Geometric versus anemometric surface roughness for a shallow accumulating snowpack

Geosciences
By: , and 

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Abstract

When applied to a snow-covered surface, aerodynamic roughness length, z0, is typically considered as a static parameter within energy balance equations. However, field observations show that z0 changes spatially and temporally, and thus z0 incorporated as a dynamic parameter may greatly improve models. To evaluate methods for characterizing snow surface roughness, we compared concurrent estimates of z0 based on (1) terrestrial light detection and ranging derived surface geometry of the snowpack surface (geometric, z0G) and (2) vertical wind profile measurements (anemometric, z0A). The value of z0Gwas computed from Lettau’s equation and underestimated z0A but compared well when scaled by a factor of 2.34. The Counihan method for computing z0G was found to be unsuitable for estimating z0 on a snow surface. During snowpack accumulation in early winter, z0 varied as a function of the snow-covered area (SCA). Our results show that as the SCA increases, z0 decreases, indicating there is a topographic influence on this relation.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Geometric versus anemometric surface roughness for a shallow accumulating snowpack
Series title Geosciences
DOI 10.3390/geosciences8120463
Volume 12
Issue 8
Year Published 2018
Language English
Publisher MDPI
Contributing office(s) Colorado Water Science Center
Description Article 463; 10 p.
First page 1
Last page 10