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Hongwei X.,University of Chinese Academy of Sciences | Hongwei X.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | Hongwei X.,Beijing Normal University | Rui S.,University of Chinese Academy of Sciences | And 5 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2012

ET plays an important role in the energy exchange mass transfer between the hydrosphere, atmosphere and biosphere. ET is a critical variable in hydrological modeling and provides important boundary conditions for weather prediction. Environment and Disasters Monitoring Microsatellite Constellation of A and B star (HJ-1A/B), which was developed by China, has high space and temporary resolution and is widely used. In this paper, SEBS model and Priestley-Taylor Equation combined with Ts-NDVI feature space are used to estimate ET of Heihe River basin. The remote sensing data including visible and infrared data are acquired by HJ-1A/B satellites. We use GLDAS ET product as validation data. By comparison, the results show that HJ-1A/B data can be effectively used to estimate ET. © 2012 IEEE.


Qiao C.,Beijing Normal University | Qiao C.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | Sun R.,Beijing Normal University | Sun R.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | And 5 more authors.
IEEE Geoscience and Remote Sensing Letters | Year: 2015

The transpiration from shelterbelts and the evapotranspiration (ET) from cropland (maize and vegetables) and orchards (apple) in an irrigated area in the middle reaches of the Heihe River, China, were estimated using a modified Penman-Monteith (P-M) formula and airborne remote sensing data. The results were compared to the shelter transpiration results obtained from measurements of sup flow in tree trunks made with thermal dissipation probes and the latent heat fluxes observed by the eddy covariance technique at flux towers in croplands. The modified P-M formula was found to be an effective means to estimate not only the cropland and orchard ET but also the shelter transpiration. The seasonal variation of shelterbelt transpiration was smaller than those of cropland and orchard ET. Estimates of ET made using the P-M formula along with the remote sensing data showed that 9.9%, 3.1%, and 87.0% of the total ET were allotted to shelterbelts, apple orchards, and cropland, respectively. © 2004-2012 IEEE.


Zhu Z.,Beijing Normal University | Zhu Z.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | Tan L.,Beijing Normal University | Tan L.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | And 4 more authors.
IEEE Geoscience and Remote Sensing Letters | Year: 2014

The newly developed cosmic-ray probe (CRP) method for measuring area-average soil moisture at the hectometer horizontal scale was tested in the 2012 observation campaign of the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) in the irrigated cropland area of Zhangye Oasis. As compared with the traditional point observation, data analysis shows that the CRP could measure the real areal soil moisture, except when the water is frozen and during thaw. During the irrigation period, the presence of surface water can lead to an overestimation of the soil moisture. During non-irrigated periods, the CRP has a very strong correlation with the averaged soil moisture of 19 SoilNET probes in its footprint, whose R2is 0.73 and root-mean-square error is 0.0275 m3/m3. In comparison with the Polarimetric L-band Multi-beam Radiometer (PLMR) retrieved soil moisture, which has a pixel resolution of 700 m, the CRP provides much better results, with a coefficient of determination of 0.96 and 0.64, respectively. The results show that the CRP is a robust area-averaged soil moisture observation method, which can be used to obtain 'true' values of field-scale soil moisture for remote sensing validation. © 2014 IEEE.


Feng L.,Beijing Normal University | Feng L.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | Sun R.,Beijing Normal University | Sun R.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | And 5 more authors.
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2011

Carbon cycle of terrestrial ecosystem is one of the hot issues in global change science. And there are more difficult during study with agroecosystem because of the strong affect caused by human activities such as sowing, fertilizing and irrigation. In this study, a measurement is carried out in Guantao, Hebei Province, China, which is a typical argoecosystem station. In this paper, carbon dioxide fluxes in Guantao, were simulated by BIOME-BGC model as well, and the result was compared with the eddy covariance (EC) data. The result shows that the trend curves of simulated data and observation data were well matched in growing season of winter wheat in 2009. © 2011 IEEE.


Li Y.,Beijing Normal University | Li Y.,Beijing Key Laboratory of Environmental Remote Sensing and City Digitalization | Li Y.,Monash University | Sun R.,Beijing Normal University | And 3 more authors.
Science China Earth Sciences | Year: 2015

Land surface process modeling of high and cold area with vegetation cover has not yielded satisfactory results in previous applications. In this study, land surface energy budget is simulated using a land surface model for the A’rou meadow in the upper-reach area of the Heihe River Basin in the eastern Tibetan Plateau. The model performance is evaluated using the in-situ observations and remotely sensed data. Sensible and soil heat fluxes are overestimated while latent heat flux is underestimated when the default parameter setting is used. By analyzing physical and physiological processes and the sensitivities of key parameters, the inappropriate default setting of optimum growth and inhibition temperatures is identified as an important reason for the bias. The average daytime temperature during the period of fastest vegetation growth (June and July) is adopted as the optimum growth temperature, and the inhibition temperatures were adjusted using the same increment as the optimum temperature based on the temperature acclimation. These adjustments significantly reduced the biases in sensible, latent, and soil heat fluxes. © 2014, Science China Press and Springer-Verlag Berlin Heidelberg.

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