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A Multifactor Weighting Method for Improved Clear View Compositing Using All Available Landsat 8 and Sentinel 2 Images in Google Earth Engine

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Journal of Remote Sensing

Journal of remote sensing 2023年第1期3卷 343-361页

作者： Shili Meng Yong Pang Chengquan Huang Zengyuan Li Institute of Forest resource Information Techniques Chinese Academy of ForestryBeijing 100091China Key Laboratory of Forestry remote sensing and Information System National Forestry and Grassland AdministrationBeijing 100091China department of Geographical Sciences University of MarylandCollege ParkMD 20742USA

The increasing availability of freely accessible remote sensing data has been crucial for improved global monitoring *** image combination is a common approach for overcoming a major limitation associated with single-sensor data sources,which cannot provide adequate observations to fill data gaps arising from cloud contamination,shadows,and other atmospheric *** particular,image compositing is often used to generate clear view images over a large *** example,the best available pixel(BAP)method has been proposed to construct clear view and spatially contiguous composites based on pixellevel quality *** any location with a bad observation,this method searches observations acquired in other dates and uses the one with the highest score to replace the contaminated ***,however,can lead to artificially large discontinuities along the edge of a filled area,which is typically caused by large phenological differences among the observations *** mitigate this issue,we developed a multifactor weighting(MFW)method for constructing clear view composites with a higher level of spatial continuity and radiometric consistency than those produced using the BAP *** over 4 study sites selected from different climate zones in China demonstrated that the composites produced using the MFW method were more consistent with reference images than those generated using the BAP *** agreements between MFW composites and the reference(R=0.78 to 0.95)were generally higher than the agreements between BAP composites and the reference(R=0.65 to 0.93).These results demonstrated that the proposed MFW method can provide a promising strategy for constructing clear view,seamless,and radiometrically consistent image composites for large-scale applications.

关键词： composites constructing Engine

Stable classi?cation with limited sample: transferring a 30-m resolution sample set collected in 2015 to mapping 10-m resolution global land cover in 2017

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Science Bulletin 2019年第6期64卷 370-373页

作者： Peng Gong Han Liu Meinan Zhang Congcong Li Jie Wang Huabing Huang Nicholas Clinton Luyan Ji Wenyu Li Yuqi Bai Bin Chen Bing Xu Zhiliang Zhu Cui Yuan Hoi Ping Suen Jing Guo Nan Xu Weijia Li Yuanyuan Zhao Jun Yang Chaoqing Yu Xi Wang Haohuan Fu Le Yu Iryna Dronova Fengming Hui Xiao Cheng Xueli Shi Fengjin Xiao Qiufeng Liu Lianchun Song Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System Science Tsinghua University AI for Earth Lab Cross-Strait Institute Tsinghua University department of Environmental Science Policy and Management University of CaliforniaBerkeley State Key Laboratory of remote sensing Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Google LLC Institute of Electronics Chinese Academy of Sciences United States Geological Survey National Supercomputing Center in Wuxi department of Landscape Architecture University of CaliforniaBerkeley State Key Laboratory of remote sensing Science College of Global Change and Earth System Science Beijing Normal University National Climate Center China Meteorological Administration

As the world strives to reduce the impact of population growth, urbanization, agricultural expansion, and climate change on food security, energy and water shortage, resource over-exploration, biodiversity loss, environmental pollution, and ultimately human health, timely and higher resolution land cover information is urgently needed to achieve the sustainable development goals of the United Nations.

关键词： the world strives to reduce timely and higher resolution information is urgently needed

A quantitative performance comparison of paddy rice acreage estimation using stratified sampling strategies with different stratification indicators

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International Journal of Digital Earth 2018年第10期11卷 1001-1019页

作者： Peijun Sun Jinshui Zhang Russell G.Congalton Yaozhong Pan Xiufang Zhu State Key Laboratory of Earth Surface Processes and resource Ecology Beijing Normal UniversityBeijingPeople’s Republic of China Institute of remote sensing and Engineering Faculty of Geographical ScienceBeijing Normal UniversityBeijingPeople’s Republic of China department of Natural resources and the Environment University of New HampshireDurhamNHUSA

Various indicators derived from thematic maps have been widely used to determine the strata needed to perform stratified ***,these indicators typically do not quantify the spatial errors in the crop thematic maps that are needed to reduce the *** address this lack of error information,this paper introduces a hybrid entropy indicator(HEI).Two conventional indicators,the acreage indicator(AI)and the fragmentation indicator(FI),were also evaluated to compare the results of the three indicators in a homogeneous agricultural area(Pinghu,PH)and a heterogeneous agricultural area(Zhuji,ZJ).The results show that HEI performs the best in heterogeneous areas with the lowest coefficient of variation(CV)(as low as 1.59%)and also has the highest estimation accuracy with the lowest standard deviation of *** both areas,the performances of HEI and AI are very similar,and better than *** results highlight that the HEI should be considered as an effective indicator and used in place of AI and FI to help improve sampling efficiency of crop acreage estimation,while FI is not ***,the positive performance achieved using HEI indicates the potential for incorporating thematic map uncertainty information to improve sampling efficiency.

关键词： Acreage estimation stratification sampling hybrid entropy indicator acreage indicator fragmentation indicator

Characterization of Forest Degradation beyond Canopy Cover Change in Mau Forest, Kenya

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Open Journal of Forestry 2022年第4期12卷 393-407页

作者： Merceline Awuor Ojwala Felix Mutua Mwangi James Kinyanjui department of Geomatic Engineering and Geospatial Information Systems Jommo Kenyatta University of Agriculture and Technology Nairobi Kenya Directorate of resource surveys and remote sensing Nairobi Kenya School of Natural resources and Environmental Studies Karatina University Karatina Kenya

Monitoring Forest degradation is evidence enough to show a country’s commitment to monitor the forest trend both for national and local decision-making and international reporting processes. Unlike deforestation which is easier to point out, monitoring forest degradation is quite a challenge since there is no universal definition and thus no clear monitoring methods apart from the canopy cover change. This research, therefore, sought to look at the degradation trends in the Mau forest complex between 1995-2020 with the aim of finding out whether monitoring canopy density changes over time and quantifying these changes in terms of biomass loss could be a good approach in monitoring forest degradation. Forest Canopy Density (FCD) model was adopted focusing on using vegetation indices describing biophysical conditions of Vegetation, Shadow and Bareness to monitor changes in canopy density as a parameter for describing forest degradation in the forest blocks of Maasai Mau and Olpusimoru in Mau forest complex. Results indicated how different vegetation indices responded to changes in the vegetation density and eventually changes in the canopy density values which were converted in terms of biomass loss. The forest Canopy Density model proved to be a good tool for monitoring forest degradation since it combines different biophysical indices with different characteristics capturing what is happening below the canopy.

关键词： Forest Degradation Canopy Density Vegetation Indices Biomass Loss Monitoring

Downward continuation of aeromagnetic data to the marine surface

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Acta Oceanologica Sinica 2008年第1期27卷 54-60页

作者： XU Shizhe WANG Rui ZHOU Jianxin XIAO Pengfei CHEN Shengchang department of Earth Sciences Zhejiang University Hangzhou 310027 China department of Navigation Guarantee Navy Headquarters Chinese People＇s Libration Army Tianjing 300042 China China Aero-geophysieal Survey and remote sensing Center for Land and Natural resource Beijing 100083 China School of Geophysics and Information Technology China University of Geosciences Beijing 100083 China

The existing methods of downward continuation of potential field cannot be used to continue the aeromagnetic data to the marine surface because of the limited continuation distance. An iteration method for the downward continuation of potential field with a much larger continuation distance has been developed, which can continue the aeromagnetic data to the marine surface and get the marine - magnetic chart with the same scale as the aeromagnetic data. This downward continuation method will greatly raise the ef- ficiency of marine - magnetic investigation. The principle of the iteration method is presented. The method is demonstrated on synthetic models and real aeromagnetic data. Also, the error brought by continuation is discussed. The efficiency of the iteration method for the downward continuation of potential field is compared with the fast fourier transform （FFT） method, the former is much better than the latter.

关键词： aeromagnetic marine-magnetic downward continuation of potential field iteration method fast fourier transform

Quantitative Estimation of Groundwater Leakage from Namco Lake by SAR Monitoring

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1555-1556页

作者： CHEN Jiaqi DENG Yunkai LI Ning WANG Yu LIU Zhongling ZHANG Shilin Computer and Information College Hohai University Nanjing 210098 Jiangsu China department of Space Microwave remote sensing System Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

Objective This study focused on the Namco, the largest lake on the Tibet plateau as well as the highest large lake in the world. A large imbalance between water input and output of this lake has attracted great attention in the field of hydrogeology during recent years. As there is no surface outflow from Namco, the large water imbalance can only be explained by water seepage. Synthetic aperture radar （SAR） image data were used for the first time in combination with hydrological data actually measured in the field and meteorological station data, to quantitatively acquire the information of surface fluctuation, water storage variation, and to estimate groundwater leakage from Namco Lake. The results provide theoretical support and data for further understanding the processes and extent of water resource response to global climate change, and also provide a scientific basis for rational development and utilization of water resource in the Tibetan Plateau.

关键词： Lake Quantitative Estimation of Groundwater Leakage from Namco Lake by SAR Monitoring SAR

Assessment of the three factors affecting Myanmar’s forest cover change using Landsat and MODIS vegetation continuous fields data

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International Journal of Digital Earth 2016年第6期9卷 562-585页

作者： Fu-Jiang Liu Chengquan Huang Yong Pang Mengxue Li Dan-Xia Song Xiao-Peng Song Saurabh Channan Joseph O.Sexton Die Jiang Ping Zhang Yan Guo Yao-Feng Li John R.Townshend department of remote sensing Science and Technology China University of GeosciencesWuhan CityPeople’s Republic of China department of Geographical Sciences University of MarylandCollege ParkMDUSA Institute of Forest resource Information Technique Chinese Academy of ForestryBeijingPeople’s Republic of China department of Computer Science and Technology China University of GeosciencesWuhan CityPeople’s Republic of China

Long-term observation of the earth is essential for studying the factors affecting global environmental *** earth technology can facilitate the monitoring of global environmental change with its ability to process vast amounts of *** this study,we map the forest cover change of Myanmar from 2000 to 2005 using a training data automation procedure and support vector machines *** results show that Myanmar’s forests have declined 0.68%annually over this six-year *** validated our derived change results and found the overall accuracy to be greater than 88%.We also assessed forest loss from protected areas,areas close to roads,and areas subject to fire,which were most likely to lose forested *** results revealed the main reasons for forest losses in some hotspots to be increased agricultural conversion,fire,and the construction of *** information is useful for identifying the driving forces behind forest changes and to support environmental policy development in Myanmar.

关键词： Forest cover change deforestation Landsat protected area roads Myanmar

Leaf pigment retrieval using the PROSAIL model: Influence of uncertainty in prior canopy-structure information

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The Crop Journal 2022年第5期10卷 1251-1263页

作者： Jia Sun Lunche Wang Shuo Shi Zhenhai Li Jian Yang Wei Gong Shaoqiang Wang Torbern Tagesson Key Laboratory of Regional Ecology and Environmental Change School of Geography and Information EngineeringChina University of GeoscienceWuhan 430079HubeiChina department of Physical Geography and Ecosystem Science Lund UniversityLund 117 SE-22100Sweden State Key Laboratory of Information Engineering in Surveying Mappingand Remote SensingWuhan UniversityWuhan 430079HubeiChina Key Laboratory of Quantitative remote sensing in Ministry of Agriculture and Rural Affairs Beijing Research Center for Information Technology in AgricultureBeijing 100097China department of Geosciences and Natural resource Management University of CopenhagenCopenhagen 1172Denmark

Leaf pigments are critical indicators of plant photosynthesis,stress,and physiological *** of radiative transfer models(RTMs)is a promising method for robustly retrieving leaf biochem-ical traits from canopy observations,and adding prior information has been effective in alleviating the“ill-posed”problem,a major challenge in model *** structure parameters,such as leaf area index(LAI)and average leaf inclination angle(ALA),can serve as prior information for leaf pigment *** canopy spectra simulated from the PROSAIL model,we estimated the effects of uncertainty in LAI and ALA used as prior information for lookup table-based inversions of leaf chlorophyll(C _(ab))and car-otenoid(C_(ar)).The retrieval accuracies of the two pigments were increased by use of the priors of LAI(RMSE of C_(ab) from 7.67 to 6.32μg cm^(-2),C_(ar) from 2.41 to 2.28μg cm^(-2))and ALA(RMSE of C_(ab) from 7.67 to 5.72μg cm^(-2),C_(ar) from 2.41 to 2.23μg cm^(-2)).However,this improvement deteriorated with an increase of additive and multiplicative uncertainties,and when 40% and 20% noise was added to LAI and ALA respectively,these priors ceased to increase retrieval *** using an experimental winter wheat dataset also showed that compared with C_(ar),the estimation accuracy of C_(ab) increased more or deteriorated less with uncertainty in prior canopy *** study demonstrates possible limita-tions of using prior information in RTM inversions for retrieval of leaf biochemistry,when large uncer-tainties are present.

关键词： Leaf pigment PROSAIL model Canopy structure Chlorophyll content Leaf area index Leaf angle distribution

Country-scale spatio-temporal monitoring of soil erosion in Iran using the G2 model

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International Journal of Digital Earth 2021年第8期14卷 1019-1039页

作者： Shahin Mohammadi Fatemeh Balouei Khadijeh Haji Abdulvahed Khaledi Darvishan Christos G.Karydas department of remote sensing and GIS Faculty of Earth SciencesShahid Chamran University of AhvazAhvazIran department of Range and Watershed Management Faculty of Natural ResourcesIsfahan University of TechnologyIsfahanIran department of Watershed Management Engineering Faculty of Natural ResourcesTarbiat Modares UniversityNoorIran dremote sensing Engineer EpanomiGreece

The aim of this study was the spatial and temporal monitoring of soil erosion patterns in *** G2 model was used,as an appropriate tool to provide the required month-time step country-wide soil loss maps and statistical *** input parameters were derived with field surveys and remote sensing imagery(MODIS,SRTM,SPOT,and Sentinel-2 scenes).An innovation for G2 was the consideration of the snow cover effect on the rainfall *** was also the first time G2 was used to map such a big country like Iran on a country *** mean annual soil erosion in Iran was found to be 16.5 t ha−1,which is equal to about 2.7 billion tons of soil *** spatial terms,the highest soil loss values were found in the north,west and southwest part of Iran,in the steep slopes in Alborz and Zagros *** temporal terms,the highest and lowest monthly erosion values of 3.2 and 0.09 t ha−1 correspond to January and July,respectively.

关键词： Digital earth Land degradation Sediment yield Sentinel-2 Snow cover effect