OVERCOLLECTION OF SOLID PRECIPITATION
BY A STANDARD PRECIPITATION GAGE,
NIWOT RIDGE, COLORADO

Tim Bardsley and Mark W. Williams

Institute of Arctic and Alpine Research and
Department of Geography, CB 450,
University of Colorado, Boulder, CO


Figure 3.
A comparison of annual precipitation totals from 1987 through 1996 show that the average precipitation amount of 1854 mm measured at the saddle site was 54% greater than the 1200 mm measured at D1. A pooled t-test shows that this difference was significant at the alpha = 0.05 level (p = 0.002, n = 10). Furthermore, the standard deviation of annual precipitation at the saddle of 580 mm was about twice that of the 206 mm at D1. We hypothesize that the higher standard deviation at the saddle site may be caused by blowing snow. Wind speed, available snow, and surface hardness are the three main variables controlling snow redistribution and are highly variable with time.