DOI: 10.1002/2013JD020813
论文题名: A simple model for spatial disaggregation of evaporative fraction: Comparative study with thermal sharpened land surface temperature data over India
作者: Eswar R. ; Sekhar M. ; Bhattacharya B.K.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 21 起始页码: 12029
结束页码: 12044
语种: 英语
英文关键词: Agro-Met Stations
; evaporative fraction
; spatial disaggregation
; thermal sharpening
Scopus关键词: Radiometers
; Range finding
; Satellite imagery
; Bowen ratio energy balances
; Enhanced thematic mappers
; Evaporative fraction
; Micrometeorological towers
; Moderate resolution imaging spectroradiometer
; Normalized difference vegetation index
; Spatial disaggregation
; thermal sharpening
; Atmospheric temperature
; Aqua (satellite)
; Bowen ratio
; clear sky
; comparative study
; evaporation
; land cover
; land surface
; Landsat thematic mapper
; latent heat flux
; micrometeorology
; MODIS
; surface temperature
; Terra (satellite)
; India
英文摘要: Evaporative fraction (EF) is a measure of the amount of available energy at the earth surface that is partitioned into latent heat flux. The currently operational thermal sensors like the Moderate Resolution Imaging Spectroradiometer (MODIS) on satellite platforms provide data only at 1000 m, which constraints the spatial resolution of EF estimates. A simple model (disaggregation of evaporative fraction (DEFrac)) based on the observed relationship between EF and the normalized difference vegetation index is proposed to spatially disaggregate EF. The DEFrac model was tested with EF estimated from the triangle method using 113 clear sky data sets from the MODIS sensor aboard Terra and Aqua satellites. Validation was done using the data at four micrometeorological tower sites across varied agro-climatic zones possessing different land cover conditions in India using Bowen ratio energy balance method. The root-mean-square error (RMSE) of EF estimated at 1000 m resolution using the triangle method was 0.09 for all the four sites put together. The RMSE of DEFrac disaggregated EF was 0.09 for 250 m resolution. Two models of input disaggregation were also tried with thermal data sharpened using two thermal sharpening models DisTrad and TsHARP. The RMSE of disaggregated EF was 0.14 for both the input disaggregation models for 250 m resolution. Moreover, spatial analysis of disaggregation was performed using Landsat-7 (Enhanced Thematic Mapper) ETM + data over four grids in India for contrasted seasons. It was observed that the DEFrac model performed better than the input disaggregation models under cropped conditions while they were marginally similar under non-cropped conditions. Key Points A simple model for spatial Disaggregation of Evaporative Fraction is proposed. Utility of sharpened land surface temperature for estimation of EF is tested. The proposed model performed well in four sites in India. ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63182
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Civil Engineering and Indo-French Cell for Water Sciences, Indian Institute of Science, Bangalore-560012, Karnataka, India; Space Applications Centre, Indian Space Research Organisation, Ahmedabad, India
Recommended Citation:
Eswar R.,Sekhar M.,Bhattacharya B.K.. A simple model for spatial disaggregation of evaporative fraction: Comparative study with thermal sharpened land surface temperature data over India[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(21)