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Comparison of bulk snow density measurements using different methods

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Advances in Climate Change Research 2024年第4期15卷 658-668页

作者： Hang SU Xin-Yue ZHONG Bin CAO Yuan-Tao HU Lei ZHENG Tingjun ZHANG state Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of remote sensing of Gansu Province Heihe Remote Sensing Experimental Research StationNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Tibetan Plateau Earth System Environment and ResourcesNational Tibetan Plateau Data CenterInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Climate centre of Shaanxi Province Xi'an71000China School of Geospatial Engineering and Science Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Westem China's environmental Systems(Ministry of Education).College of Earth and environmental Sciences Lanzhou Universiny Lanzhou 730000China

Snow density is one of the basic properties used to describe snow cover characteristics,and it is critical for remote sensing retrieval,water resources assessment and modeling *** are many instruments available to measure snow density in ***,there are mea-surement errors of snow density for bulk and layers or gravimetric and electronic instruments,which may affect the accuracy of remote sensing retrieval and model *** in China,due to the noticeable heterogeneity of snowpacks,it is necessary to evaluate in detail the performance and applicability of snow density instruments in different snowpack *** study evaluated the performance of different snow density instruments:the Federal Sampler,the model VS-43 snow density cylinder(VS-43),the wedge snow density cutter(WC1000 and WC25O),and the Snow *** average bulk snow density of all instrument measurements was set as the reference value for *** results showed that as compared with the reference,the VS-43 cylinder presented the best performance for bulk snow density measurement in the measured range with the lowest RMSE(11 kg m-3),BIAS(3 kg m-3),and MRE(1.6%).For layer observation,bulk snow density was overestimated by 8.1%with WC1000 and underestimated by 11.4%with Snow Fork which was the worst performance compared with the reference value,and there were greater measurement errors of snow density in the depth hoar than other snow *** with grassland,the uncertainty of snow density measurements was slightly lower in ***,the Federal Sampler and VS-43 cylinder are more suitable for bulk snow density measurement in deep snowpack regions across China,and it is recommended to use WC1000,WC250 and Snow Fork to measure the snow density of snow layers in the snow stratigraphy.

关键词： Snowdensity Measurement Uncertainty comparison

Spatiotemporal Variation of Water Cycle Intensity in the Pamir Plateau from 1980 to 2019 and Its Climatic Drivers

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Journal of Earth Science 2024年

作者： Jingjing Zhang Lingxin Kong Long Ma Majid Gulayozov Anvar Kodirov Jilili Abuduwaili state Key Laboratory of Desert and Oasis Ecology Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Research Center for Ecology and environment of Central Asia Chinese Academy of Sciences University of Chinese Academy of Sciences China-Kazakhstan Joint Laboratory for remote sensing Technology and Application Al-Farabi Kazakh National University Research Center for Ecology and environment of Central Asia (Dushanbe) centre for Innovative Development of Science and New Technologies National Academy of Science of Tajikistan

A comprehensive understanding of the hydrological cycle is essential for Earth system science and climate change research. The Water Cycle Intensity(WCI) is defined as the sum of precipitation and actual evapotranspiration within a landscape unit. It is a widely used metric to quantify the impact of climate change on the global distribution of water resources. WCI in the Pamir Plateau, located at the heart of Asian Water Towers, has received little attention. Understanding this aspect is crucial for assessing the impact of climate change on the hydrological cycle and devising strategies to adapt to these changes. Our study assessed the spatiotemporal variation in WCI on the Pamir Plateau from 1980 to 2019 using the WCI framework. Additionally, we explored the teleconnection mechanisms linking the WCI with the Indian Ocean Dipole Mode Index(DMI), canonical El Ni?o-Southern Oscillation(ENSO), and El Ni?o Modoki(EMI) using the wavelet analysis method. The findings showed that the WCI of the Pamir Plateau experienced a statistically insignificant increase from 1980 to 2019, particularly after 2003. Spatially, the eastern Pamir Plateau WCI increased significantly, whereas the western region showed a non-significant downward trend. This study found that the WCI in the Pamir Plateau is significantly influenced by atmospheric circulation patterns, and the variation in the WCI in the Pamir Plateau is mainly affected by the canonical ENSO, as well as by the coupling effect of canonical ENSO, and EMI. In addition, based on the characteristics of the regional hydrological cycle, we developed water resource management policies targeting flood risks in the northern Pamir Plateau and drought trends in the southwestern region. These insights not only deepen our understanding of changes in terrestrial hydrological cycles and their underlying mechanisms under climate change but also provide important references for water resource management in the mountainous regions of Central Asia.

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The sudden ocean warming and its potential influences on earlyfrozen landfast ice in the Prydz Bay, East Antarctica

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Acta Oceanologica Sinica 2024年第5期43卷 65-77页

作者： Haihan Hu Jiechen Zhao Jingkai Ma Igor Bashmachnikov Natalia Gnatiuk Bo Xu Fengming Hui School of Geospatial Engineering and Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Comprehensive Observation of Polar environment(Sun Yat-sen University) Ministry of EducationZhuhai 519082China Qingdao Innovation and Development Base(centre)of Harbin Engineering University Qingdao 266500China Key Laboratory for Polar Acoustics and Application of Ministry of Education(Harbin Engineering University) Harbin 150001China Key Laboratory of Research on Marine Hazards Forecasting National Marine Environmental Forecasting CentreBeijing 100081China Nansen International environmental and remote sensing centre St.Petersburg 199034Russia Saint Petersburg state University St.Petersburg 199034Russia Antarctic Great Wall Ecology National Observation and Research Station Polar Research Institute of ChinaShanghai 201209China

The ocean conditions beneath the ice cover play a key role in understanding the sea ice mass balance in the polar *** integrated high-frequency ice-ocean observation system,including Acoustic Doppler Velocimeter,Conductivity-Temperature-Depth Sensor,and Sea Ice Mass Balance Array(SIMBA),was deployed in the landfast ice region close to the Chinese Zhongshan Station in Antarctica.A sudden ocean warming of 0.14℃(p<0.01)was observed beneath early-frozen landfast ice,from(−1.60±0.03)℃during April 16-19 to(−1.46±0.07)℃during April 20-23,2021,which is the only significant warming event in the nearly 8-month *** sudden ocean warming brought a double rise in oceanic heat flux,from(21.7±11.1)W/m^(2) during April 16-19 to(44.8±21.3)W/m^(2) during April 20-23,2021,which shifted the original growth phase at the ice bottom,leading to a 2 cm melting,as shown from SIMBA and borehole ***,the slowdown of ice bottom freezing decreased salt rejection,and the daily trend of observed ocean salinity changed from+0.02 d^(-1) during April 16-19,2021 to+0.003 d^(-1) during April 20-23,*** potential reasons are increased air temperature due to the transit cyclones and the weakened vertical ocean mixing due to the tide phase transformation from semi-diurnal to *** high-frequency observations within the ice-ocean boundary layer enhance the comprehensive investigation of the ocean’s influence on ice evolution at a daily scale.

关键词： sudden ocean warming oceanic heat flux landfast ice Zhongshan Station in-situ observation

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Parameterization, sensitivity, and uncertainty of 1-D thermodynamic thin-ice thickness retrieval

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Acta Oceanologica Sinica 2024年第7期43卷 93-111页

作者： Tianyu Zhang Mohammed Shokr Zhida Zhang Fengming Hui Xiao Cheng Zhilun Zhang Jiechen Zhao Chunlei Mi School of Geospatial Engineering and Science Sun Yat-Sen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Comprehensive Observation of Polar environment(Sun Yat-Sen University) Ministry of EducationZhuhai 519082China state Key Laboratory of remote sensing Science College of Global Change and Earth System ScienceBeijing Normal UniversityBeijing 100875China Science and Technology Branch Environment and Climate Change CanadaToronto M3H5T4Canada Qingdao Innovation and Development Base(centre) Harbin Engineering UniversityQingdao 266500China state Key Laboratory of Resources and environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Retrieval of Thin-Ice Thickness(TIT)using thermodynamic modeling is sensitive to the parameterization of the independent variables(coded in the model)and the uncertainty of the measured input *** article examines the deviation of the classical model’s TIT output when using different parameterization schemes and the sensitivity of the output to the ice ***,it estimates the uncertainty of the output in response to the uncertainties of the input *** parameterized independent variables include atmospheric longwave emissivity,air density,specific heat of air,latent heat of ice,conductivity of ice,snow depth,and snow *** input parameters include air temperature,ice surface temperature,and wind *** the independent variables,the results show that the highest deviation is caused by adjusting the parameterization of snow conductivity and depth,followed ice *** sensitivity of the output TIT to ice thickness is highest when using parameterization of ice conductivity,atmospheric emissivity,and snow conductivity and *** retrieved TIT obtained using each parameterization scheme is validated using in situ measurements and satellite-retrieved *** in situ measurements,the uncertainties of the measured air temperature and surface temperature are found to be *** resulting uncertainties of TIT are evaluated using perturbations of the input data selected based on the probability distribution of the measurement *** results show that the overall uncertainty of TIT to air temperature,surface temperature,and wind speed uncertainty is around 0.09 m,0.049 m,and−0.005 m,respectively.

关键词： Arctic sea ice 1-D thermodynamic ice model thin-ice thickness sea ice parameterization

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Land use and land cover changes over a century (1914 2007) in the Neyyar River Basin, kerala: a remote sensing and GIS approach

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International Journal of Digital Earth 2011年第3期4卷 258-270页

作者： R.V.Sheeja Sabu Joseph D.S.Jaya R.S.Baiju kerala state remote sensing and environment centre VikasbhavanThiruvananthapuram 695033KeralaIndia Department of environmental Sciences University of KeralaKariyavattomThiruvananthapuramKeralaIndia centre for Earth Science Studies(CESS) ThiruvananthapuramKeralaIndia

Land use and land cover change,perhaps the most significant anthropogenic disturbance to the environment,mainly due to rapid urbanization/industrialization and large scale agricultural *** this paper,an attempt has been made to appraise land use/land cover changes over a century(19142007)in the Neyyar River Basin(L56 km;Area483.4 km2)in southern keralaa biodiversity hot spot in Peninsular *** this study,digital remote sensing data of the Indian remote sensing satellite series I-D(LISS III,20062007)on 1:50,000 scale,Survey of India(SOI)toposheet of 1914(1:63,360)and 1967(1:50,000)have been utilized to map various land use/land cover *** of different periods have been registered and resampled to similar geographic coordinates using ERDAS Imagine *** most notable changes include decreases in areas of paddy cultivation,mixed crops,scrub lands and evergreen forests,and increases in built-up areas,rubber plantations,dense mixed forests,and water ***,large scale exploitation of flood plain mud and river sand have reached menacing proportions leading to bank caving and cut offs at channel *** of land and water resources forms an important aspect of ecosystem management in the basin.

关键词： remote sensing GIS land use/land cover Neyyar basin kerala

Relative Impacts of Sea Ice Loss and Atmospheric Internal Variability on the Winter Arctic to East Asian Surface Air Temperature Based on Large-Ensemble Simulations with NorESM2

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Advances in Atmospheric Sciences 2024年第8期41卷 1511-1526页

作者： Shengping HE Helge DRANGE Tore FUREVIK Huijun WANG Ke FAN Lise Seland GRAFF Yvan J.ORSOLINI Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5020Norway Nansen environmental and remote sensing Center Bergen 5007Norway Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 211544China Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 511458China School of Atmospheric Science Sun Yat-Sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Norwegian Meteorological Institute Oslo 0313Norway Norwegian Institute for Air Research Kjeller 2007Norway

To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.

关键词： Arctic sea ice loss warm Arctic–cold East Asia atmospheric internal variability large-ensemble simulation NorESM2 PAMIP

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Modeling glacio-hydrological processes in the Himalayas:A review and future perspectives

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Geography and Sustainability 2024年第2期5卷 179-192页

作者： Lei Wang Hu Liu Ranjeet Bhlon Deliang Chen Junshui Long Tenzing C.Sherpa state Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburgS-40530(Box 460)Sweden International centre for Integrated Mountain Development Lalitpur 44700Nepal

The Himalayas and their surrounding areas boast vast glaciers rivaling those in polar regions,supplying vital meltwater to the Indus,Ganges,and Brahmaputra rivers,supporting over a billion downstream inhabitants for drinking,power,and *** changing runoff patterns due to accelerated glacial melt,understanding and projecting glacio-hydrological processes in these basins is *** review assesses the evolution,applications,and key challenges in diverse glacio-hydrology models across the Himalayas,varying in complexities like ablation algorithms,glacier dynamics,ice avalanches,and *** findings indicate higher glacial melt contributions to annual runoff in the Indus compared to the Ganges and Brahmaputra,with anticipated peak melting in the latter basins—having less glacier cover—before the mid-21st century,contrasting with the delayed peak expected in the Indus Basin due to its larger glacier *** modeling studies still have large uncertainties in the simulated runoff components in the Himalayan basins;and the projections of future glacier melt peak time vary at different Himalaya sub-basins under different Coupled Model Intercomparison Project(CMIP)*** also find that the lack of reliable meteorological forcing data(particularly the precipitation errors)is a major source of uncertainty for glacio-hydrological modeling in the Himalayan ***,permafrost degradation compounds these challenges,complicating assessments of future freshwater *** measures include establishing comprehensive in situ observations,innovating remote-sensing technologies(especially for permafrost ice monitoring),and advancing glacio-hydrology models to integrate glacier,snow,and permafrost *** endeavors are crucial for informed policymaking and sustainable resource management in this pivotal,glacier-dependent ecosystem.

关键词： Glacio-hydrology Modeling Himalayas Glacier,snow,and permafrost Sustainable development

Improved Cubemap model for 3D navigation in geo-virtual reality

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International Journal of Digital Earth 2015年第11期8卷 877-900页

作者： Qishen Duan Jianhua Gong Wenhang Li Shen Shen Rong Li state Key Laboratory of remote sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijingChina Zhejiang&CAS Application centre for Geoinformatics ZhejiangChina

Due to advances in rendering techniques and hardware capability,stereoscopic 3D(s3D)visualization is becoming increasingly common in daily ***,this does not change the fact that stereo effects and visual comfort depend greatly on how the related parameters are controlled during the production of the s3D *** geovirtual reality systems,which are important browsers for Digital Earth,the maintenance of these parameters is deeply related to the navigation ***,the navigation method in such systems requires special *** paper presents a new flying method based on a Cubemap *** method defines a Vehicle model and modifies the original Cubemap structure by adding a front view camera during the navigation;it allows the users to fly through a virtual geographic environment with automatic speed control,smooth collision resolution,and dynamic adjustment of the s3D-related parameters.A user test was conducted to compare this new method with the original method based on the Cubemap *** results show that the new method performs better than the former one for it provides a convenient interaction experience with improved stereoscopic effect,and diminishes visual discomfort.

关键词： virtual reality navigation Digital Earth virtual geographic environment

Land cover classification from remote sensing images based on multi-scale fully convolutional network

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Geo-Spatial Information Science 2022年第2期25卷 278-294页

作者： Rui Li Shunyi Zheng Chenxi Duan Libo Wang Ce Zhang School of remote sensing and Information Engineering Wuhan UniversityWuhanChina Faculty of Geo-Information Science and Earth Observation(ITC) University of TwenteEnschedeThe Netherlands The state Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Lancaster environment centre Lancaster UniversityLancasterUK UK centre for Ecology&Hydrology LancasterUK

Although the Convolutional Neural Network(CNN)has shown great potential for land cover classification,the frequently used single-scale convolution kernel limits the scope of informa-tion ***,we propose a Multi-Scale Fully Convolutional Network(MSFCN)with a multi-scale convolutional kernel as well as a Channel Attention Block(CAB)and a Global Pooling Module(GPM)in this paper to exploit discriminative representations from two-dimensional(2D)satellite ***,to explore the ability of the proposed MSFCN for spatio-temporal images,we expand our MSFCN to three-dimension using three-dimensional(3D)CNN,capable of harnessing each land cover category’s time series interac-tion from the reshaped spatio-temporal remote sensing *** verify the effectiveness of the proposed MSFCN,we conduct experiments on two spatial datasets and two spatio-temporal *** proposed MSFCN achieves 60.366%on the WHDLD dataset and 75.127%on the GID dataset in terms of mIoU index while the figures for two spatio-temporal datasets are 87.753%and 77.156%.Extensive comparative experiments and abla-tion studies demonstrate the effectiveness of the proposed MSFCN.

关键词： Spatio-temporal remote sensing images Multi-Scale Fully Convolutional Network land cover classification