A note on the roughness length for temperature over melting snow and ice

Abstract The characteristics of roughness length for temperature, zT , over melting snow and ice are examined on the base of data gathered during one summer season on the Greenland ice sheet. Despite fixed surface temperature and homogeneous surface conditions, zT is highly variable, taking on value...

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Bibliographic Details
Published in:Quarterly Journal of the Royal Meteorological Society
Main Author: Calanca, Pierluigi
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2001
Subjects:
Online Access:http://dx.doi.org/10.1002/qj.49712757114
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fqj.49712757114
https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49712757114
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Summary:Abstract The characteristics of roughness length for temperature, zT , over melting snow and ice are examined on the base of data gathered during one summer season on the Greenland ice sheet. Despite fixed surface temperature and homogeneous surface conditions, zT is highly variable, taking on values between 10 −5 and 1 m. Mean value and median are computed as 2 × 10 −2 m and 1 × 10 −3 m. It thus turns out that zT is about 10 to 100 times larger than the aerodynamic roughness length, z 0. This disparity cannot be explained in terms of the roughness Reynolds number. Rather, the data show that over melting snow and ice, and for slightly stable conditions, zT is uniquely determined by the temperature defect.