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Modeling of Spring Phenology of Boreal Forest by Coupling Machine Learning and Diurnal Temperature Indicators

Chinese geographical Science 2025年第1期35卷 38-54页

作者： DENG Guorong ZHANG Hongyan HONG Ying GUO Xiaoyi YI Zhihua EHSAN BINIYAZ School of Hydraulic Engineering Nanchang Institute of TechnologyNanchang 330099China Key Laboratory of geographical Processes and Ecological Security in Changbai Mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun 130024China Urban remote sensing Application Innovation Center School of Geographical SciencesNortheast Normal UniversityChangchun 130024China School of geographical Sciences Inner Mongolia Normal UniversityHohhot 010022China Landscape Ecology and Geoinformation Science Department of GeographyKiel UniversityKiel 24118Germany

The roles of diurnal temperature in providing heat accumulation and chilling requirements for vegetation spring phenology *** previous studies have established a stronger correlation between leaf onset and diurnal temperature than between leaf onset and average temperature,current research on modeling spring phenology based on diurnal temperature indicators remains *** this study,we confirmed the start of the growing season(SOS)sensitivity to diurnal temperature and average temperature in boreal *** estimation of SOS was carried out by employing K-Nearest Neighbor Regression(KNR-TDN)model,Random Forest Regres-sion(RFR-TDN)model,eXtreme Gradient Boosting(XGB-TDN)model and Light Gradient Boosting Machine model(LightGBM-TDN)driven by diurnal temperature indicators during 1982-2015,and the SOS was projected from 2015 to 2100 based on the Coupled Model Intercomparison Project Phase 6(CMIP6)climate scenario *** sensitivity of boreal forest SOS to daytime temperature is greater than that to average temperature and nighttime *** LightGBM-TDN model perform best across all vegetation types,exhibiting the lowest RMSE and bias compared to the KNR-TDN model,RFR-TDN model and XGB-TDN *** incorporating diurn-al temperature indicators instead of relying only on average temperature indicators to simulate spring phenology,an improvement in the accuracy of the model is ***,the preseason accumulated daytime temperature,daytime temperature and snow cover end date emerged as significant drivers of the SOS simulation in the study *** simulation results based on LightGBM-TDN model exhibit a trend of advancing SOS followed by stabilization under future climate *** study underscores the potential of diurn-al temperature indicators as a viable alternative to average temperature indicators in driving spring phenology models,offering a prom-ising new method for simulating spring phenology.

关键词： spring phenology diurnal temperature machine learning future climate scenarios boreal forest

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On-orbit attitude planning for Earth observation imaging with star-based geometric calibration

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Science China(Technological Sciences) 2025年第2期68卷 243-256页

作者： Di HUANG Zhifu WANG Jianya GONG Haoran JI institute of Aerospace Science and Technology School of Remote Sensing and Information EngineeringWuhan UniversityWuhan 430072China State Key Laboratory of information Engineering in Surveying Mapping and Remote SensingSchool of Remote Sensing and Information EngineeringWuhan UniversityWuhan 430072China National Key Laboratory of Air-based information Perception and Fusion Luoyang 471009China Intelligent Game and Decision Laboratory Beijing 100071China

To improve the quality of remote sensing images,a novel on-orbit attitude planning method for Earth observation imaging with star-based geometric calibration is presented in this *** traditional imaging processes,the proposed method includes both pre-calibration and post-calibration stages to enhance the accuracy of satellite geometric positioning.A multiple-constraint attitude planning algorithm was developed to ensure star-based calibration,wherein the satellite camera and star sensors simultaneously capture the images of *** integration of cameras and multiple star sensors enables effective attitude *** the Earth imaging stage,a fast on-orbit attitude planning algorithm was developed to determine the satellite attitude and the optimal imaging times for ground *** with existing methods,the fast on-orbit attitude planning algorithm can significantly reduce computational time and resource consumption via initial value selection and *** demonstrate the effectiveness of the proposed attitude planning method,which was successfully applied to Wuhan 1 satellite.

关键词： attitude planning Earth observation imaging geometric calibration attitude constraints

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Prospects on mangrove knowledge services in the smart era:From plant atlas to knowledge graphs

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Science China Earth Sciences 2025年第1期68卷 111-127页

作者： Zhi-Wei HOU Wenlong JING Cheng-Zhi QIN Ji YANG Qing XIA Xiaoling YIN Key Laboratory of Guangdong for Utilization of remote sensing and geographical information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou510070China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China State Key Laboratory of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing100049China School of Traffic&Transportation Engineering Changsha University of Science and TechnologyChangsha410114China

Mangroves are crucial to the ecological security of the Earth and human *** management,conservation,and restoration are of great importance and necessitate the support of spatio-temporal information and multidisciplinary knowledge such as biology and *** knowledge services such as plant atlas provide illustrated textual knowledge of ***,this kind of service is oriented to information retrieval and is incapable of effectively mining and utilizing fragmented knowledge from multi-source heterogeneous data,facing the problem of“massive data,rare knowledge”.Knowledge graphs are capable of extracting,organizing,and fusing the knowledge contained in massive data into semantic networks that can be understood and computed by *** provide a solution for the realization of intelligent knowledge *** on the urgent need for mangrove knowledge acquisition,formal representation,and intelligent services,this paper proposes a research prospect on mangrove knowledge graphs and knowledge *** first analyze the similarities and differences between various domain-specific concepts of *** this basis,we define the mangrove knowledge graph as a large-scale knowledge base that integrates multi-disciplinary knowledge and spatio-temporal information with mangrove ecosystems as the ***,we propose a research framework for mangrove knowledge services that can realize the transformation from multi-modal data to intelligent knowledge services,including multiple research levels such as ubiquitous data sensing and aggregation,knowledge organization and graph construction,and intelligent mangrove knowledge ***,the methods and workflow for constructing mangrove knowledge graphs are ***,we discuss the challenges and possible future directions of mangrove knowledge services in the smart era,including the construction of a mangrove knowledge system that integrates the domain-specific charac

关键词： Mangrove Tupu Knowledge graph Multi-modal Knowledge service

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Simulations of GaoFen-5 Directional Polarimetric Camera(DPC) Observations Using the Advanced Vector Discrete Ordinate Radiative Transfer Model

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Advances in Atmospheric Sciences 2025年第3期42卷 486-500页

作者： Yuchen XIE Ziqiang ZHU Fuzhong WENG Zhengqiang LI Xiuzhen HAN School of remote sensing&Geomatics Engineering Nanjing University of Information Science&TechnologyNanjing 210044China Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China Environmental Protection Key Laboratory of Satellite remote sensing&Key Laboratory of remote sensing and Digital Earth Aerospace Information Research InstituteChinese Academy of Sciences.Beijing 100101China National Satellite Meteorological Center China Meteorological AdministrationBeijing 100081China

In recent years,polarization remote sensing has garnered increasing attention,particularly within the realm of *** accurately simulate polarization information,the vector discrete-ordinate radiative transfer(VDISORT)model developed earlier by the community is further enhanced to an advanced version(referred to as A-VDISORT)through an improved ocean surface *** Fresnel reflection matrix,which includes wind-generated roughness and shading effects,is served by an ocean bidirectional reflection distribution function(BRDF).The simulation from AVDISORT is compared with SCIATRAN for a Rayleigh scattering atmosphere,and the influence of water-leaving radiance is analyzed by the PSTAR(Polarized System for Transfer of Atmospheric Radiation) *** GaoFen-5 Directional Polarimetric Camera(DPC) observations with polarization and multi-angle information,clear-sky pixel recognition over the ocean is first carried *** DPC reflectance of clear conditions is normalized and compared with the *** is shown that A-VDISORT has a high simulation accuracy with a bias of –*** difference between simulation and observation exhibits a standard normal probability distribution function.

关键词： vector radiative transfer equation A-VDISORT ocean BRDF GF-5 DPC

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Human activities rather than climate change dominate the growth of carbon fluxes in the Hexi Corridor oasis area, China

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Journal of geographical Sciences 2025年第2期35卷 252-277页

作者： ZHOU Xuqiang WANG Xufeng REN Zhiguo ZHANG Yang TAN Junlei NAWAZ Zain Key Laboratory of Cryospheric Science and Frozen Soil Engineering Key Laboratory of Remote Sensing of Gansu Province Heihe Remote Sensing Experimental Research Station Northwest Institute of Eco-Environment and Resources CAS University of Chinese Academy of Sciences Department of Geography Government College University Faisalabad

Carbon fluxes are essential indicators assessing vegetation carbon cycle ***,the extent and mechanisms by which climate change and human activities influence the spatiotemporal dynamics of carbon fluxes in arid oasis and non-oasis area remains ***,we assessed and predicted the future effects of climate change and human activities on carbon fluxes in the Hexi *** results showed that the annual average gross primary productivity （GPP）,net ecosystem productivity （NEP）,and ecosystem respiration （Reco） in the Hexi Corridor oasis increased by 263.91 g C·m–2·yr–1,118.45 g C·m–2·yr–1and 122.46 g C·m–2·yr–1,respectively,due to the expansion of the oasis area by 3424.84 km2caused by human activities from 2000 to *** oasis and non-oasis arid ecosystems in the Hexi Corridor acted as carbon *** to the non-oasis area,the carbon fluxes contributions of oasis area increased,ranging from 10.21%to 13.99%for GPP,8.50%to11.68%for NEP,and 13.34%to 17.13%for *** contribution of the carbon flux from the oasis expansion area to the total carbon flux change in the Hexi Corridor was 30.96%(7.09 Tg C yr–1) for GPP,29.57%(3.39 Tg C yr–1) for NEP and 32.40%(3.58 Tg C yr–1) for *** changes in carbon fluxes in the oasis area were mainly attributed to human activities （oasis expansion） and temperature,whereas non-oasis area was mainly due to climate ***,the future increasing trends were observed for GPP （64.99%）,NEP（66.29%） and Reco （82.08%） in the Hexi *** study provides new insights into the regulatory mechanisms of carbon cycle in the arid oasis and non-oasis area.

关键词： carbon fluxes climate change Hexi Corridor oasis human activities random forest

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Tracking the Moisture Sources of an Extreme Precipitation Event in Shandong,China in July 2007:A Computational Analysis

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Journal of Meteorological Research 2014年第4期28卷 634-644页

作者：张弛李琦 institute of remote sensing and geographical information systems Peking University

This paper utilizes a modified Water Accounting Model （WAM） to track the moisture sources of an extreme precipitation event in Shandong during 18-20 July 2007. It is found that different methods in dealing with the residual of the water budget always produce different results in moisture recycling calculations. In addition, results from the backward tracking without the residual are in complete agreement with those from the forward tracking with the residual, and vice versa, implying a mathematical consistency. We thus analyze and derive the conditions under which the two tracking approaches equate with each other. We applied the backward tracking to the Shandong extreme rainfall case and obtained quantitative estimates of moisture contributions of three selected regions away from the rainfall area. The results indicate that the spatial pattern rather than numerical value of the recycling moisture is more reliable in tracking the moisture sources. The moisture of this Shandong rainfall event comes mostly from the nearby upwind area in Southwest China, which is of the terrestrial origin; while the moisture originating from the neighboring West Pacific contributes little to this event.

关键词： bulk model precipitation recycling moisture recycling backward tracking

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Laser image refractive index sensor based on the combination of a coreless optical fiber and a digital camera

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Optoelectronics Letters 2025年第2期21卷 65-68页

作者： GUO Jingzhong LAN Feng CHEN Xiang LIU Haifeng Xi’an institute of Space Radio Technology Xi’an 710100China Key Laboratory of Optoelectronic Sensor and sensing Network Technology College of Electronic Information and Optical EngineeringNankai UniversityTianjin 300350China

As a laser passes through a scattering medium,the light interacts with the irregular reflections within the medium,resulting in light scattering and the formation of *** this paper,an image sensor based on the combination of a coreless optical fiber and a digital camera is proposed for liquid refractive index sensing *** coreless fiber is used as a sensing unit,and the change in the speckle pattern is measured using the digital correlation method to detect the magnitude of the liquid's refractive *** experimental results indicate that the laser image sensing technique is capable of effectively distinguishing liquid samples with refractive indices ranging from 1.332 8 to1.390 8,with a sensing sensitivity of-1.306 ***,the laser image sensing technique,with its advantages of high experimental reproducibility,simple system design,remote over-control,holds great research significance and potential application in laser communication and sensor integration.

关键词： fiber scattering optical

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A semantic geographical knowledge wiki system mashed up with Google Maps

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Science China(Technological Sciences) 2010年第S1期53卷 52-60页

作者： GAO Yong,GAO Song,LI RunQiang & LIU Yuinstitute of remote sensing and geographical information systems,Peking University,Beijing 100871,China 1. institute of remote sensing and geographical information systems Peking University Beijing 100871 China

A wiki system is a typical Web 2.0 application that provides a bi-directional platform for users to collaborate and share much useful information ***,computers cannot well understand the wiki pages in plain *** user-generated geographical content via wiki systems cannot be manipulated properly and efficiently unless the geographical semantics is explicitly *** this paper,a geographical semantic wiki system,Geo-Wiki,is introduced to solve this ***-Wiki is a semantic geographical knowledge-sharing web system based on geographical ontologies so that computers can parse and storage the multi-source geographical ***,Geo-Wiki mashed up with map services enriches the representation and helps users to find spatial distribution patterns,and thus can serve geospatial decision-making by customizing the Google Maps APIs.

关键词： geo-ontology semantic wiki mashup Google Maps

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Core or edge? Revisiting GIScience from the geography-discipline perspective

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Science China Earth Sciences 2022年第2期65卷 387-390页

作者： Yu LIU institute of remote sensing and geographical information systems School of Earth and Space SciencesPeking UniversityBeijing 100871China

As an inter-disciplinary area between geography and computer sciences, geographical information science(GIScience) inherits the spatial analysis tradition of the former. Together with other branches of information geography, it seeks the balance between universality and particularity of geographical laws by combining methods from neighboring disciplines(such as big data and artificial intelligence) with the special nature of geographical spaces. Meanwhile, at the core position of the geography discipline, GIScience makes geography stronger from two directions: "strengthening the theoretical foundation" and "improving technology and promoting the practical applications".

关键词： geographical information science information geography Geography Characteristics of geographical spaces

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Framework and development of digital China

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Science China(Technological Sciences) 2008年第S1期51卷 1-5页

作者： WU Lun & TONG QingXi institute of remote sensing and geographical information systems,Peking University,Beijing 100871,China 1. institute of remote sensing and geographical information systems Peking University Beijing 100871 China

Digital China (DC) has recently drawn much attention. It is a strategic project for China in response to the challenge of sustainable development of population,re-source,and environment. Intending to establish the national information infra-structure (NⅡ),the DC project forms a solid foundation for Chinese informatization. In such an NⅡ,multi-sourced spatial data are integrated. They focus on various themes and have different space and time features. Based on the NⅡ,numerous applications and services can be developed so that spatial information will benefit everyone. Since lots of organizations,such as governments,universities,and en-terprises,are involved in the implementation of DC,the DC project will significantly prompt the relevant scientific research as well as economic progress in China.

关键词： Digital Earth Digital China spatial information sciences and technology

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