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Journal of Central South University 2014年第4期21卷 1508-1517页

作者：陶秋香刘国林 Geomatics College Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef of National Administration of surveying mapping and Geoinformation

The properties and feasibility of L-band differential InSAR for detecting and monitoring mining-induced subsidence were systematically analyzed and demonstrated. The largest monitored subsidence gradient of 7.9×10-3 and magnitude of 91 cm were firstly derived by theoretical derivation. Then, the stronger phase maintaining capacity and weaker sensitivity to minor land subsidence compared with C-band DInSAR were illustrated by phase simulation of the actual mine subsidence. Finally, the data processing procedure of two-pass DInSAR was further refined to accurately observe subsidence of a coalfield of Jining in Northern China using 7 ALOS PALSAR images. The largest monitored subsidence magnitude of 39.22 cm and other properties were better investigated by testing results interpretation and subsidence analysis, and the absolute difference varying from 0.5 mm to 17.9 mm was obtained by comparison with leveling-measured subsidence. All of results show that L-band DInSAR technique can investigate the location, amount, area and other detailed subsidence information with relatively higher accuracy.

关键词： L-band differential InSAR ALOS PALSAR mine subsidence monitoring

Altimetric Algorithm and Errors of Ocean Altimetry Using GNSS Reflection Signals

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China Ocean Engineering 2015年第6期29卷 933-944页

作者：郭金运王书阳刘新王建波常晓涛 College of Geodesy and Geomatics Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef of NASMG Satellite surveying and mapping Application Center of NASMG

As a new remote sensing technology, the global navigation satellite system（GNSS） reflection signals can be used to collect the information of ocean surface wind, surface roughness and sea surface height. Ocean altimetry based on GNSS reflection technique is of low cost and it is easy to obtain large amounts of data thanks to the global navigation satellite constellation. We can estimate the sea surface height as well as the position of the specular reflection point. This paper focuses on the study of the algorithm to determine the specular reflection point and altimetry equations to estimate the sea surface height over the reflection region. We derive the error equation of sea surface height based on the error propagation theory. Effects of the Doppler shift and the size of the glistening zone on the altimetry are discussed and analyzed at the same time. Finally, we calculate the sea surface height based on the simulated GNSS data within the whole day and verify the sea surface height errors according to the satellite elevation angles. The results show that the sea surface height can reach the precision of 6 cm for elevation angles of 55° to 90°, and the theoretical error and the calculated error are in good agreement.

关键词： GNSS refection technique sea surface height specular reflection point error propagation ocean altimetry

Correction for Depth Biases to Shallow Water Multibeam Bathymetric Data

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China Ocean Engineering 2013年第2期27卷 245-254页

作者：阳凡林李家彪刘智敏韩李涛 Geomatics College Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef NASG key laboratory of Submarine Geosciences of State Oceanic Administration

Vertical errors often present in multibeam swath bathymetric data. They are mainly sourced by sound refraction, internal wave disturbance, imperfect tide correction, transducer mounting, long period heave, static draft change, dynamic squat and dynamic motion residuals, etc. Although they can be partly removed or reduced by specific algorithms, the synthesized depth biases are unavoidable and sometimes have an important influence on high precise utilization of the final bathymetric data. In order to. confidently identify the decimeter-level changes in seabed morphology by MBES, we must remove or weaken depth biases and improve the precision of multibeam bathymetry further. The fixed-interval profiles that are perpendicular to the vessel track are generated to adjust depth biases between swaths. We present a kind of postprocessing method to minimize the depth biases by the histogram of cumulative depth biases. The datum line in each profile can be obtained by the maximum value of histogram. The corrections of depth biases can be calculated according to the datum line. And then the quality of final bathymetry can be improved by the corrections. The method is verified by a field test.

关键词： Multibeam Echosounder System depth biases correction shallow water

Route Height Connection Across the Sea by Using the Vertical Deflections and Ellipsoidal Height Data

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China Ocean Engineering 2013年第1期27卷 99-110页

作者：郭金运陈永宁刘新钟世霞麦照秋 College of Geodesy and Geomatics Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef of NASMG The 7th Terrestrial surveying Team of NASMG

Distance between the main land and island is so long that it is very difficult to precisely connect the height datum across the sea with the traditional method like the trigonometric leveling, or it is very expensive and takes long time to implement the height transfer with the geopotential technique. We combine the data of GPS surveying, astro-geodesy and EGM2008 to precisely connect the orthometric height across the sea with the improved astronomical leveling method in the paper. The Qiongzhou Strait is selected as the test area for the height connection over the sea. We precisely determine the geodetic latitudes, longitudes, heights and deflections of the vertical for four points on both sides across the strait. Modeled deflections of the vertical along the height connecting routes over the sea are determined with EGM2008 model based on the geodetic positions and heights of the sea segmentation points from DNSC08MSS model. Differences of the measured and modeled deflections of the vertical are calculated at four points on both sides and linearly change along the route. So the deflections of the vertical along the route over the sea can be improved by the linear interpolation model. The results are also in accord with those of trigonometirc levelings. The practical case shows that we can precisely connect the orthometric height across the Qiongzhou Strait to satisfy the requirement of order 3 leveling network of China. The method is very efficient to precisely connect the height datum across the sea along the route up to 80 km.

关键词： height connection across sea deflection of the vertical astro-geodesy orthometric height ellipsoidal height

Influence of higher-order ionospheric delay correction on GPS precise orbit determination and precise positioning

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Geodesy and Geodynamics 2016年第5期7卷 369-376页

作者： Zhimin Liu Yangyang Li Jinyun Guo Fei Li College of Geomatics Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef National Administration of SurveyingMapping and Geoinformation

At present, Global Navigation Satellite Systems（GNSS） users usually eliminate the influence of ionospheric delay of the first order items by dual-frequency ionosphere-free combination. But there is still residual ionospheric delay error of higher order term. The influence of the higher-order ionospheric corrections on both GPS precision orbit determination and static Precise Point Positioning（PPP） are studied in this paper. The influence of higher-order corrections on GPS precision orbit determination, GPS observations and static PPP are analyzed by neglecting or considering the higher-order ionospheric corrections by using a globally distributed network which is composed of International GNSS Service（IGS） tracking stations. Numerical experimental results show that, the root mean square（RMS） in three dimensions of satellite orbit is 36.6 mme35.5 mm. The maximal second-order ionospheric correction is 9 cm, and the maximal third-order ionospheric correction is 1 cm. Higher-order corrections are influenced by latitude and station distribution. PPP is within 3 mm in the directions of east and up. Furthermore, the impact is mainly visible in the direction of north, showing a southward migration trend, especially at the lower latitudes where the influence value is likely to be bigger than 3 mm.

关键词： Higher-order ionosphere Precision orbit determination PPP Geomagnetic model

Sea ice concentration over the Antarctic Ocean from satellite pulse altimetry

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Science China Earth Sciences 2011年第1期54卷 113-118页

作者： YANG YuanDe E DongChen WANG ,HaiHong CHAO DingBo HWANG CheinWay LI Fei AI SongTao Chinese Antarctic Center of surveying and mapping Wuhan University Wuhan 430079 China School of Geodesy and Geomatics Wuhan University Wuhan 430079 China key laboratory of surveying and mapping technology on island and reef State Bureau of surveying and mapping Qingdao 266510 China Department of Civil Engineering 'National' Chiao Tung University Hsinchu Taiwan China

Sea ice concentration (SIC) is an important parameter in characterizing sea ice. Limited by the environment and the spatial extent of observation, it is difficult for field work to meet the needs of a large-scale SIC study. However, with its many advantages, such as the ability to make large-scale, high-resolution and long-duration observations, the altimeter can be used to determine SIC on a large scale. Using the correspondence between the satellite pulse altimeter waveform and reflector property, waveform classification is employed. Moreover, this paper develops an algorithm to obtain the SIC from altimeter waveforms. In an actual computation, Pyrz Bay in the Antarctic is taken as an experimental region, and one-year and seasonal SICs are derived from ERS-1/GM waveforms over this study area. Furthermore, altimetric SICs are compared with those of SSMR SSM/I. The results show that the spatial distribution and the regions of maximum SIC determined employing these two methods are consistent. This demonstrates that altimeter data can be used to monitor sea ice.

关键词： sea ice concentration Antarctic altimeter waveform SSMR SSM/I ERS-1/GM

Improving Gravity Anomalies Over China Marginal Sea from Retracked Geosat and ERS-1 Data

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Geo-Spatial Information Science 2010年第2期13卷 144-149页

作者： WANG Haihong YANG Yuande HWANG Chenway CHU Yonghai MA Xinying School of Geodesy and Geomatics Wuhan University 129 Luoyu Road Wuhan 430079 China key laboratory of surveying and mapping technology on island and reef State Bureau of Surveying and Mapping 579 Qiangangwan Road Qingdao 266510 China Department of Civil Engineering Chiaotung University Hsingchu 30050 China Geodetic Data Processing Center State Bureau of Suneying and Mapping 334 East Youyi Road Xi'an 710054 China

The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.

关键词： satellite altimetry waveform retracking gravity anomaly tide model China marginal sea

Analysis of ionospheric anomaly preceding the Mw7.3 Yutian earthquake

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Geodesy and Geodynamics 2014年第2期5卷 54-60页

作者： Li Wang Guo Jinyun Yu Xuemin Yu Hongjuan College of Geodesy and Geomatics Shandong University of Science and Technology key laboratory of surveying and mapping technology on island and reef of NASMG

On February 12,2014,a large Mw7. 3 earthquake occurred in Yutian of Xijiang Province,*** processed the global ionosphere maps provided by CODE（ the Center for Orbit Determination in Europe）and the foF2（ the critical frequency of F2-layer） data of Chongqing ionosonde station to analyze the preearthquake ionospheric anomalies. Solar activities and magnetic storm were checked by the sliding inter quartile range method to remove their effects on the ionosphere. A positive ionospheric anomaly with the large amplitude of 20 TECU was observed near the epicenter on February 3（ 10th day before the earthquake）. In addition,the foF2 at Chongqing station had an unusual increase of more than 40% on the day,which was consistent with the TEC（ Total Electron Content） anomaly. The global disturbance represents that the peak of TEC anomaly didn’t coincide with the vertical projection of epicenter. The TEC anomalous area was closer to the equator,and it mainly occurred from local time 16 ∶ 00 to 20 ∶ 00. An enhancement of TEC with the small amplitude also appeared in the magnetically conjugated region.

关键词： Yutian earthquake ionosphere anomaly TEC foF2

Drivers,Trends,and Patterns of Changing Vegetation-greenness in Nansha islands,China from 2016 to 2022

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Chinese Geographical Science 2024年第4期34卷 662-673页

作者： TANG Jiasheng FU Dongjie SU Fenzhen YU Hao WANG Xinhui Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China State key laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Collaborative Innovation Center of South China Sea Studies Nanjing 210023China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Beijing North-Star technology Development Co. LtdBeijing 100120China

Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha islands,China and how they relate to climate change and human *** resolve this limitation,we studied changes to the Normalized Difference Vegetation Index(NDVI)vegetation-greenness index for 22 IRs of Nansha islands during normal and extreme *** of vegetation greenness were analyzed using Sen's slope and Mann-Kendall test at two spatial scales(pixel and island),and driving factor analyses were performed by time-lagged partial correlation *** were related to impacts from human activities and climatic factors under normal(temperature,precipitation,radiation,and Normalized Difference Built-up Index(NDBI))and extreme conditions(wind speed and latitude of IRs)from 2016 to *** showed:1)among the 22 IRs,NDVI increased/decreased significantly in 15/4 IRs,*** reef had the highest NDVI change-rate(0.48%/mon),and Zhongye island had the lowest(–0.29%/mon).Local spatial patterns were in one of two forms:dotted-form,and degradation in banded-form.2)Under normal conditions,human activities(characterized by NDBI)had higher impacts on vegetation-greenness than other factors.3)Under extreme conditions,wind speed(R^(2)=0.2337,Pislands and the United Nations‘Ocean Decade’initiative.

关键词： island and reefs(IRs) Normalized Difference Vegetation Index(NDVI) vegetation-greenness change-rate Sen's slope Nansha islands China

Polymer electrolytes for flexible zinc-air batteries:Recent progress and future directions

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Nano Research 2024年第7期17卷 6058-6079页

作者： Jing Wu Wen-Ya Wu Suxi Wang Dan Kai Enyi Ye Warintorn Thitsartarn Janet Beng Hoon Tan Jianwei Xu Qingyu Yan Qiang Zhu Xian Jun Loh Institute of Sustainability for Chemicals Energy and Environment(ISCE2)Agency for ScienceTechnology and Research(A*STAR)1 Pesek RoadJurong IslandSingapore 627833Singapore Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)2 Fusionopolis WayInnovis#08-03Singapore 138634Singapore School of Materials Science and Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological University21 Nanyang LinkSingapore 637371Singapore Department of Material Science and Engineering National University of Singapore9 Engineering Drive 1#03-09 EASingapore 117575Singapore

This review article delves into the development of electrolytes for flexible zinc-air batteries(FZABs),a critical component driving the advancement of flexible *** started by surveying the current advancements in electrolyte technologies,including solid-state and gel-based types,and their contributions to enhance the flexibility,efficiency,and durability of ***,we explored the challenges in this domain,focusing on maintaining electrolyte stability under mechanical stress,ensuring compatibility with flexible substrates,optimizing ion conductivity,and under harsh environmental ***,the key issues regarding interface details between electrolyte and the electrodes are covered as *** then discussed the future of electrolyte development in FZABs,highlighting potential avenues such as materials development,sustainability,in-situ studies,and battery *** review offers an in-depth overview of the advancements,challenges,and potential breakthroughs in creating electrolytes for FZABs over the past five *** serves as a guide for both researchers and industry professionals in this dynamic area.

关键词： flexible zinc-air batteries electrolyte polymer hydrogel electrolyte-electrode interface