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Zhigang Sun Qinxue Wang Bunkei Matsushita Takehiko Fukushima Zhu Ouyang Masataka Watanabe 《水文科学杂志》2013,58(5):994-1012
Abstract A simple remote sensing evapotranspiration (ET) model (Sim-ReSET) has been proposed but only tested using field measurements at a site with a semi-arid climate. Its performance for mapping ET using only satellite data remained unknown. In this study, the Sim-ReSET model was further evaluated for ET estimation driven by only MODIS data products. The estimated ET rates were compared with ground-based observational data from a variety of ecosystems and climates across China. The results show that MODIS-based ET estimates are consistent with both the ET measurements from eddy covariance flux towers and those from the Penman-Monteith method combined with micrometeorological data. Evaporation fraction (EF) is indicative of land surface moisture. The derivative EF maps demonstrate that the proposed ET data set obtained from the Sim-ReSET model and MODIS data is capable of capturing the spatio-temporal pattern of land surface moisture for different land covers with different climates. Editor Z.W. Kundzewicz Citation Sun, Z.G., Wang, Q.X., Matsushita, B., Fukushima, T., Ouyang, Z., Watanabe, M., and Gebremichael, M., 2013. Further evaluation of the Sim-ReSET model for ET estimation driven by only satellite inputs. Hydrological Sciences Journal, 58 (5), 994–1012. 相似文献
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Youichi Oyama Bunkei Matsushita Takehiko Fukushima Kazuo Matsushige Akio Imai 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(1):73-85
The remote sensing of Case 2 water has been far less successful than that of Case 1 water, due mainly to the complex interactions among optically active substances (e.g., phytoplankton, suspended sediments, colored dissolved organic matter, and water) in the former. To address this problem, we developed a spectral decomposition algorithm (SDA), based on a spectral linear mixture modeling approach. Through a tank experiment, we found that the SDA-based models were superior to conventional empirical models (e.g. using single band, band ratio, or arithmetic calculation of band) for accurate estimates of water quality parameters. In this paper, we develop a method for applying the SDA to Landsat-5 TM data on Lake Kasumigaura, a eutrophic lake in Japan characterized by high concentrations of suspended sediment, for mapping chlorophyll-a (Chl-a) and non-phytoplankton suspended sediment (NPSS) distributions. The results show that the SDA-based estimation model can be obtained by a tank experiment. Moreover, by combining this estimation model with satellite-SRSs (standard reflectance spectra: i.e., spectral end-members) derived from bio-optical modeling, we can directly apply the model to a satellite image. The same SDA-based estimation model for Chl-a concentration was applied to two Landsat-5 TM images, one acquired in April 1994 and the other in February 2006. The average Chl-a estimation error between the two was 9.9%, a result that indicates the potential robustness of the SDA-based estimation model. The average estimation error of NPSS concentration from the 2006 Landsat-5 TM image was 15.9%. The key point for successfully applying the SDA-based estimation model to satellite data is the method used to obtain a suitable satellite-SRS for each end-member. 相似文献
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广域空间尺度上植被净初级生产力的精确推算 总被引：11，自引：0，他引：11
作者介绍了使用遥感、GIS数据和BEPS生态过程模型推算植被净初级生产力 (NPP)的方法。为了准确推算北海道地区NPP,我们改进了BEPS模型,而且使用了高质量GIS数据作为模型的输入数据。通过计算得出1998年北海道NPP的平均值为644 g C/m2,总量为0.078 Gt C。我们还进行了模型输入数据质量对应用生态过程模型推算NPP的精度影响测试。结果表明,高质量的GIS输入数据可以提高NPP推算精度16.6%~39.7%。 相似文献
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Fan Yang Bunkei Matsushita Takehiko Fukushima 《ISPRS Journal of Photogrammetry and Remote Sensing》2010,65(5):479-490
The impervious surface area (ISA) has emerged not only as an indicator of the degree of urbanization, but also as a major indicator of environmental quality for drainage basin management. However, since almost all of the methods for estimating ISA have been developed for urban environments, it is questionable whether these methods can be successfully applied to drainage basins, such as those found in Japan, which usually have more complicated vegetation components (e.g. paddy field, plowed field and dense forest). This paper presents a pre-screened and normalized multiple endmember spectral mixture analysis (PNMESMA) method, which includes a new endmember selection strategy and an integration of the normalized spectral mixture analysis (NSMA) and multiple endmember spectral mixture analysis (MESMA), for estimating the ISA fraction in Lake Kasumigaura Basin, Japan. This new proposed method is superior to the previous methods in that the estimation error of the proposed method is much smaller than the previous SMA- or NSMA-based methods for drainage basin environments. The overall root mean square error was reduced to 5.2%, and no obvious underestimation or overestimation occurred for high or low ISA areas. Through the assessment of environmental quality in Lake Kasumigaura Basin using the ISA fraction, the results showed that the basin has been in the impacted category since 1987, and that in the two decades since, the environmental quality has continued to decline. If this decline continues, then Lake Kasumigaura Basin will fall into the degraded category by 2017. 相似文献
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吸收系数和后向散射系数是水体的固有光学特性参数,在探测水体中各组分浓度的过程中起着至关重要的作用.但通常组分固有光学特性的测定是一个操作复杂且费时费力的过程.提出了一种利用已知组分浓度和相应的反射光谱的水体样本来推定水体中各组分的吸收和后向散射系数的算法,并利用生物光学模型产生的模拟光谱数据对算法的合理性进行了验证.结果表明,在理想的实验条件下(反射光谱满足机理模型,且选取的训练样本相互独立),可以高精度地反演出各组分的固有光学特性,从而证实了本算法在理论卜的合理性. 相似文献
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