-207969, 61 pp (1983)


This study generalizes a time series of regional wind fields in an area of strong topographic influence. Wind speed and direction measured by 6 meteorological buoys and l tower anemometer were used in addition to routinely available surface observations. The data were measured during the last three weeks of February and the first week of March in 1980 when the region's upper-level flow was dominated by a quasi-stationary ridge, which broke down midway and again in the last 5 days of the period to allow passage of small-amplitude troughs. The 850-mb wind direction measured at Quillayute, Washington, was chosen as an indicator of synoptic-scale flow uninfluenced by the topography. The directions measured at 12-hour intervals were divided into 11 classes of 30° each. The corresponding surface wind fields were then grouped, and the resultant vector and persistence fields were mapped for each class. The 11 wind field composites showed that while the wind field varied in a regular fashion as the synoptic-scale flow varied, Bernoulli-type down-pressure-gradient flow in restricted channels and geostrophy both operated as balancing mechanisms to the imposed synoptic-pressure gradient in different areas simultaneously. As the 850-mb wind became parallel to the Strait of Georgia and Puget Sound, 140°–190°, and then shifted to the west, the surface wind fields abruptly shifted from primarily an east-west orientation to a north-south orientation. In the absence of a pressure gradient between Port Hardy, B.C., and Portland, Oregon, of greater than 3 mb, a diurnal wind circulation was observed in the eastern Strait of Juan de Fuca, the southern Strait of Georgia, and Puget Sound.




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