Cold Air Drainage

Spatial variation in snowmelt processes owing to topographic effects is complicated by air temperature inversions that may be an important factor in determining the timing and rate of snowmelt. This process is of great interest in mountainous regions where snowmelt is one of the largest surface water inputs controlling runoff. Localized temperature inversions, coupled with topographic shading of solar radiation and windspeed reductions can produce ablation patterns that proceed from ridgetops to valley bottoms in some catchments. To develop a better understanding of this process, 38 temperature data loggers were installed in transect spanning three second-order catchments in the Mica Creek Experimental Watershed (MCEW) in northern Idaho. Results have thus far shown that the classic assumption of normal lapse prevailing in mountainous catchments can be incorrect. The violation of the standard assumption that air temperature decreases with altitude holds important implications for development of distributed climate surfaces to drive distributed snowmelt models.

Primary Contacts: Jason Hubbart (web page), Tim Link (web page)