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Li B.,Chinese Academy of Sciences | Su H.,CAS Institute of Geographical Sciences and Natural Resources Research | Chen F.,Chinese Academy of Sciences | Wu J.,Beijing Normal University | Qi J.,Center for Land and Resources
Natural Hazards | Year: 2013

Drought is one of the most detrimental natural disasters. Studying the changing characteristics of drought is obviously of great importance to achieve the sustainable use of water resources at river basin scales. In this paper, the satellite-based Vegetation Condition Index (VCI) and Vegetation Health Index (VH) were firstly calculated by using NDVI and brightness of the Global Vegetation Index dataset derived from Advance Very High Resolution Radiometer for China in growing seasons over 1982-2005. Then, the long-term VCI and VH data were employed to study the variation of droughts in the ten basins covering the whole country. The linear trend of each pixel showed that most parts of China were getting wetter in growing seasons, and the drought areas defined by the number of drought pixels have decreased in most basins. The increasing trend of basin averaged values of VCI and VH also indicates the whole country was generally getting wetter. At last, to better understand the two remote sensing drought indices, the response of the growing-season VCI and VH was compared to that of the Palmer Drought Severity Index and 6-month Standard Precipitation Index. Significant spatial variability of the relationship between the VCI, VH, and the station-based meteorological drought indices was shown, and some more closely related areas were found. The study will be useful for water resources management for each basin in the future. © 2013 Springer Science+Business Media Dordrecht.

Liu X.-Y.,Jilin University | Fang H.-B.,Center for Land and Resources
2nd International Conference on Information Science and Engineering, ICISE2010 - Proceedings | Year: 2010

Through analysis of the copper mineralization characteristics in the area of Rigaze region in Tibet, using the weights of evidence method on Rigaze copper mineralization vision to predict areas, establish the copper deposit prospecting model, and extraction of various types and mineralization related to the formation, structure, intrusive rocks, aeromagnetic, geochemical for 14 evidence factor layers. using GIS spatial analysis function, it generated in the study area forming the posterior probability map, which can divided copper deposits vision mineralization areas into A, B two grades by the posteriori probability value. Finally in order to further ore-prospecting laid solid foundation. delineation of the three A-level areas and five B-level areas, for future research to lay a solid foundation for further exploration. © 2010 IEEE.

Zhao H.L.,Center for Land and Resources | Fan J.H.,Center for Land and Resources | Wang R.Y.,China University of Geosciences | Liu G.,CAS Institute of Remote Sensing
IET Conference Publications | Year: 2015

It is quite difficult for the scientists to carry out the field scientific research on mountain glaciers, due to the special geographical position and formidable natural conditions. In addition, the conventional measurement methods are not able to meet the requirements of the rapid monitoring and quantitative evaluation for the glacier changes. As an advanced technique for spatial information acquisition, SAR (Synthetic Aperture Radar) can monitor the ground surface motion with high precision under all weather. The unique advantages indicate that SAR is the optimum method for glacier monitoring. Considering the baseline length, temporal baseline and the continuity, three COSMO images were selected to carry out the study of the glacier flow velocity in the Tianshan Mountains using Offset-Tracking technology. From the result, we can see the displacement of the range direction of Tianshan glacier is relatively obvious while compared to the displacement of the azimuth direction. The velocity of the glacier displacement reduces from glacier axis to both sides, and increases from its origin to snowline and then reduces towards the end.

Zhang W.,Center for Land and Resources | Fan D.,China University of Mining and Technology | Yang J.,Center for Land and Resources
Proceedings - 2010 International Forum on Information Technology and Applications, IFITA 2010 | Year: 2010

This paper introduced the principle of Kalman filtering and modeling methods, however, there existed some problems with the standard Kalman filtering. Combined with the characteristics of GPS deformation monitoring data, this paper improved the algorithm of the standard Kalman filtering and proposed the Adaptive Kalman filtering method. The authors took the data of GPS deformation monitoring as an example, carried out AKF method in the VB platform, and compared the treatment results with the original data. The results show that the AKF can effectively suppress the phenomenon of divergence emerged filtering with the systematic statistical properties of real-time dynamic estimation and make the results more stable and reasonable. The results show that the Adaptive Kalman Filter proposed in this paper is more effective than the traditional methods. © 2010 IEEE.

Chen H.,Center for Land and Resources | Chen H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhuang D.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
2012 1st International Conference on Agro-Geoinformatics, Agro-Geoinformatics 2012 | Year: 2012

Net primary production (NPP) is an important parameter for the global carbon cycle research, and the remote sensing methods to estimate of it are widely concerned. In this paper, we proposed a modified CASA model to estimate NPP. Firstly, we used a new method to estimate solar radiation based on the relationship between sunset angle and sunshine hour, and then the distribution of solar radiation needed for the regional NPP calculation was acquired. Secondly, we utilized the local parameters of maximum light use efficiency 0.51gC/MJ for winter wheat and 0.66gC/MJ for summer maize specifically. Thirdly, a new water limitation factor based on LSWI (The Land Surface Water Index), which can reflect the irrigation effects, was used. Lastly, a FPAR retrieval strategy based on searching table for MODIS replaced the former CASA method. Using the common meteorological data, 8-day MODIS reflection data (MOD 09) and the distribution map of winter wheat and summer maize at Huang-Huai-Hai plain, the NPP map was acquired using the above parameterized and optimized CASA model. The yearly NPP of winter wheat is 6.028·1013gC, and that of summer maize is 4.132·1013gC at this region. The trend at time and space is clear. Double apex distribution of NPP at temporal scale is shown, the spatial distribution of winter wheat NPP is obviously related with latitude (r0.640). The value of NPP is related with climate. Winter wheat NPP is related with temperature (r0.637) and rainfall (r0.446), but summer maize NPP is most affected by solar radiation (r0.662) and sunshine (r0.614). In the different subregions of the research area, the highest winter wheat NPP (1098.89 gC/m 2a) and summer maize NPP(805.20gC/m2a) both appear in eastern Shandong district, but the lowest average NPP at subregion level is in the coastal area for winter wheat (216.62gC/m2a) and in northern Jiangsu plain for summer maize (482.10gC/m2a). © 2012 IEEE.

Chen H.,Center for Land and Resources | Chen H.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Zhuang D.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
2012 1st International Conference on Agro-Geoinformatics, Agro-Geoinformatics 2012 | Year: 2012

Crop plantation map is a fundamental data in the research and production of agriculture. Remote sensing is a fast, economic and irreplaceable tool in this research and application area. By the analysis of the penology of winter wheat and summer maize using the data from agro-meteorological station and the characteristics analysis of the 8-day time-series MODIS NDVI of winter wheat and summer maize, this paper proposed a model to extract the distribution of winter wheat and summer maize based on NDVI apex and valley characters. The threshold of winter wheat at county level in the model was derived with the density cutting method using the agricultural statistical data of planting area and MODIS NDVI data. The relationship between threshold and latitude was proposed, which reflects the controlling role of latitude to temperature and crop growth. Then, the threshold of winter wheat at the pixel level was estimated using the above-mentioned relationship. Using this threshold, we get the distribution of winter wheat. The accuracy evaluation using 90 stations showed that the overall areal resolution is about 91.15% and the accuracy at county scale is averaged as 67.52%. The distribution of summer maize was extracted using the threshold at county level. The distribution map demonstrated that the coverage of winter wheat and summer maize were affected by the growing condition at local region. Most of them appeared at plain, but less of them distributed at the region with bad condition such as rugged and salt-affected seaside area. In the yanshan and taihangshan mountainous area, the land surface is rugged with high slope, thin soil and poor irrigation condition. So, the amount of crops is limited in this area. Otherwise, in the plain area before the mountain area and the lower plain the winter wheat and summer maize were widely planted with percentage more than 60%. Lastly, in the coastal area near bohai gulf which was affected by salt, the crops were rare in distribution. © 2012 IEEE.

Kun S.,Center for Land and Resources | Xiao C.,Center for Land and Resources | Wei H.,Center for Land and Resources | Xie Y.,CAS Institute of Remote Sensing
4th International Workshop on Earth Observation and Remote Sensing Applications, EORSA 2016 - Proceedings | Year: 2016

In the present stage, there are a large amount of classification methods for hyperspectral remote sensing data. It has always been a crucial problem that how to select a suitable classifier because these methods may have different application scopes. Based on Pushbroom Hyperspectral Imager (PHI) data that includes 80 spectral bands and covers 8 vegetation classes, this study performed a serious classification experiments to test the characteristics of some popular classifiers (Maximum Likelihood, Spectral Angle Mapper, Decision Tree Classifier and Support Vector Machine) with different training sampling numbers and dimensions of feature bands. According to the classification results, this paper analyses the application of different classifiers on the sophisticated vegetation classification with hyperspectral data. © 2016 IEEE.

Li W.,Center for Land and Resources | Zhou J.,Center for Land and Resources | Xiong S.,Center for Land and Resources | Liu Y.,Center for Land and Resources | Xu J.,Center for Land and Resources
Acta Geologica Sinica | Year: 2013

This paper takes the South Yellow Sea as an example to show a new method for comprehensive geological-geophysical research such as residual basin and tectonolayering using airborne gravity and magnetic data in China. Based on airborne gravity and magnetic data, by measuring and analyzing stratigraphic density and susceptibility, the depths to the pre-Sinian magnetic basement top, the pre-Jurassic top and the Cenozoic bottom, are obtained by forward and inverse methods constrained by seismic and drilling data; and furthermore, the residual thicknesses of the Sinian-Triassic, the Jurassic-Cretaceous and the Cenozoic are calculated. Based on airborne gravity and magnetic anomalies, the faults in the pre-Sinian magnetic basement, the Jurassic- Cretaceous and the Cenozoic are respectively interpreted by the qualitative and quantitative methods. On the basis of the above study, and combining regional important tectonic events, four tectonolayers are divided in the vertical succession in South Yellow Sea, namely the pre-Sinian magnetic basement, the Sinian-Triassic, the Jurassic-Cretaceous and the Cenozoic. The result shows that there are thick Cenozoic and Jurassic-Cretaceous strata and thin residual Sinian-Triassic strata in the Suzhong- Huangnan depression area, but there are thin or only sporadic Mesozoic-Cenozoic terrestrial strata and thick Sinian-Triassic marine strata reserved in Subei-Huangzhong uplift area and Sunan- Wunansha uplift area. The four tectonolayers are very different in structures as well as distributions in plane.

Fan J.,Center for Land and Resources | Tu P.,China Three Gorges University | Guo X.,Center for Land and Resources | Wang Y.,Center for Land and Resources | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

In order to monitor the surface deformation of Shuping landslide in the Yangtze River Three Gorges area, the method of differential SAR interferometry (DInSAR) using corner reflectors (CR) was applied. 12 CR, including 10 pyramidal corner reflectors (PCR) and 2 asymmetrical cubic corner reflectors (ACCR), were designed, made, and deployed on Shuping landslide. Based on the numerical test and the preliminary analyses of 5 ENVISAT ASAR images, we concluded that: 1) ACCR can provide strong response signal even without the best SAR look angle and is especially fit for the multi-angle applications of DInSAR; 2) given a simple phase model, the least square (LS) method can be used to analyze the CR's differential phase and get the accumulative deformation value.© 2010 SPIE.

Li W.,Center for Land and Resources | Zhou J.,Center for Land and Resources | Liu Y.,Center for Land and Resources | Xu J.,Center for Land and Resources
Exploration Geophysics | Year: 2015

An airborne gravity survey was successfully conducted over the Dongying, Gudao and Gudong oilfields of Shengli oil province, eastern China. These survey areas cover onshore and offshore regions of the south-west Bohai Sea. The data were processed using the potential field transformation approach. The derived Bouguer gravity data correlate well with features such as known faults, swells and sags identified by earlier seismic survey and drilling data. The depth to the Cenozoic basement in the study area, including the Dongying, Gudao, and Gudong oilfields, was calculated by means of gravity inversion constrained by seismic and drilling data. The differences between the depths to the Cenozoic basement calculated from gravity anomaly and those determined by the earlier seismic and drilling data are less than 5%. © ASEG 2015.

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