https://dx.doi.org/10.1016/S0022-1694(98)00195-4">
 

Title

Momentum roughness and view-angle dependent heat roughness at a Southern Great Plains test-site

Abstract

Surface roughness parameters were determined for harvested wheat fields over level terrain at the US Department of Energy's Cloud and Radiation Testbed (CART) site in north-central Oklahoma. Measurements of wind speed and temperature were made by radiosondes and instruments mounted on 2 and 10 m towers during neutral and unstable atmospheric conditions in the atmospheric surface layer. Surface temperatures were measured radiatively over 750 m trajectories. Roughness heights were calculated for the region using the Monin–Obukhov similarity theory. The scalar roughness and the local momentum roughness were determined using wind speed measurements at 10 m and temperature measurements at 2 m combined with eddy correlation measurements for . The scalar roughness zoh was determined to be 0.0021 and 0.0038 m for the nadir and the off-nadir viewing angle, respectively. It was estimated that the displacement height d is negligible. A regional momentum surface roughness of zo=0.15 m was determined by means of the radiosonde profiles. Good agreement (r=0.92) between measured and calculated sensible heat flux values was found using an independent data set of radiosonde profiles.

Department

Earth Systems Research Center

Publication Date

11-1-1998

Journal Title

Journal of Hydrology

Publisher

Elsevier

Digital Object Identifier (DOI)

https://dx.doi.org/10.1016/S0022-1694(98)00195-4

Document Type

Article

Rights

© 1998 Elsevier Science B.V. All rights reserved.

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