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Wes! Elk Mine • dominant. By 8:00 p.m., the drainage flow pattern is once again well established. The wind patterns of Site 3 significantly differ from those at Sites 1 and 2. Drainage flow at Site 3 comes out of the south. [n fact, there exists a small component of the wind out of the south- southwest which opposes the major drainage flow at the lower levels. This indicates that Site 3 is above the major drainage flow at the lower levels and is simply measuring the light drainage from the higher terrain above it directly to the south. Periods of upslope flow also indicate that the terrain to the south of Site 3 dominate the winds at that site. Upslope flows aze from the north, with few exceptions. Temperature The average diurnal variations in air temperature over the spring quarter at Sites 1 and 3 are presented in Figure 13. Data from the summer quarter aze presented in Figure 14. The primary point of interest in both figures is the timing of the early moming temperature increase. During the spring, the temperature begins its daytime climb an hour earlier at Site 3 than at Site 1. The air temperature during the summer quarter at Site 3 begins its climb an hour earlier than at Site 2, which precedes the climb at Site 1 by an hour. This indicates that the cold drainage flows diminish in intensity and vanish at the upper sites first. The vertical mixing and resulting upper-level flow coupling, which brings the relatively warmer upper-level air down to the surface, begins with Site 3 and proceeds then to the level at Site 2, and finally reaches Site 1 deep within the canyon about two or three hours after sunrise. This is easily understood by realizing that the canyon and mountain sides are heated faster than the canyon floor when the sun is low, as during the early moming. Relative Humidity and Precipitation The relative humidity at Site 2 averaged 58 percent during the summer quarter. Too little data exist for the spring quarter to make a meaningful comparison. Although this value seems high, it should be remembered that the site lies within a deep mountain canyon sitting at the base of a large mountain range. The average relative humidity during the summer ranged from a 30 percent to 88 percent. The highest humidity occurred during extremely cold drainage flows. The lower average relative humidities occurred during unstable upslope flows. Overall, relative humidity ranged from five percent to 100 percent. The total accumulatedprecipitationat Site 2 for the summer period was f.60 inches. Because of the low data recovery at Site 2 during the spring, the reported accumulation of 0.17 inches is not believed to be representativeofche springtime precipitation. Air a[i • Limited sampling at the West Elk site has indicated relatively low concentrationsoftntal suspended particulate matter even with the aridity of the region. The particulate data collected over the 2.04-117 1/947805; 8/947871; 6/95 PR06