Turbulent variance characteristics of temperature and humidity over a non-uniform land surface for an agricultural ecosystem in China

Gao, Z.; Bian, L.; Chen, Z.; Sparrow, M.; Zhang, J.. 2006 Turbulent variance characteristics of temperature and humidity over a non-uniform land surface for an agricultural ecosystem in China. Advances in Atmospheric Sciences, 23 (3). 365-374. https://doi.org/10.1007/s00376-006-0365-y

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Official URL: http://www.iap.ac.cn/publ/aas/

Abstract/Summary

This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass (10% of area), beans (15%), corn (15%) and rice (60%). Under unstable conditions, the standard deviations of temperature and water vapor density (normalized by appropriate scaling parameters), observed by a single instrument, followed the Monin-Obukhov similarity theory. The similarity constants for heat (CT ) and water vapor (Cq) were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations (20% or 30% at most) of the similarity “constants” may be within the expected range of variation of a single instrument from the generally-valid relations.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1007/s00376-006-0365-y
ISSN:	0256-1530
Additional Keywords:	turbulent fluxes, eddy covariance, flux variance, non-uniform land surface
Date made live:	12 Feb 2007 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/144082

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1007/s00376-006-0365-y

ISSN:

0256-1530

Additional Keywords:

turbulent fluxes, eddy covariance, flux variance, non-uniform land surface

Date made live:

12 Feb 2007 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/144082