DOI: 10.5194/hess-18-1885-2014
Scopus记录号: 2-s2.0-84901253939
论文题名: Upscaling of evapotranspiration fluxes from instantaneous to daytime scales for thermal remote sensing applications
作者: Cammalleri C ; , Anderson M ; C ; , Kustas W ; P
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2014
卷: 18, 期: 5 起始页码: 1885
结束页码: 1894
语种: 英语
Scopus关键词: Budget control
; Errors
; Remote sensing
; Solar radiation
; Sun
; Uncertainty analysis
; Actual evapotranspiration
; Eddy covariance data
; Eddy covariance technique
; Evaporative fraction
; Scaling methodology
; Seasonal dependence
; Statistical evaluation
; Thermal remote sensing
; Evapotranspiration
; eddy covariance
; energy budget
; evapotranspiration
; land cover
; sampling
; solar radiation
; summer
; upscaling
英文摘要: Four upscaling methods for estimating daytime actual evapotranspiration (ET) from single time-of-day snapshots, as commonly retrieved using remote sensing, were compared. These methods assume self-preservation of the ratio between ET and a given reference variable over the daytime hours. The analysis was performed using eddy covariance data collected at 12 AmeriFlux towers, sampling a fairly wide range in climatic and land cover conditions. The choice of energy budget closure method significantly impacted performance using different scaling methodologies. Therefore, a statistical evaluation approach was adopted to better account for the inherent uncertainty in ET fluxes using eddy covariance technique. Overall, this approach suggested that at-surface solar radiation was the most robust reference variable amongst those tested, due to high accuracy of upscaled fluxes and absence of systematic biases. Top-of-atmosphere irradiance was also tested and proved to be reliable under near clear-sky conditions, but tended to overestimate the observed daytime ET during cloudy days. Use of reference ET as a scaling flux yielded higher bias than the solar radiation method, although resulting errors showed similar lack of seasonal dependence. Finally, the commonly used evaporative fraction method yielded satisfactory results only in summer months, July and August, and tended to underestimate the observations in the fall/winter seasons from November to January at the flux sites studied. In general, the proposed methodology clearly showed the added value of an intercomparison of different upscaling methods under scenarios that account for the uncertainty in eddy covariance flux measurements due to closure errors. © 2014 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78237
Appears in Collections: 气候变化事实与影响
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作者单位: US Department of Agriculture, Agricultural Research Service, Hydrology and Remote Sensing Laboratory, Beltsville, MD, United States; European Commission, Joint Research Centre, 21027 Ispra (VA), Italy
Recommended Citation:
Cammalleri C,, Anderson M,C,et al. Upscaling of evapotranspiration fluxes from instantaneous to daytime scales for thermal remote sensing applications[J]. Hydrology and Earth System Sciences,2014-01-01,18(5)