Publication Date:
2016-11-29
Description:
Uncertainty in ground heat flux (G) means that evaluation of the other terms in the surface energy balance (e.g., latent and sensible heat flux, LE and H ) remains problematic. Algorithms that calculate LE and H require available energy, the difference between net radiation, R NET , and G. There are a wide range of approaches to model G for large-scale applications, with a subsequent wide range of estimates and accuracies. We provide the largest review of these methods to date (N = 6), evaluating modeled G against measured G from 88 FLUXNET sites. The instantaneous mid-day variability in G is best captured by models forced with net radiation, while models forced by temperature show the least error at both instantaneous and daily timescales. We produce global decadal datasets of G to illustrate regional and seasonal sensitivities, as well as uncertainty. Global model mean mid-morning instantaneous G is highest during September, October, and November at 63.42 (+/- 16.84) Wm -2 while over December, January, and February G is lowest at 53.86 (+/- 18.09) Wm -2 but shows greater inter-model uncertainty. Results from this work have the potential to improve ET estimates and guide appropriate G model selection and development for various land uses.
Print ISSN:
0148-0227
Topics:
Biology
,
Geosciences
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