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The shifts of precipitation phases and their impacts

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Science China Earth Sciences 2025年

作者： Xuemei LI Tao CHE Yuanlong TANG Huan'e DUAN Guigang WANG Xu ZHANG Chuanming YANG Jun WU Yue ZHANG Lanhai LI Faculty of Geomatics Lanzhou Jiaotong University National-Local Joint Engineering Research Center of Technologies and Applications for National Geographic state Monitoring key laboratory of Science and Technology in surveying & Mapping Gansu Province key laboratory of Cryospheric Science and Frozen Soil Engineering Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Xinjiang key laboratory of Water Cycle and Utilization in Arid Zone Xinjiang Institute of Ecology and Geography Chinese academy of Sciences Tianshan Snow Cover and Avalanche Observation and Research Station of Xinjiang

Precipitation comes in various phases, including rainfall, snowfall, sleet, and hail. Shifts of precipitation phases, as well as changes in precipitation amount, intensity, and frequency, have significant impacts on regional climate, hydrology,ecology, and the energy balance of the land-atmosphere system. Over the past century, certain progress has been achieved in aspects such as the observation, discrimination, transformation, and impact of precipitation phases. Mainly including:since the1980s, studies on the observation, formation mechanism, and prediction of precipitation phases have gradually received greater attention and reached a certain scale. The estimation of different precipitation phases using new detection theories and methods has become a research focus. Avariety of discrimination methods or schemes, such as the potential thickness threshold method of the air layer, the temperature threshold method of the characteristic layer, and the near-surface air temperature threshold method,have emerged one after another. Meanwhile, comparative studies on the discrimination accuracy and applicability assessment of multiple methods or schemes have also been carried out simultaneously. In recent years, the shift of precipitation from solid to liquid (SPSL) in the mid-to-high latitudes of the Northern Hemisphere has become more pronounced due to global warming and human activities. It leads to an increase in rain-on-snow (ROS) events and avalanche disasters, affecting the speed, intensity, and duration of spring snow-melting, accelerating sea ice and glacier melting, releasing carbon from permafrost, altering soil moisture, productivity, and phenological characteristics of ecosystems, and thereby affecting their structures, processes, qualities, and service functions. Although some progress has been made in the study of precipitation phases, there remains considerable research potential in terms of completeness of basic data, reliability of discrimination schemes,

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Space-based information service in Internet Plus Era

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Science China(Information Sciences) 2017年第10期60卷 229-238页

作者： Deren LI Xin SHEN Nengcheng CHEN Zhifeng XIAO state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan University

"Internet Plus" represents a new form of society that provides a vast platform for reform, innovation,and development. Given the continued integration of the Internet in many fields, Internet Plus is profoundly transforming and influencing a variety of traditional industries. Internet Plus has created conditions favorable for the transformation of earth observation and satellite navigation into an intelligent and real-time geospatial information service. The authors propose that in order to implement continuous, all-weather, all-terrain services for the specific purposes of each individual, it will be necessary to overcome the flaws in existing space-based information systems, such as limited regional coverage, slow response, and weak interoperability. Furthermore, to meet the Big Data Era’s geospatial information service requirements, an "Internet Plus Space-Based Information Service" system, intrinsically linked to ground Internet networks, will have to be constructed. With reference to the developments of aerospace information technology, this paper discusses three levels of the proposed structure of the Internet Plus space-based information service system and ideas for its implementation. Finally,in recognition of the demands facing the Internet Plus space-based information service system, the prospects for geomatics and important supporting technologies are examined.

关键词： Internet Plus space-based information service space information network satellite remote sensing satellite navigation satellite communication

Assimilating ASAR Data for Estimating Soil Moisture Profile Using an Ensemble Kalman Filter

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Chinese Geographical Science 2013年第6期23卷 666-679页

作者： YU Fan LI Haitao GU Haiyan HAN Yanshun key laboratory of Geo-Informatics of state Bureau of surveying and Mapping Chinese Academy of Surveying and Mapping

Active microwave remote sensing data were used to calculate the near-surface soil moisture in the vegetated *** this study,Advanced Synthetic Aperture Radar(ASAR)observations of surface soil moisture content were used in a data assimilation framework to improve the estimation of the soil moisture profile at the middle reaches of the Heihe River Basin,Northwest China.A one-dimensional soil moisture assimilation system based on the ensemble Kalman filter(EnKF),the forward radiative transfer model,crop model,and the Distributed Hydrology-Soil-Vegetation Model(DHSVM)was *** crop model,as a semi-empirical model,was used to estimate the surface backscattering of vegetated *** DHSVM is a distributed hydrology-vegetation model that explicitly represents the effects of topography and vegetation on water fluxes through the *** experiments were conducted to assimilate the ASAR data into the DHSVM and in situ soil moisture at the middle reaches of the Heihe River Basin from June20 to July 15,*** results indicated that EnKF is effective for assimilating ASAR observations into the hydrological *** with the simulation and in situ observations,the assimilated results were significantly improved in the surface layer and root layer,and the soil moisture varied slightly in the deep ***,EnKF is an efficient approach to handle the strongly nonlinear problem which is practical and effective for soil moisture estimation by assimilation of remote sensing ***,to improve the assimilation results,further studies on obtaining more reliable forcing data and model parameters and increasing the efficiency and accuracy of the remote sensing observations are needed,also improving estimation accuracy of model operator is important.

关键词： assimilation ensemble Kalman filter (EnKF) soil moisture hydrological model Advanced Synthetic Aperture Radar(ASAR)

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Understanding the Moon's internal structure through moonquake observations and remote sensing technologies

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Science China Earth Sciences 2018年第8期61卷 995-1006页

作者： Weifeng HAO Fei LI Chi XIAO Jianguo YAN Mao YE Chinese Antarctic Center of surveying and Mapping Wuhan University state key laboratory of Information Engineering in surveying Mapping and Remote Sensing Wuhan University

Explorations for the interior structure of the Moon mainly involve three technologies: the early gravitational observations via circumlunar satellites, the moonquake observations during the Apollo period, and the recent high-resolution remote sensing observations. Based on these technologies, we divided the development of the moon's interior structure into three stages. The first stage is the discovery of high-density anomalous masses(mascons) on the lunar surface with the low-order gravitational field models, which were obtained by observing perturbations of the early lunar orbital satellites. The second stage is the preliminary understanding of the layer structure with the help of moonquake observations during the Apollo period. The third stage is the deep understanding of the structure of the lunar crust, mantle, and core, with the use of high-resolution remote sensing data and the reassessment of moonquake data from the Apollo's mission. This paper gave detailed introduction and comments on different observation technologies, gathered data, and data processing techniques used at the three stages. In addition, this paper analyzed the current issues in the researches on the Moon's internal structure and discussed the prospects for future explorations.

关键词： Moon Mascon Moonquake Remote sensing Lunar internal structure

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Review on graph learning for dimensionality reduction of hyperspectral image

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Geo-Spatial Information Science 2020年第1期23卷 98-106页

作者： Liangpei Zhang Fulin Luo state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Graph learning is an effective manner to analyze the intrinsic properties of *** has been widely used in the fields of dimensionality reduction and classification for *** this paper,we focus on the graph learning-based dimensionality reduction for a hyperspectral ***,we review the development of graph learning and its application in a hyperspectral ***,we mainly discuss several representative graph methods including two manifold learning methods,two sparse graph learning methods,and two hypergraph learning *** manifold learning,we analyze neighborhood preserving embedding and locality preserving projections which are two classic manifold learning methods and can be transformed into the form of a *** sparse graph,we introduce sparsity preserving graph embedding and sparse graph-based discriminant analysis which can adaptively reveal data structure to construct a *** hypergraph learning,we review binary hypergraph and discriminant hyper-Laplacian projection which can represent the high-order relationship of data.

关键词： Hyperspectral image dimensionality reduction classification graph learning

A novel method for road network mining from floating car data

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Geo-Spatial Information Science 2022年第2期25卷 197-211页

作者： Yuan Guo Bijun Li Zhi Lu Jian Zhou state key laboratory of Information Engineering in surveying Mappingand Remote SensingWuhan UniversityWuhanChina

Vehicles have been increasingly equipped with GPS receivers to record their trajectories,which we call floating car *** with other data sources,these data are characterized by low cost,wide coverage,and rapid *** data have become an important source for road network *** this paper,we propose a novel approach for mining road networks from floating car ***,a Gaussian model is used to transform the data into bitmap,and the Otsu algorithm is utilized to detect road ***,a clothoid-based method is used to resample the GPS points to improve the clustering accuracy,and the data are clustered based on a distance-direction ***,road centerlines are extracted with a weighted least squares *** report on experiments that were conducted on floating car data from Wuhan,*** conclude,existing methods are compared with our method to prove that the proposed method is practical and effective.

关键词： GPS trajectory floating car data road intersection extraction data clustering

Large-scale automatic block adjustment from satellite to indoor photogrammetry

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Geo-Spatial Information Science 2023年第2期26卷 160-174页

作者： Deren Li Bo Yang Mi Wang Taiping Wang Yunlong Gao Yingdong Pi state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Block Adjustment(BA)is a critical procedure in the geometric processing of satellite images,responsible for compensating and correcting the geometric positioning errors of the *** accuracy of the photogrammetric products,including Digital Orthophoto Map(DOM),Digital Elevation Model(DEM),Digital Line Graphic(DLG),and Digital Raster Graphic(DRG),directly depends on the accuracy of BA *** recent years,the rapid development of related technologies such as Artificial Intelligence(AI),Computer Vision(CV),Unmanned Aerial Vehicles(UAVs)and big data has greatly facilitated and transformed the classical BA in *** paper first reviews the current status of BA and then looks into the ***,this paper provides a brief review of the key technologies involved in BA,including image matching,the establishment of adjustment model,the determination of the parameters and the detection of gross ***,taking the intercross and fusion of current technologies such as AI,cloud computing and big data with photogrammetry into account,this paper explores the future trends of ***,four typical cases of large-scale adjustment are introduced,including large-scale BA without Ground Control Points(GCPs)for optical stereo satellite images,large-scale BA with laser altimetry data for optical stereo satellite images,large-scale BA for UAV oblique photogrammetry,and large-scale BA for indoor photogrammetry in caves with a large number of close-range images.

关键词： Block Adjustment(BA) large-scale image matching control points review

Multipath tracking with LTE signals for accurate TOA estimation in the application of indoor positioning

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Geo-Spatial Information Science 2023年第1期26卷 31-43页

作者： Zhaoliang Liu Liang Chen Xin Zhou Nan Shen Ruizhi Chen The state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Indoor positioning with high accuracy plays an important role in different application *** a widely used mobile communication signal,the Long-Term Evolution(LTE)network can be well received in indoor and outdoor *** article studies a method of using different reference signals in the LTE downlink for carrier phase time of arrival(TOA)***,a solution is proposed and a multipath tracking Software Defined Receiver(SDR)is developed for indoor *** our SDR indoor positioning system,the pilot signals of the LTE signals are firstly obtained by the coarse synchronization and ***,with the assistance of the pilot signals,the time delay acquisition,the multipath estimating delay lock loop(MEDLL)algorithm,and the multipath anomaly detection are sequentially carried out to obtain navigation observations of received ***,to compare the perfor-mance of different pilot signals,the Secondary Synchronous Signals(SSS)and Cell Reference Signals(CRS)are used as pilot signals for carrier phase-based TOA estimation,***,to quantify the accuracy of our multipath tracking SDR,indoor field tests are carried out in a conference environment,where an LTE base station is installed for commercial *** test results based on CRS show that,in the static test scenarios,the TOA accuracy measured by the 1-σerror interval is about 0.5 m,while in the mobile environment,the probability of range accuracy within 1.0 m is 95%.

关键词： Long-Term Evolution(LTE) indoor positioning multipath estimation delay locked loop(MEDLL) carrier phase time of arrival(TOA)

Non-rigid registration of mural images and laser scanning data based on the optimization of the edges of interest

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Science China(Information Sciences) 2013年第6期56卷 181-190页

作者： ZHANG Fan HUANG XianFeng FANG Wei LI DeRen state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan University

The orientation and correction of mural images by registering them with laser scanning data is critical for the digital protection of ancient *** paper proposes a method for the non-rigid registration of mural images and laser scanning data based on the optimization of the edge of interest by using laser echo intensity information as an ***,the intensity image was generated from the laser echo intensity information,and registered with the mural image using a rigid transformation ***,the edges of interest in the mural image and the gradient field of the intensity images were processed as registration ***,every edge of interest was registered with the optimization base used in the rigid registration of the mural image and intensity ***,the registration was completed after a non-rigid transformation model between these two images was constructed using the control points on the optimized *** experimental results show that the proposed method can obtain high registration accuracy for different data sets.

关键词： laser scanning point cloud image registration non-rigid