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Zhao S.-H.,Satellite Environment Center | Zhao S.-H.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Zhang F.,Satellite Environment Center | Zhang F.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | And 7 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

Hyper-spectral remote sensing (RS) technology has been widely used in environmental protection. The present work introduces its recent application in the RS monitoring of pollution gas, green-house gas, algal bloom, water quality of catch water environment, safety of drinking water sources, biodiversity, vegetation classification, soil pollution, and so on. Finally, issues such as scarce hyper-spectral satellites, the limits of data processing and information extract are related. Some proposals are also presented, including developing subsequent satellites of HJ-1 satellite with differential optical absorption spectroscopy, greenhouse gas spectroscopy and hyper-spectral imager, strengthening the study of hyper-spectral data processing and information extraction, and promoting the construction of environmental application system.


Xu H.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Xu H.,CAS Institute of Remote Sensing | Li Z.-Q.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Li Z.-Q.,CAS Institute of Remote Sensing | And 2 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2013

For standard algorithm of atmospheric correction of water, the ratio of two near-infrared (NIR) channels is selected to determine an aerosol model, and then aerosol radiation at every wavelength is accordingly estimated by extrapolation. The uncertainty of radiation measurement in NIR bands will play important part in the accuracy of water-leaving reflectance. In the present research, erroneous expressions were derived mathematically in order to see the error propagation from NIR bands. The errors distribution of water-leaving reflectance was thoroughly studied. The results show that the bigger the errors of measurement are made, the bigger the errors of water-leaving reflectance are retrieved, with sometimes the NIR band errors canceling out. Moreover, the higher the values of aerosol optical depth or the more the component of small particles in aerosol, the bigger the errors that appear during retrieval.


Zhao S.,Satellite Environmental Center | Zhao S.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Wang Q.,Satellite Environmental Center | Wang Q.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | And 5 more authors.
Journal of Agricultural Science and Technology | Year: 2016

Water content plays an important role in the process of plant photosynthesis and biomass accumulation. Many methods have been developed to retrieve canopy leaf water content from remote sensing data. However, the validity of these methods has not been verified, which limits their applications. This study estimates the Leaf Water Content (LWC) of winter wheat with three most widely used indexes: Normalized Difference Water Index (NDWI), Simple Ratio (SR), and Shortwave Infrared Perpendicular Water Stress Index (SPSI), as well as MODIS short wave and near infrared data, and then compares remote sensing estimates of vegetation water content with field-measured values measured in concurrent dates. The results indicate that the three indexes are significantly correlated with the LWC of winter wheat at the 0.01 significance level. They all have good accuracy with higher than 90%. The indexes derived from MODIS bands 6 and 2 were better than those from bands 7 and 2 for measuring wheat leaf water content, and the correlations of the former two (NDWI and SR) were stronger than that of SPSI. © 2016, Tarbiat Modares University. All Rights reserved.


Zhu L.,Environment Satellite Center | Zhu L.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Zhao L.-M.,CAS Institute of Remote Sensing | Wang Q.,Environment Satellite Center | And 8 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014

Thermal plume from coastal nuclear power plant is a small-scale human activity, mornitoring of which requires high-frequency and high-spatial remote sensing data. The infrared scanner (IRS), on board of HJ-1B, has an infrared channel IRS4 with 300 m and 4-days as its spatial and temporal resolution. Remote sensing data aquired using IRS4 is an available source for mornitoring thermal plume. Retrieval pattern for coastal sea surface temperature (SST) was built to monitor the thermal plume from nuclear power plant. The research area is located near Guangdong Daya Bay Nuclear Power Station (GNPS), where synchronized validations were also implemented. The National Centers for Environmental Prediction (NCEP) data was interpolated spatially and temporally. The interpolated data as well as surface weather conditions were subsequently employed into radiative transfer model for the atmospheric correction of IRS4 thermal image. A look-up-table (LUT) was built for the inversion between IRS4 channel radiance and radiometric temperature, and a fitted function was also built from the LUT data for the same purpose. The SST was finally retrieved based on those preprocessing procedures mentioned above. The bulk temperature (BT) of 84 samples distributed near GNPS was shipboard collected synchronically using salinity-temperature-deepness (CTD) instruments. The discrete sample data was surface interpolated and compared with the satellite retrieved SST. Results show that the average BT over the study area is 0.47℃ higher than the retrieved skin temperature (ST). For areas far away from outfall, the ST is higher than BT, with differences less than 1.0℃. The main driving force for temperature variations in these regions is solar radiation. For areas near outfall, on the contrary, the retrieved ST is lower than BT, and greater differences between the two (meaning >1.0℃) happen when it gets closer to the outfall. Unlike the former case, the convective heat transfer resulting from the thermal plume is the primary reason leading to the temperature variations. Temperature rising (TR) distributions obtained from remote sensing data and in-situ measurements are consistent, except that the interpolated BT shows more level details (>5 levels) than that of the ST (up to 4 levels). The areas with higher TR levels (>2) are larger on BT maps, while for lower TR levels (≤2), the two methods perform with no obvious differences. Minimal errors for satellite-derived SST occur regularly around local time 10 a.m. This makes the remote sensing results to be substitutes for in-situ measurements. Therefore, for operational applications of HJ-1B IRS4, remote sensing technique can be a practical approach to monitoring the nuclear plant thermal pollution around this time period.


Zhao S.,Satellite Environment Center | Zhao S.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Zhang C.,Shandong Agricultural University | Xiong Y.,Sun Yat Sen University | And 5 more authors.
Journal of the Indian Society of Remote Sensing | Year: 2016

A new model was developed to monitor bare surface soil moisture on regional scale from the semi-empirical scattering model (Oh et al. 2002). This study carried out the field experiments almost simultaneously with the satellite overpass to validate the model. The results indicate that the model-estimated soil moisture agrees well with the measurements. This model requires no ground priori information and depends only on two radar images with dual co-polarization of hh-vv at different incidence angles. Because the model assumes that the soil characteristics (e.g. soil moisture and roughness) are constant, it is crucial that the two temporal images should be acquired on the same day or closely-spaced dates with no events of precipitation or irrigation and no occurrence of significant human activities. © 2016 Indian Society of Remote Sensing


Ma P.-F.,CAS Institute of Remote Sensing | Ma P.-F.,Environmental Satellite Application Center | Ma P.-F.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Chen L.-F.,CAS Institute of Remote Sensing | And 9 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

Nitrous Oxide is a very important greenhouse gases and ozone-depleting substances. Due to the limited observations, there are still many uncertainties to quantitativelydescribe therole of nitrous oxide played in both cases. We can retrieve the methane and carbon dioxide gas using thermal infrared satellite data AIRS, but it is rarely for the nitrous oxide retrieval. Therefore, this paper retrieves nitrous oxideprofiles from the AIRS data with anOptimal Estimate Method for the first time in China. The issue of the a priori and channelselection is discussed. Comparison of the retrieved AIRS profiles with HIPPOprofiles show the retrieved profiles are in good agreement with the smoothed HIPPO profiles, and a notable improvementin this algorithmthan the eigenvector regression algorithm. For pressures between 300 and 900 hPa, we got the most accurate profiles and the relative erroris only 0.1%, which is consistent with the jacobian peaks of the selected channels. ©, 2015, Science Press. All right reserved.


Xu H.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Xu H.,CAS Institute of Remote Sensing | Xu H.,University of Chinese Academy of Sciences | Gu X.-F.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | And 7 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2011

Atmospheric correction is a bottleneck in quantitative application of Chinese satellites HJ-1 data to remote sensing of water color. According to the characteristics of CCD sensors, the present paper made use of air-water coupled radiative transfer model to work out the look-up table (LUT) of atmospheric corrected parameters, and thereafter developed pixel-by-pixel atmospheric correction method over waters accomplishing the water-leaving remote sensing reflectance with accessorial meteorological input. The paper validates the HJ-1 CCD retrievals with MODIS and in-situ results. It was found that the accuracy in blue and green bands is good. However, the accuracy in red or NIR bands is much worse than blue or green ones. It was also demonstrated that the aerosol model is a sensitive factor to the atmospheric correction accuracy.


Yin S.-J.,Satellite Environment Center | Yin S.-J.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | Wu C.-Q.,Satellite Environment Center | Wu C.-Q.,State Environmental Protection Key Laboratory of Satellite Remote Sensing | And 5 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2016

This study introduces landscape structure indices into the ecological assessment system of riparian health, taking advantage of remote sensing capabilities in the derivation of riparian zone, feature extraction of ecological structure, and high-precision classification of ecological system. An overall ecological investigation and assessment of riparian health along Huaihe River was carried out from the aspects of ecological function, ecosystem structure and ecological stress. The results showed that the health of riparian ecology along Huaihe River was generally poor, with an ecological health index less than 0.3. A significant spatial characteristic was shown that the ecological environment gradually became worse from upstream to midstream and then slightly improved. Intensive human development, low vegetation coverage, low natural shoreline rate and high human disturbance were identified as the main cause of the bad ecological condition of the riparian zone along Huaihe River, according to the analysis of ecological and environmental problems. © 2016, Chinese Society for Environmental Sciences. All right reserved.


PubMed | State Environmental Protection Key Laboratory of Satellite Remote Sensing
Type: Journal Article | Journal: Guang pu xue yu guang pu fen xi = Guang pu | Year: 2013

For standard algorithm of atmospheric correction of water, the ratio of two near-infrared (NIR) channels is selected to determine an aerosol model, and then aerosol radiation at every wavelength is accordingly estimated by extrapolation. The uncertainty of radiation measurement in NIR bands will play important part in the accuracy of water-leaving reflectance. In the present research, erroneous expressions were derived mathematically in order to see the error propagation from NIR bands. The errors distribution of water-leaving reflectance was thoroughly studied. The results show that the bigger the errors of measurement are made, the bigger the errors of water-leaving reflectance are retrieved, with sometimes the NIR band errors canceling out. Moreover, the higher the values of aerosol optical depth or the more the component of small particles in aerosol, the bigger the errors that appear during retrieval.


PubMed | State Environmental Protection Key Laboratory of Satellite Remote Sensing
Type: Journal Article | Journal: Guang pu xue yu guang pu fen xi = Guang pu | Year: 2012

Atmospheric correction is a bottleneck in quantitative application of Chinese satellites HJ-1 data to remote sensing of water color. According to the characteristics of CCD sensors, the present paper made use of air-water coupled radiative transfer model to work out the look-up table (LUT) of atmospheric corrected parameters, and thereafter developed pixel-by-pixel atmospheric correction method over waters accomplishing the water-leaving remote sensing reflectance with accessorial meteorological input. The paper validates the HJ-1 CCD retrievals with MODIS and in-situ results. It was found that the accuracy in blue and green bands is good. However, the accuracy in red or NIR bands is much worse than blue or green ones. It was also demonstrated that the aerosol model is a sensitive factor to the atmospheric correction accuracy.

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