作者机构：
[O'Connell, Jessica; Tao, Jianbin; Cotten, David L.; Mishra, Deepak R.] Univ Georgia, Dept Geog, Athens, GA 30609 USA.;[Tao, Jianbin] Cent China Normal Univ, Coll Urban & Environm Sci, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan 430079, Hubei, Peoples R China.;[Pahari, Roshani; Leclerc, Monique; Zhang, Gengsheng; Nahrawi, Hafsah Binti] Univ Georgia, Atmospher Biogeosci Grp, Griffin, GA 30223 USA.;[Nahrawi, Hafsah Binti] Univ Malaysia Sarawak, Fac Resource Sci & Technol, Kota Samarahan 94300, Malaysia.
通讯机构：
[Mishra, Deepak R.] U;Univ Georgia, Dept Geog, Athens, GA 30609 USA.
关键词：
MODIS GPP Calibration;MOD17A2;Normalized Distribution Moisture Index;Tide Adjusted Wetland Index;flux GPP;salt marsh;tidal wetlands
摘要：
Despite the importance of tidal ecosystems in the global carbon budget, the relationships between environmental drivers and carbon dynamics in these wetlands remain poorly understood. This limited understanding results from the challenges associated with in situ flux studies and their correlation with satellite imagery which can be affected by periodic tidal flooding. Carbon dioxide eddy covariance (EC) towers are installed in only a few wetlands worldwide, and the longest eddy-covariance record from Georgia (GA) wetlands contains only two continuous years of observations. The goals of the present study were to evaluate the performance of existing MODIS Gross Primary Production (GPP) products (MOD17A2) against EC derived GPP and develop a tide-robust Normalized Difference Moisture Index (NDMI) based model to predict GPP within a Spartina alterniflora salt marsh on Sapelo Island, GA. These EC tower-based observations represent a basis to associate CO2 fluxes with canopy reflectance and thus provide the means to use satellite-based reflectance data for broader scale investigations. We demonstrate that Light Use Efficiency (LUE)-based MOD17A2 does not accurately reflect tidal wetland GPP compared to a simple empirical vegetation index-based model where tidal influence was accounted for. The NDMI-based GPP model was capable of predicting changes in wetland CO2 fluxes and explained 46% of the variation in flux-estimated GPP within the training data, and a root mean square error of 6.96 g C m−2 in the validation data. Our investigation is the first to create a MODIS-based wetland GPP estimation procedure that demonstrates the importance of filtering tidal observations from satellite surface reflectance data.
作者机构：
[Wang, Dong; Xu, Xiao-Dong] Cent China Normal Univ, Sch Life Sci, Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei, Peoples R China.
通讯机构：
[Wang, Dong] C;Cent China Normal Univ, Sch Life Sci, Key Lab Geog Proc Anal & Simulat, Wuhan 430079, Hubei, Peoples R China.
摘要：
Hylomecon japonica (Papaveraceae) is the sole species of its genus. Two varieties, H. japonica var. dissecta and H. japonica var. subincisa, have been recognized, but the presence of numerous morphological intermediates renders the intraspecific taxa controversial. Based on observations of natural populations and molecular sequences of nDNA (NADPH) and cpDNA (rpoB-trnC and trnG intron regions), our results show that the samples identified as distinct varieties are scattered and nested within the subclades of plants identified as H. japonica var. japonica. As a whole, all samples of H. japonica are monophyletic; this is further supported by the continuous variation in leaf morphology. As a result, the two infraspecific names are synonymized with H. japonica. Our study emphasizes the importance of evaluating the full range of morphological variation and molecular data when describing infraspecific taxa within a morphologically variable species.
期刊：
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS,2017年14(11):2082-2086 ISSN：1545-598X
通讯作者：
Peng, Feifei
作者机构：
[Luo, Jing; Peng, Feifei] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Coll Urban & Environm Sci, Wuhan 430079, Hubei, Peoples R China.;[Wang, Gaoqiang] Huzhou Inst Surveying & Mapping, Huzhou 313000, Peoples R China.;[Qi, Kunlun] China Univ Geosci, Fac Informat Engn, Wuhan 430074, Hubei, Peoples R China.
通讯机构：
[Peng, Feifei] C;Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Coll Urban & Environm Sci, Wuhan 430079, Hubei, Peoples R China.
关键词：
Digital surface model (DSM);image retrieval;orthoimage;stereo image;visual word;visual word pair
摘要：
The wide availability of high-resolution satellite stereo images has created a surging demand for effective stereo image retrieval methods. Recently, few retrieval methods have been designed specifically for stereo images having unique characteristics (e.g., viewing number and viewing angles), and often have insufficient retrieval accuracy. A new content-based stereo image retrieval method is achieved with height and planar visual word pairs, which are generated from the stereo extracted digital surface models and orthoimages. Experimental results of the International Society for Photogrammetry and Remote Sensing stereo benchmark test data set show that our method outperforms the state-of-the-art methods in terms of accuracy and stability. Our method achieves a high retrieval precision of 0.9, and has a high efficiency. Our method is stable for two stereo pairs, covering the same scene from different sensors, which usually have a small ranking difference in the returned ranking list. Our method is helpful to quickly and accurately locate desired stereo images from large quantities of multisensor stereo images.
摘要：
Quantitative information regarding the long-term variability of precipitation and vegetation during the period covering both the Late Glacial and the Holocene on the Qinghai-Tibetan Plateau (QTP) is scarce. Herein, we provide new and numerical reconstructions for annual mean precipitation (PANN) and vegetation history over the last 18,000 years using high-resolution pollen data from Lakes Dalianhai and Qinghai on the northeastern QTP. Hitherto, five calibration techniques including weighted averaging, weighted average-partial least squares regression, modern analogue technique, locally weighted weighted averaging regression, and maximum likelihood were first employed to construct robust inference models and to produce reliable PANN estimates on the QTP. The biomization method was applied for reconstructing the vegetation dynamics. The study area was dominated by steppe and characterized with a highly variable, relatively dry climate at ~18,000–11,000 cal years B.P. PANN increased since the early Holocene, obtained a maximum at ~8000–3000 cal years B.P. with coniferous-temperate mixed forest as the dominant biome, and thereafter declined to present. The PANN reconstructions are broadly consistent with other proxy-based paleoclimatic records from the northeastern QTP and the northern region of monsoonal China. The possible mechanisms behind the precipitation changes may be tentatively attributed to the internal feedback processes of higher latitude (e.g., North Atlantic) and lower latitude (e.g., subtropical monsoon) competing climatic regimes, which are primarily modulated by solar energy output as the external driving force. These findings may provide important insights into understanding the future Asian precipitation dynamics under the projected global warming.
摘要：
In this paper, a stochastic equilibrium chance-constrained programming (SECCP) model was developed for tackling the municipal waste management issue under uncertainty. The main advantage of this model is that it effectively reflected the dual-random characteristics of uncertain parameters through incorporating the opinions and judgments from various respondents into the parameter identification processes. This will lead to birandom variables, where their mean values and standard deviations are allowed to be the random variables, instead of the fixed values. The generation of birandom variables will enrich the stochastic optimization theory and improve the accuracy and rationality of parameters design and estimation. The equilibrium chance-constrained programming algorithm was used to solve the SECCP model, which is capable of tackling birandom variables and is overcoming limitations of traditional stochastic chance-constrained programming while parameters with normal distribution are required strictly. Currently, the application of SECCP model in the environmental management fields was limited. As the first attempt, the regional waste management of the City of Dalian, China, was used as a study case for demonstration. A variety of solutions are beneficial in providing decision space to the local managers through designing and adjusting the constraints-violation levels. This solution process also reflected trade-off between system economy and reliability. The successful application in regional waste management system is expected to be a good example for tackling other similar problems.
期刊：
International Journal of Geographical Information Science,2017年31(6):1079-1100 ISSN：1365-8816
通讯作者：
Yu, Wenhao
作者机构：
[Yu, Wenhao] China Univ Geosci, Fac Informat Engn, Wuhan, Peoples R China.;[Yu, Wenhao] Tianjin Univ, Sch Marine Sci & Technol, Tianjin, Peoples R China.;[Ai, Tinghua] Wuhan Univ, Sch Resource & Environm Sci, Wuhan, Peoples R China.;[Liu, Pengcheng] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan, Peoples R China.;[Cheng, Xiaoqiang] Hubei Univ, Fac Resources & Environm Sci, Wuhan, Peoples R China.
通讯机构：
[Yu, Wenhao] C;[Yu, Wenhao] T;China Univ Geosci, Fac Informat Engn, Wuhan, Peoples R China.;Tianjin Univ, Sch Marine Sci & Technol, Tianjin, Peoples R China.
关键词：
Building pattern;spatial cognition;texture analysis;texton co-occurrence matrix
摘要：
The representation and analysis of building patterns are critical for characterizing urban scenes and making decisions in urban planning. The evaluation of building patterns is a difficult spatial analysis problem that exhibits properties of symbolization, homogeneity and regularity. Open issues in this field include the development of approaches for representing building patterns and vector-based methods for computing various pattern metrics. In the image analysis domain, there are many methods for pattern recognition e.g., texture analysis, but there are few corresponding solutions for vector data. The aim of this research is to develop several building pattern metrics and offer a texton co-occurrence matrix TCM-based method to quantitatively evaluate the features of building patterns. The procedure first constructs a spatial field based on a Delaunay triangulation skeleton to partition a set of buildings into a set of tessellation cells. The tessellations of building clusters have a similar structure as image representations, in that each cell corresponds to an image pixel. We then use the texton analysis to establish a matrix to describe the tessellation structure, including the neighboring relationships and individual attribute information. Finally, a set of feature descriptors is obtained from the TCM to capture the texture-related information of building groups. Through experiments on building pattern analysis and spatial queries, we show that the results of TCM-based evaluation of building patterns are consistent with those of human cognition. The representation and analysis of building patterns are critical for characterizing urban scenes and making decisions in urban planning. The evaluation of building patterns is a difficult spatial analysis problem that exhibits properties of symbolization, homogeneity and regularity. Open issues in this field include the development of approaches for representing building patterns and vector-based methods for computing various pattern metrics. In the image analysis domain, there are many methods for pattern recognition e.g., texture analysis, but there are few corresponding solutions for vector data. The aim of this research is to develop several building pattern metrics and offer a texton co-occurrence matrix TCM-based method to quantitatively evaluate the features of building patterns. The procedure first constructs a spatial field based on a Delaunay triangulation skeleton to partition a set of buildings into a set of tessellation cells. The tessellations of building clusters have a similar structure as image representations, in that each cell corresponds to an image pixel. We then use the texton analysis to establish a matrix to describe the tessellation structure, including the neighboring relationships and individual attribute information. Finally, a set of feature descriptors is obtained from the TCM to capture the texture-related information of building groups. Through experiments on building pattern analysis and spatial queries, we show that the results of TCM-based evaluation of building patterns are consistent with those of human cognition.
作者机构：
[Ren, Zhoupeng; Ge, Yong] Chinese Acad Sci, State Key Lab Resources & Environm Informat Syst, Inst Geog Sci & Nat Resources Res, Beijing 100101, Peoples R China.;[Yuan, Yue; Wu, Yijin] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Hubei, Peoples R China.;[Hu, Shan] Xian Univ Sci & Technol, Coll Surveying & Mapping Sci & Technol, Xian 710054, Shaanxi, Peoples R China.;[Ge, Yong] Univ Chinese Acad Sci, Beijing 100049, Peoples R China.;[Ge, Yong] Jiangsu Ctr Collaborat Innovat Geog Informat Reso, Nanjing, Jiangsu, Peoples R China.
通讯机构：
[Ge, Yong] C;[Ge, Yong] U;[Ge, Yong] J;Chinese Acad Sci, State Key Lab Resources & Environm Informat Syst, Inst Geog Sci & Nat Resources Res, Beijing 100101, Peoples R China.;Univ Chinese Acad Sci, Beijing 100049, Peoples R China.
关键词：
Poverty alleviation performance;China's contiguous poverty-stricken regions;Space-time variability;Bayesian hierarchical model
摘要：
China has achieved significant achievements in poverty reduction since the launch of its reform and opening policy in 1978. The rural poor population decreased by nearly 67 million from 2010 to 2012. Analysing and understanding the spatio-temporal variation of poverty alleviation performance in contiguous poverty-stricken regions can provide a reference for Chinese policymakers. In this paper, based on the analytic hierarchy process (AHP), we build an evaluation index system of poverty alleviation performance and then establish a Bayesian spatio-temporal model to explore the space-time variability of poverty alleviation performance in poor areas. The spatial distribution indicates the eastern region's higher performance in poverty alleviation compared to the western region. The spatial-temporal feature shows that the increasing trend of poverty alleviation performance presents a pattern of "high in the central, low in the east-west'' and most poor counties' development of poverty alleviation performance are consistent with overall trend. These findings suggest that the government could pay more attention to the development in the western region and vigorously carry out precise poverty alleviation measures. (C) 2017 Elsevier B.V. All rights reserved.
摘要：
The grey value g (x, y)of pixel on radiometric spectrum is regarded as a function of the geometric coordinates (x, y). Hence, there is a unity of opposite relationships between the geometric and radiometric information, such that, these two types of information cannot be separated. Therefore, this paper proposes a novel geometric and radiometric simultaneous correction model (GRSCM) framework inspired and developed from least squares matching (LSM). Based on the Gauss-Markov model, geometric and radiometric correction coefficients are integrated and solved by an iterative method with variable weights in the proposed model. Moreover, many state-of-the-art models and methods can be integrated into the proposed general GRSCM framework. In the GRSCM of this paper, RAN-dom SAmple Consensus (RANSAC), step wise regression and significance testing are integrated and used. The experimental results demonstrate that the accuracy of the GRSCM is significantly improved compared with that of geometric correction and radiometric correction separately.
作者机构：
[Zhang, HuCai; Li, HuaYong; Zhang, WenXiang; Chang, FengQin] Yunnan Normal Univ, Key Lab Plateau Lake Ecol & Global Change, Yunnan Prov Key Lab Plateau Geog Proc & Environm, Coll Tourism & Geog Sci, Kunming 650500, Yunnan, Peoples R China.;[Li, HuaYong] Anyang Normal Univ, Sch Resource Environm & Tourism, Anyang 455000, Peoples R China.;[Zheng, Qian] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan 430079, Hubei, Peoples R China.;[Lei, GuoLiang] Fujian Normal Univ, Key Lab Subtrop Mt Ecol, Minist Sci & Technol & Fujian Prov Funded, Fuzhou 350007, Fujian, Peoples R China.;[Lei, YanBin] Chinese Acad Sci, Inst Tibetan Plateau Res, Lab Tibetan Environm Changes & Land Surface Proc, Beijing 100085, Peoples R China.
通讯机构：
[Zhang, HC; Chang, FQ] Y;Yunnan Normal Univ, Coll Tourism & Geog Sci, Key Lab Plateau Lake Ecol & Global Change, Yunnan Prov Key Lab Plateau Geog Proc & Environm, Kunming 650500, Yunnan, Peoples R China.
关键词：
Lake Zigetang;Tibetan Plateau;Meromictic lakes;Thermocline;Anoxygenic phototrophic bacteria
摘要：
Lake Zigetang is located on the central Tibetan Plateau (TP) and represents a rare but typical meromictic lake in China. The lake's stable meromixis sustains microflora communities, and changes in these communities are relatively independent of climate. Therefore, these communities can be used as paleoclimate proxies. In this paper, the stratification properties and their relationships with the microflora of Lake Zigetang were analyzed. We found that water depth and climate conditions were two important factors for maintaining meromixis in Lake Zigetang. Generally, stratification was enhanced during warm periods, while temperature differences between the mixolimnion and monimolimnion were decreased during cold periods. The presence of anoxygenic phototrophic bacteria (APB) was demonstrated by the discovery of bacteriopheophytin-a (Bph-a) in the sediments. This bacterial community is mainly concentrated at the bottom of the chemocline and the top of the monimolimnion, where it forms a thin APB layer. Moreover, total APB productivity is mainly affected by the light intensity penetrating to the APB layer, which exponentially increases as the thermocline becomes shallow. Therefore, high Bph-a values in the lake corresponded to a shallow thermocline and warm periods, low Bph-a values corresponded to cold periods, and zero changes indicated that the water was completely mixed and reflected an extreme cold climate or low lake level period. Thus, Bph-a can be used as a climate proxy to reconstruct the history of lake stratification and climate changes.
关键词：
time-series MODIS data;phenological feature;peak before wintering;winter wheat mapping
摘要：
By employing the unique phenological feature of winter wheat extracted from peak before winter (PBW) and the advantages of moderate resolution imaging spectroradiometer (MODIS) data with high temporal resolution and intermediate spatial resolution, a remote sensing-based model for mapping winter wheat on the North China Plain was built through integration with Landsat images and land-use data. First, a phenological window, PBW was drawn from time-series MODIS data. Next, feature extraction was performed for the PBW to reduce feature dimension and enhance its information. Finally, a regression model was built to model the relationship of the phenological feature and the sample data. The amount of information of the PBW was evaluated and compared with that of the main peak (MP). The relative precision of the mapping reached up to 92% in comparison to the Landsat sample data, and ranged between 87 and 96% in comparison to the statistical data. These results were sufficient to satisfy the accuracy requirements for winter wheat mapping at a large scale. Moreover, the proposed method has the ability to obtain the distribution information for winter wheat in an earlier period than previous studies. This study could throw light on the monitoring of winter wheat in China by using unique phenological feature of winter wheat.
