Method development for estimating soil organic carbon content in an alpine region using soil moisture data     

Qi LUO  Kun YANG  Yingying CHEN  Xu ZHOU 《中国科学:地球科学(英文版)》2020,63(4):591-601

The high soil organic carbon(SOC) content in alpine meadow can significantly change soil hydrothermal properties and further affect the soil temperature and moisture as well as the surface water and energy budget. Therefore, this study first introduces a parameterization scheme to describe the effect of SOC content on soil hydraulic and thermal parameters in a land surface model(LSM), and then the SOC content is estimated by minimizing the difference between observed and simulated surface-layer soil moisture. The accuracy of the estimated SOC content was evaluated using in situ observation data at a soil moisture and temperature-measuring network in Naqu, central Tibetan Plateau. Sensitivity experiments show that the optimum time window for stabilizing the estimation results cannot be shorter than three years. In the experimental area, the estimated SOC content can generally reflect the spatial distribution of the measurements, with a root mean square error of 0.099 m^3 m^-3, a mean bias of 0.043 m^3 m^-3, and a correlation coefficient of 0.695. The estimated SOC content is not sensitive to the temporal frequency of the soil moisture data input. Even if the temporal frequency is as low as that of current soil moisture products derived from passive microwave satellites, the estimation result is still stable. Therefore, by combining a high-quality satellite soil moisture product and a parameter optimization method, it is possible to obtain grid-scale effective parameter values, such as SOC content,for an LSM and improve the simulation ability of the LSM.  相似文献   

不动产测量成果构建地理实体的方法研究     

王化娟  张新长  贠法长 《测绘科学》2023,(3):16-24

针对建筑物实体的快速融合构建模式，实现场景数据的结构化和语义化，是目前自然资源部和各新型基础测绘试点城市研究的重要内容。该文提出了一种基于不动产测量成果构建建筑物房屋、层、户实体的方法。以不动产测量图元为基准，基于业务规则对图元进行定性描述并编码，并变换成竣工验收测量图元，解决了在构建实体数据时提取不同专题要素间数据的关联关系问题；通过解析图元编码，可快速识别图元的语义，实现对构成实体的图元要素快速提取和按规则高效融合。实验结果表明：该方法不仅有效解决专业测绘数据自动适配组装基础测绘建筑物实体数据的问题，同时以不动产登记业务和工程项目竣工验收业务为驱动，解决了数据更新及时、动态持续的问题。  相似文献   

江苏吕四海岸沉积动力特征及侵蚀过程   总被引：1，自引：0，他引：1  

哈长伟  陈沈良  张文祥  谷国传 《海洋通报》2009,28(3)

海岸侵蚀与水动力之间有着密切的关系.基于现场调查和资料收集,探讨了吕四海岸地貌、水动力、泥沙运动以及沉积与动力之间的响应.研究结果表明,风浪和潮流是塑造吕四海岸的主要动力.风浪年内变化按向岸风频率可分为高频期(10 月至翌年 1月)、转频期(2 月、3 月和 9 月)和低频期(4～8月)三个时期.风浪高频期,潮滩冲蚀,物质粗化;低频期,潮滩淤积,物质细化;转频期,时冲时淤,动态稳定.潮流作用主要表现为输沙淤滩和侧蚀滩脚.在风浪高频期,滩脚同时受到风浪冲蚀和潮流侧蚀,向岸后退,使吕四岸段成为隐性侵蚀型海岸.岸滩塑造对沉积动力响应显著,东部处于滨岸环境,在潮流和风浪的作用下,沉积物由岸向海变粗;西部还受径流影响,处于滨岸-河口环境,物质由岸向海变细.在水动力要素中,风浪是导致岸滩侵蚀的主控动力,而潮流则是近岸泥沙进行滩槽滩槽交换和循环输运的输运动力.  相似文献   

The Biomarkers in the Mesoproterozoic Organic-rich Rocks of North China Craton: Implication for the Precursor and Preservation of Organism in the Prokaryotic Realm     

MA Sihong  ZHANG Shuichang  SU Jin  WANG Xiaomei  HE Kun  FANG Yu  MI Jingkui 《《地质学报》英文版》2022,96(1):293-308

Mesoproterozoic marine organic-rich rocks are widely distributed in the North China Craton,include the Gaoyuzhuang(GYZ),the Hongshuizhuang(HSZ),and the Xiamaling(XML)formations.According to the T;value and isomerisation ratio of C;homohopanes,the XML,HSZ,and GYZ samples were in low mature,mature and high mature stage,respectively.Biomarker distribution in extractable organic matter(EOM)of three Mesoproterozoic organic-rock samples in different maturity were analysed to reveal the organic precursor and preservation pathway of in the Mesoproterozoic Combined with gold-tube pyrolysates of three Mesoproterozoic samples,it could further illuminate the chemical composition of Mesoproterozoic kerogen,given excluding.The results indicated that the three formations were all deposited under reducing condition and their organic precursors mainly were some aquatic organisms.High content of rearranged hopanes was detected in EOM of XML and HSZ samples,whereas they were relatively low in the high mature GYZ sample.Contrast to that in EOM,the relative concentration of rearranged hopanes sharply decreased in the gold-tube pyrolysates of the XML kerogen,then slightly increased but was still significantly lower than the EOM of XML sample,which indicated that catalysis of clay minerals in the early diagenesis only changed the chemical composition of the unstable functional groups of the kerogen during the preservation.Due to the thriving heterotrophic microbes and low sink rate of particulate organic matter during the Mesoproterozoic,primary producers suffered extensive degradation during sinking process,only some resistant biopolymers lacking of lipid compounds survived from heterotrophic degradation,while heterotrophic microbes contained more proportion of organic precursors.Abundant pristane(Pr)and phytane(Ph)were only released in high mature stage because of the protection of the macromolecular structure of resistant biopolymers which prevented biomarkers from being altered by the thermal stress.The absence of 13α(n-alkyl)-tricyclic terpanes in the high matured hydrocarbon products also indicated the different precursors between different parts of Mesoproterozoic kerogen.The evolution of the biomarker composition and content of Mesoproterozoic kerogen showed some special characteristics differing from those of Phanerozoic kerogen.The total concentrations of hopanes displayed with an order of low mature stage>high mature stage>mature stage.Relative content of rearranged hopanes in the hydrocarbon generated in high mature stage was significantly lower than that in the low maturity stage.The ratios of Pr/n-C₁₇ and Ph/n-C₁₈ increased with thermal maturity,and the ratio of nC_21-/nC₂₂₊ decreased in the high maturity stage,thus displaying another order of mature stage>high maturity stage>low maturity stage.The unique preservation pathway of Mesoproterozoic organisms was attributed to the special evolution characteristics of biomarker distributions,which should be considered in the Mesoproterozoic marine environment and biological studies.  相似文献   

The Electromagnetic Exploration Experimentation of Nihe Porphyry Iron Ore in Anhui     

ZHANG Kun  YAN Jiayong 《地质学报》2014,88(Z2):1328-1328

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Discovery and Genesis Discussion on A Early-Cambrian Large-Scale Vanadium Deposit from Eastern Guizhou, China          下载免费PDF全文

WEI Huairui  YANG Ruidong  WU Zicheng  GAO Junbo  LIU Kun  WANG Xing 《地质学报》2014,88(Z2):264-265

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Inferring Human-elephant Coexistence Based on Characteristics of Human-elephant Interactions in Nangunhe of Yunnan,China     

WANG Jiahui  CHEN Ying  SUN Yakuan  LYU Zhuoluo  SHI Kun 《中国地理科学(英文版)》2023,(2):363-376

Human-wildlife conflict(HWC) negatively impacts both humans and wildlife. Attitudes of local residents have been critical in promoting wildlife conservation. It is therefore necessary to understand the characteristics of HWC and identify influential factors on attitudes towards conservation to implement conservation strategies efficiently. This research focused on features of human-elephant interactions, while attitudes and values regarding the small population of Asian elephants(Elephas maximus...  相似文献   

基于随机森林-特征递归消除模型的可解释性缓丘岭谷地貌滑坡易发性评价     

孙德亮  陈丹璐  密长林  陈星宇  密士文  李晓琴 《地质力学学报》2023,(2):202-219

研究旨在基于随机森林-特征递归消除模型，通过SHAP算法(SHapley Additive exPlanation, SHAP)与部分依赖图(Partial Dependence Plot, PDP)对缓丘岭谷地貌区域进行滑坡易发性评价与内部机制解释，以期为地质灾害防治研究提供参考。利用优化随机森林算法对典型缓丘岭谷地区滑坡易发性进行研究，建立缓丘岭谷滑坡易发性评价模型；利用特征递归消除算法剔除噪声因子，选取地形地貌、地质构造、环境条件、人类活动5个类型16个因子构建重庆合川区滑坡致灾因子数据库；结合合川区754个历史滑坡点，利用随机森林算法对因子重要性进行排序，并根据专家经验法对研究区的滑坡易发性进行划分，将研究区的滑坡易发性分为极低、低、中、高、极高5个等级；应用部分依赖图对合川区滑坡发生影响大的因子进行解释和SHAP算法对个体滑坡进行局部解释。结果表明：与原模型相比，随机森林-特征递归消除模型测试集AUC值提高了0.019,证明了特征递归消除算法的有效性；训练集以及测试集的AUC值分别为0.769、0.755,具有较高的预测精度；缓丘缓坡地区在起伏较大地区滑坡密度较大，历史滑坡多...  相似文献   

Geological, Isotopic and Geochronological Constraints on Hetaoping Distal Skarn-Type Zn-Pb-Ag-Cu Deposits in Baoshan Palaeozoic Massif, SW China     

XUE Chuandong  WEI Aiying  LIAO Cheng  WANG Jianrong  HAN Yanwei  LI Jing  XIANG Kun 《地质学报》2014,88(Z2):937-939

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