BUOY OBSERVATIONS OF THE ATMOSPHERE ALONG THE WEST-COAST OF THE UNITED-STATES, 1981-1990

The distribution of statistical properties of the meteorological and s ea surface temperature fields along the west coast of the United State s is described based on 10-yearlong observations from buoys deployed b y the National Data Buoy Center. The observations suggest that propert ies vary differently in each of three different regions along the coas t: the Southern California Eight which remains sheltered from strong w ind forcing throughout the year; the central and northern California c oast up to Cape Mendocino, the site of persistent equatorward winds; a nd the Oregon-Washington coast, where traveling cyclones and anticyclo nes produce vigorous and variable forcing. Over most of the region the variance in the wind speed is roughly equally divided between the ann ual cycle and the synoptic forcing, corresponding to periods between 5 and 50 cycles per year. Two seasons, summer and winter, are sufficien t to describe the annual cycle. During the summer, two distinct wind s peed maxima occur along the coast, one near Point Conception and the o ther off northern California, between Point Reyes and Point Arena. In the winter a single maximum occurs, located near Point Conception. The atmospheric pressure generally increases with latitude along the coas t, but the annual cycle of atmospheric pressure has a different phase, depending on location; off the coast of California, highest pressures are found during the winter, while off Oregon and Washington, the hig hest pressures occur during the summer. Fluctuations in air and sea te mperature are highly correlated, and the sea temperature is usually hi gher than the air temperature, in the winter. Examination of vertical soundings of the atmosphere at Oakland, Vandenberg Air Force Base and San Diego during the same period of time reveals that a well-defined i nversion separates the marine boundary layer (MBL) from the free atmos phere above nearly 90% of the time during the summer and half the time during the winter. Station soundings consistently overestimate the MB L thickness, but the results do suggest that the MBL is supercritical part of the time in the vicinity of the three sites. An attempt is mad e to examine the interannual variability and compare it to the Souther n Oscillation index, although the results are limited because the reco rd length is short compared with interannual timescales. Spatially ave raged temperature anomalies increase during winter 1982-1983, coincide nt with the large El Nino event.