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Predicting bathymetry based on vertical gravity gradient anomaly and analyses for various influential factors

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Geodesy and Geodynamics 2024年第4期15卷 386-396页

作者： Huan Xu Jinhai Yu Yanyan Zeng Qiuyu Wang Yuwei Tian Zhongmiao Sun College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina Beijing Institute of surveying and mapping BeijingChina National Key Laboratory of Geoinformation Engineering Xi'an 710054China

The prediction of bathymetry has advanced significantly with the development of satellite ***,the majority of its data originate from marine gravity *** this study,based on the expression of vertical gravity gradient(VGG)of a rectangular prism,the governing equations for determining sea depths to invert *** governing equation is solved by linearization through an iterative process,and numerical simulations verify its algorithm and its *** also study the processing methods of different interference *** regularization method improves the stability of the inversion process for errors.A piecewise bilinear interpolation function roughly replaces the low-frequency error,and numerical simulations show that the accuracy can be improved by 41.2%after this *** variable ocean crust density,simulation simulations verify that the root-mean-square(RMS)error of prediction is approximately 5 m for the sea depth of 6 km if density is chosen as the average ***,two test regions in the South China Sea are predicted and compared with ship soundings data,RMS errors of predictions are 71.1 m and 91.4 m,respectively.

关键词： Rectangular prism Vertical gravity gradient Bathymetry Numerical simulation Prediction error

Neomicrocoleus ***.(Microcoleaceae,Oscillatoriales),a novel cyanobacterial genus from benthic mats in a water channel

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Journal of Oceanology and Limnology 2024年第1期42卷 263-276页

作者： Ruozhen GENG Zhongshi HE Kaihui GAO Peng XIAO He ZHANG Si CHEN Hua LI Gongliang YU Renhui LI College of Life and Environmental Sciences Wenzhou UniversityWenzhou 325035China Key Laboratory of Algal Biology Institute of HydrobiologyChinese Academy of SciencesWuhan 430072China University of chinese academy of Sciences Beijing 100049China Hubei Institution of Land surveying and mapping Wuhan 430072China

A new filamentous cyanobacterial strain(CHAB 4127)was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin,*** polyphasic approach combining morphological,ultrastructural,ecological,and molecular features was used to characterize this studied *** strain is morphologically similar to the Microcoleus-like cyanobacterial taxa under light microscopy,and the radial arrangement of thylakoids is also consistent with that of Microcoleus-like *** phylogenetic position of CHAB 4127 based on 16S rRNA gene sequences,is shown to be clearly clustered into an independent clade with the newly established genus *** maximum similarity of 16S r RNA gene of the studied strain with other existing related cyanobacterial taxa is 93.97%,and the ITS secondary structures is also obviously different from other members of *** on all the above evidence,we proposed the establishment of this novel cyanobacterial genus as Neomicrocoleus,with its type species,Neomicrocoleus tianjinensis.

关键词： Neomicrocoleus tianjinensis morphology 16S rRNA taxonomy polyphasic approach

Hourly land surface temperature retrieval over the Tibetan Plateau using Geo-LightGBM framework: Fusion of Himawari-8 satellite, ERA5 and site observations

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Advances in Climate Change Research 2024年第4期15卷 623-635页

作者： Zhao-Hua LIU Shan-Shan WENG Zhao-Liang ZENG Ming-Hu DING Ya-Qiang WANG Zhehao LIANG Civil and surveying&mapping Engineering Jiangxi University of Science and TechnologyGanzhou 341000China State Key Laboratory of Severe Weather chinese academy of Meteoroogical Sciences Beijing 100081China Space Geodesy and Geoinformation Technical Unviersity of BerlinBerlin 10623Germany

The Tibetan Plateau(TP)is highly sensitive to even minor fluctuations in land surface temperature(LST),which can result in permafrost melting and degradation of alpine grasslands,leading to serious ecological ***,it is crucial to have high-temporal-resolution and seamless hourly estimating and monitoring of LST for a better understanding of climate change on the ***,we employed Himawari-8 satellite,Digital Elevation Model(DEM),ERA5 reanalysis and meteorological station observations data to develop a new LightGBM framework(called Geo-LightGBM)for estimating LST on the TP,and then analyzed the spatiotemporal variations of those ***-LightGBM demonstrated excellent LST estimation accuracy,with an R2(coefficient of determination)of 0.971,RMSE(root-mean-square error)of 2.479℃,and MAE(mean absolute error)of 1.510℃.The estimated LST values for the year 2020 agreed well with observed values,with remarkable differences in hourly LST ***,the estimated LST was more accurate than that from ***,there were two high LST centers,located in the Yarlung Zangbo River Basin and the Qaidam Basin,and a low LST center located in the central *** SHAP(SHapley Additive exPlanations)and correlation analyses revealed DSCS(the mean ground downward shortwave radiation under clear-sky conditions)to be the most importantly input variable for estimating *** dummy variables(e.g.,longitude,latitude,DEM)were also found to be crucial for model accuracy *** findings indicate the potential for constructing a high-precision and seamless 24-h LST real-time retrieval and monitoring platform for the TP by combining satellite and China's independently developed CLDAS(China Land Data Assimilation System)data in future.

关键词： Tibetan Plateau Himawari-8 ERA5 Land surface temperature Geo-LightGBM

Retrieval of Antarctic sea ice freeboard and thickness from HY-2B satellite altimeter data

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Acta Oceanologica Sinica 2024年第3期43卷 87-101页

作者： Yizhuo Chen Xiaoping Pang Qing Ji Zhongnan Yan Zeyu Liang Chenlei Zhang chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhan 430079China Key Laboratory of Polar surveying and mapping Science Ministry of Natural ResourcesWuhan 430079China Key Laboratory of Polar Environment Monitoring and Public Governance Ministry of EducationWuhan 430079China 4 School of Geography and Tourism Anhui Normal UniversityWuhu 241002China

Antarctic sea ice is an important part of the Earth’s atmospheric system,and satellite remote sensing is an important technology for observing Antarctic sea *** chinese Haiyang-2B(HY-2B)satellite altimeter data could be used to estimate sea ice freeboard and provide alternative Antarctic sea ice thickness information with a high precision and long time series,as other radar altimetry satellites can,needs further *** paper proposed an algorithm to discriminate leads and then retrieve sea ice freeboard and thickness from HY-2B radar altimeter *** first collected the Moderate-resolution Imaging Spectroradiometer ice surface temperature(IST)product from the National Aeronautics and Space Administration to extract leads from the Antarctic waters and verified their accuracy through Sentinel-1 Synthetic Aperture Radar ***,a surface classification decision tree was generated for HY-2B satellite altimeter measurements of the Antarctic waters to extract leads and calculate local sea surface *** then estimated the Antarctic sea ice freeboard and thickness based on local sea surface heights and the static equilibrium ***,the retrieved HY-2B Antarctic sea ice thickness was compared with the CryoSat-2 sea ice thickness and the Antarctic Sea Ice Processes and Climate(ASPeCt)ship-based observed sea ice *** results indicate that our classification decision tree constructed for HY-2B satellite altimeter measurements was reasonable,and the root mean square error of the obtained sea ice thickness compared to the ship measurements was 0.62 *** proposed sea ice thickness algorithm for the HY-2B radar satellite fills a gap in this application domain for the HY-series satellites and can be a complement to existing Antarctic sea ice thickness products;this algorithm could provide long-time-series and large-scale sea ice thickness data that contribute to research on global climate change.

关键词： HY-2B satellite altimeter classification decision tree sea ice freeboard and thickness Antarctic waters

Status and trends in the stability of the three largest ice shelves in Antarctica

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Science China Earth Sciences 2024年第8期67卷 2615-2632页

作者： Rongxing LI Guojun LI Lu AN Menglian XIA Da LV Yuan CHENG Aiguo ZHAO Tian CHANG Xiangbin CUI Shengkai ZHANG Shijie LIU Yixiang TIAN Weian WANG Center for Spatial Information Science and Sustainable Development Applications Tongji UniversityShanghai 200092China College of surveying and Geo-informatics Tongji UniversityShanghai 200092China Postdoctoral Research Station of Shanghai surveying and mapping Institute Shanghai 200063China Key Laboratory of Spatial-temporal Big Data Analysis and Application of Natural Resources in Megacities Shanghai 200063China Institute for Conservation of Cultural Heritage School of Cultural Heritage and Information ManagementShanghai UniversityShanghai 200444China Polar Research Institute of China Shanghai 200136China chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhan 430079China

The Ross,Filchner-Ronne,and Amery ice shelves are the three largest ice shelves in Antarctica,playing a crucial role in supporting the Antarctic ice ***,current studies on the stability of the three largest ice shelves primarily focus on singular or limited factors,lacking a comprehensive assessment of multiple *** systematically and in-depth study the stability and trend of the three largest ice shelves,we comprehensively collected and analyzed key parameters,including elevation changes,basal melting,surface meltwater,major rifts propagation rate,suture zones,ice front area change rate,grounding lines,ice velocity,and mass ***,we selected the collapsed Larsen B Ice Shelf(LBIS),the rapidly changing and structurally weakened Pine Island Ice Shelf(PIIS),and the accelerating Totten Ice Shelf(TIS)as reference ice *** comparing and analyzing the key parameters between these reference ice shelves and the three largest ice shelves,we find the status and trends in the stability of the *** findings reveal that most key parameters of the three largest ice shelves present relatively minor variations compared to those of the reference ice ***,50%of the parameters are smaller than those of the accelerating TIS,88%are smaller than those of the rapidly changing PIIS,and all parameters are smaller than those of the collapsed ***,after analyzing parameters that are not smaller than those of the TIS,it is observed that they remain in a stable ***,the three largest ice shelves are currently undergoing natural changes that do not threaten their stability in the short ***,the evolution of the ice shelves under global climate change remains uncertain,making long-term observation and monitoring essential to assess their impact on sea level rise.

关键词： Three largest ice shelves in Antarctica Key parameters Remote sensing monitoring Ice shelf stability Sea level change

Effects of Enclosure on Grassland Ecological and Economic Benefits in Northern China

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chinese Geographical Science 2024年第1期34卷 67-78页

作者： HU Bo WEN Qingke XI Fengjiang LI Mengyao WANG Libing REN Yuejuan Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China University of chinese academy of Sciences Beijing100049China Inner Mongolia Remote Sensing Center Co. Ltd.Huhhot010000China Xilinhot the Maodeng pasture Xilinhot026000China China University of Mining and Technology Xuzhou221116China Shanxi Provincial Key Lab of Resources Environment and Disaster MonitoringCoal Geological Geophysical Exploration Surveying&Mapping Institute of Shanxi ProvinceJinzhong030600China

Grasslands in northern China serve the country as both an ecological barrier and a livestock production ***,installing enclosures has been becoming the major grassland restoration measure adopted by many local ***,the effects of restoration on both ecological and production benefits of grassland remain unclear for implemented grassland restoration ***,a representative rangeland in northern China,the Maodeng pasture in Inner Mongolia Autonomous Region was selected as the study area,and remote sensing monitoring analyses were carried out to quantify the ecological benefits and economic benefits from 2015 to *** results showed that:1) in terms of ecological benefits,the grassland area with a grassland coverage rate of more than 60% accounts for 32.3% of the regional area,and 86.4% of its grassland grew significantly better than the same period in2015,showing a significant improvement in grassland *** the average amount of carbon per unit area as the ecological benefit evaluation index,it increased by 27.1% to 32.48Tg C/yr from 2015 to 2021.2) In terms of economic benefits,both theoretical grass production and livestock carrying capacity increased from 2015 to *** to 2015,the theoretical grass production in 2021 increased by 24.8% to 71 900 *** livestock carrying capacity reached 52 100 sheep units in 2021,nearly 11 000 sheep units more than that in *** the study period,multiple economic indicators(on a per capita basis of permanent residents) for the pastoral area of Xilinhot City to which the Maodeng pasture belongs,have grown *** capita total income rose from 29 630 yuan(RMB) in2015 to 62 859 yuan(RMB) in *** on grassland resources to develop the pastoral ecology also broadens the potential economic development ***,the establishment of the reserve and the experiment of implanting an enclosure policy have had a significant and positive impact on Maodeng pasture’s develo

关键词： enclosure grassland ecological benefit economic benefit Maodeng pasture Inner Mongolia northern China

The GNSS PWV retrieval using non-observation meteorological parameters based on ERA5 and its relation with precipitation

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Geodesy and Geodynamics 2024年第3期15卷 302-313页

作者： Weifeng Yang Zhiping Chen Kaiyun Lv Pengfei Xia Tieding Lu School of surveying and Geoinformation Engineering East China University of TechnologyNanchang 330013China Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake of Ministry of Natural Resources East China University of TechnologyNanchang 330013China State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China Jiangxi Province Engineering Research Center of surveying Mapping and Geographic InformationNanchang 330025China School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China

The pressure and temperature significantly influence precipitable water vapor(PWV) retrieval. Global Navigation Satellite System(GNSS) PWV retrieval is limited because the GNSS stations lack meteorological sensors. First, this article evaluated the accuracy of pressure and temperature in 68 radiosonde stations in China based on ERA5 Reanalysis data from 2015 to 2019 and compared them with GPT3model. Then, the accuracy of pressure and temperature calculated by ERA5 were estimated in 5 representative IGS stations in China. And the PWV calculated by these meteorological parameters from ERA5(ERA5-PWV) were analyzed. Finally, the relation between ERA5-PWV and precipitation was deeply explored using wavelet coherence analysis in IGS stations. These results indicate that the accuracy of pressure and temperature of ERA5 is better than the GPT3 model. In radiosonde stations, the mean BIAS and MAE of pressure and temperature in ERA5 are-0.41/1.15 hpa and-0.97/2.12 K. And the mean RMSEs are 1.35 hpa and 2.87 K, which improve 74.77% and 40.58% compared with GPT3 model. The errors of pressure and temperature of ERA5 are smaller than the GPT3 model in bjfs, hksl and wuh2, and the accuracy of ERA5-PWV is improved by 18.77% compared with the GPT3 model. In addition, there is a significant positive correlation between ERA5-PWV and precipitation. And precipitation is always associated with the sharp rise of ERA5-PWV, which provides important references for rainfall prediction.

关键词： ERA5 GNSS Precipitable water vapor Precipitation Wavelet coherence analysis

通过空间结构及网络稳健性理解协同发展--以京津冀地区为例

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Journal of Geographical Sciences 2024年第5期34卷 1007-1036页

作者：王浩张校源张晓宇刘若文宁晓刚 chinese academy of surveying and mapping Beijing 100036China School of Information Engineering China University of GeosciencesBeijing 100083China College of Land Science and Technology China Agricultural UniversityBeijing 100193China

In the context of accelerated globalization,intercity factor flows are becoming in-creasingly dependent on a reasonable and orderly spatial ***,an indepth study of the optimization and adjustment of spatial structure is essential for coordinated *** study quantitatively evaluated urban development levels and introduced network analysis methods to analyse the spatial structure and robustness of *** results indicated the following:(1)The urban development level in the Beijing-Tianjin-Hebei(BTH)region increased in all dimensions,and the transmission efficiency significantly improved.(2)The spatial structure of the BTH region has been relatively stable,as illustrated by the main pattern of the spatial distribution of central cities,with a trend towards contiguous development.(3)The ranking of network robustness is environment>society>economy,and the core network and key nodes are primarily located within the radiation of the three central cities of Beijing,Tianjin,and Shijiazhuang.(4)The coordinated development of the BTH region is effective but still needs to be optimized and adjusted,and the strategic significance of edge cities has not been completely *** study aims to provide an emerging ana-lytical perspective for optimizing regional spatial structure and promoting regional coordinated development.

关键词： urban network spatial structure network robustness coordinated development Beijing-Tianjin-Hebei(BTH)region

Reconciled estimation of Antarctic ice sheet mass balance and contribution to global sea level change from 1996 to 2021

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Science China Earth Sciences 2024年第11期67卷 3562-3578页

作者： Rongxing LI Guojun LI Gang HAI Huan XIE Yuan CHENG Wei CHEN Xiangbin CUI Minghu DING Chunchun GAO Tong HAO Changqing KE Chuanjin LI Jin LI Yan LIU Jiangjun RAN Jiawen REN Qiang SHEN Yunzhong SHEN Hongling SHI Songyun WANG Zemin WANG Jingang ZHAN Baojun ZHANG Min ZHONG Chunxia ZHOU Center for Spatial Information Science and Sustainable Development Applications Tongji University College of surveying and Geo-informatics Tongji University Institute for the Conservation of Cultural Heritage School of Cultural Heritage and Information Management Shanghai University College of Resource Environment and Tourism Hubei University of Arts and Science Polar Research Institute of China State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences College of Geodesy and Geomatics Shandong University of Science and Technology School of Geography and Ocean Science Nanjing University Shanghai Astronomical Observatory Chinese Academy of Sciences State Key Laboratory of Remote Sensing Science Faculty of Geographical Science Beijing Normal University Department of Earth and Space Sciences Southern University of Science and Technology State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of Sciences Center for Space Research University of Texas at Austin chinese Antarctic Center of surveying and mapping Wuhan University School of Geospatial Engineering and Science Sun Yat-sen University

The Antarctic Ice Sheet（AIS） has been losing ice mass and contributing to global sea level rise（GSLR）. Given its mass that is enough to cause ～58 m of GSLR, accurate estimation of mass balance trend is critical for AIS mass loss monitoring and sea level rise forecasting. Here, we present an improved approach to reconciled solutions of mass balance in AIS and its regions from multiple contributing solutions using the input-out, altimetric, and gravimetric methods. In comparison to previous methods, such as IMBIE 2018, this approach utilizes an adaptive data aggregation window to handle the heterogeneity of the contributing solutions, including the number of solutions, temporal distributions, uncertainties, and estimation techniques. We improved the regression-based method by using a two-step procedure that establishes ensembled solutions within each method（input-output, altimetry, or gravimetry） and then estimates the method-independent reconciled solutions. For the first time, 16contributing solutions from 8 chinese institutions are used to estimate the reconciled mass balance of AIS and its regions from1996 to 2021. Our results show that AIS has lost a total ice mass of ～3213±253 Gt during the period, an equivalent of～8.9±0.7 mm of GSLR. There is a sustained mass loss acceleration since 2006, from 88.1±3.6 Gt yr-1during 1996–2005 to 130.7 ±8.4 Gt yr-1during 2006–2013 and further to 157.0±9.0 Gt yr-1during 2014–2021. The mass loss signal in the West Antarctica and Antarctic Peninsula is dominant and clearly presented in the reconciled estimation and contributing solutions, regardless of estimation methods used and fluctuation of surface mass balance. Uncertainty and challenges remain in mass balance estimation in East Antarctica. This reconciled estimation approach can be extended and applied for improved mass balance estimation in the Greenland Ice Sheet and mountain glacier regions.

关键词： Antarctic Ice Sheet Ice mass loss acceleration Sea level rise Reconciled estimation