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Spatial Characteristics of Soil Organic Carbon Storage in China's Croplands

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Pedosphere 2005年第4期15卷 417-423页

作者： WANG shao-Qiang YU Gui-Rui ZHAO Qian-Jun NIU Dong CheN Qing-Mei WU Zhi-Feng institute of Geographic sciences and natural resources {4. Beijing 10010 （China）. Guangdong institute of Eco-Environment and Soil Science Guangzhou 510650 （China）

The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 154. typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.

关键词： carbon storage cropland soil organic carbon spatial characteristics

Developmetn stage threshold of watershed Landforms in Loess Plateau and separation of erosion mechanism

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Journal of geographical sciences 2002年第1期12卷 81-90页

作者： LU Zhong-chen1, CheN shao-feng2,YUAN Bao-yin3,CheN Hao4.(1.Eco-Environment {4. Center,CAS,beijing 100085,China 2.institute of Policy andManagement Science,CAS,beijing 100080,China 3.institute of Geology,CAS,beijing1000029,China 4.institute of Geograp

Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by *** in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.

关键词： landform development stage hypsometric analysis method integral erosion value natural erosion artificial accelerating erosion

Flooding 1990s along the Yangtze River, has it concern of global warming?

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Journal of geographical sciences 2001年第1期11卷 43-52页

作者： GONG Dao-yi1, ZHU Jin-hong2, WANG shao-wu2 (1. Key Laboratory of Environmental Change and natural Disaster, institute of resources Science, {4. Normal University, {4. 100875, China 2. Department of Geophysics, Peking University, {4. 100871, Key Laboratory of Environmental Change and natural Disaster Institute of Resources Science Beijing Normal University Beijing China Department of Geophysics Peking University Beijing China

There were a series of severe floods along the middle to lower reaches of the Yangtze River (Changjiang River) in China during the 1990s. The extensive summer (June, July and August) precipitation is mostly responsible for the flooding. The summer rainfall in the 1980s and the 1990s is much higher than that in the previous 3 decades. The means for 1990–1999 is +87.62 mm above normal, marked the 1990s the wettest decade since the 1950s. Six stations with a time span of 1880–1999 are selected to establish century-long rainfall series. This series also shows that the 1990s is the wettest decade during the last 120 years. In the wettest 12 years, four occurred in the 1990s (1991, 1996, 1998 and 1999). Both global and China’s temperature show there is a relative lower air temperature during the 1960–1970s, and a rapid warming in the 1980–1990s. Comparisons of rainfall between 1960–1979 and 1980–1999 show there are dramatic changes. In the cold period 1960–1979, the summer rainfall along the Yangtze River is 3.8 % to 4.7 % below the normal, during the warm period 1980–1999, over 8.4 % to 18.2 % of summer rainfall occurs. Over the whole eastern China, the summer rainfall shows opposite spatial patterns from the 1960–1970s to 1980–1990s. The consistent trend toward more rainfall with global warming is also presented by the greenhouse scenario modeling. A millennial Drought/flood Index for the middle to lower reaches of the Yangtze River showed that although the surplus summer rainfall in the 1990s is the severest during the past 150 years, it is not outstanding in the context of past millennium. Power spectra of the Drought/flood Index show significant interdecadal periods at 33.3 and 11.8 years. Thus, both the natural interdecadal variations and the global warming may play important roles in the frequent floods witnessed during the last two decades.

关键词： summer rainfall Yangtze River global warming interdecadal variation

2008年春季中国南方冰雪冻害林木物理折损典型样带分析

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山地学报 2009年第2期27卷 177-187页

作者：邵全琴黄麟刘纪远匡文惠李佳中国科学院地理科学与资源研究所

2008年春季我国南方发生了特大冰雪灾害,林木损害严重。选择江西省井冈山-吉泰盆地-于山山脉-武夷山支脉样带作为研究区,两次进行野外调查,结合收集的数据,进行综合分析,取得结论包括:(1)在研究样带内人工林的损毁程度为湿地松林>马尾松... 详细信息

2008年春季我国南方发生了特大冰雪灾害,林木损害严重。选择江西省井冈山-吉泰盆地-于山山脉-武夷山支脉样带作为研究区,两次进行野外调查,结合收集的数据,进行综合分析,取得结论包括:(1)在研究样带内人工林的损毁程度为湿地松林>马尾松林>混交人工林>杉木林,在受损样本中湿地松林的实际受损比例高达61.3%,其中不可自然恢复折损实际比例达4..2%,相对比例达70.4.,主要是因为湿地松是美国南部地区外来引进种,生长块、材质疏松,而且割脂活动较强;马尾松为乡土造林先锋树种,材质较为坚硬,但受割脂活动影响,在受损样本中实际受损受损比例也高达52.5%,其中不可自然恢复折损实际比例达31.8%,相对比例达60.9%;杉木是本地树种,实际受损比例4.%,其中不可自然恢复受损实际仅14.9%,相对比例也仅32.5%,低于混交人工林。(2)调查样带自西向东,西部井冈山地区常绿阔叶林受损程度最轻,分布在700m左右的人工柳杉林受损严重,杉木林分布在700m以下的受损程度较轻,而分布在900m以上的则相对严重;中部吉泰盆地受损调查样点中,分布在低海拔的湿地松林和马尾松林,因割脂活动受损程度严重,杉木林受损最轻,长期封育的天然次生林落叶阔叶林,由于藤本植物的缠绕,导致大量冰挂积雪,受损十分严重;东部兴国和宁都县,分布在4.0m以下的人工飞播马尾松因个体小基本未受损,分布在4.0m以上的1960年代人工种植马尾松,因割脂活动,受损严重;而分布在500～900m的杉木林受损程度较轻。

关键词：冰雪冻害林木物理折损典型样带实际受损比例

Advancing flood susceptibility modeling using stacking ensemble machine learning: A multi-model approach

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Journal of geographical sciences 2024年第8期34卷 1513-1536页

作者： YANG Huilin YAO Rui DONG Linyao SUN Peng ZHANG Qiang WEI Yongqiang SUN shao AGHAKOUCHAK Amir School of Geography and Tourism Anhui Normal UniversityWuhu 241002AnhuiChina Changjiang River Scientific research institute Wuhan 430015China Advanced Interdisciplinary institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087GuangdongChina Hunan institute of Water resources and Hydropower research Changsha 410007China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Department of Civil and Environmental Engineering University of California IrvineIrvineCA 92697USA

Flood susceptibility modeling is crucial for rapid flood forecasting, disaster reduction strategies, evacuation planning, and decision-making. Machine learning(ML) models have proven to be effective tools for assessing flood susceptibility. However, most previous studies have focused on individual models or comparative performance, underscoring the unique strengths and weaknesses of each model. In this study, we propose a stacking ensemble learning algorithm that harnesses the strengths of a diverse range of machine learning models. The findings reveal the following:(1) The stacking ensemble learning, using RF-XGBCB-LR model, significantly enhances flood susceptibility simulation.(2) In addition to rainfall,key flood drivers in the study area include NDVI, and impervious surfaces. Over 4.% of the study area, primarily in the northeast and southeast, exhibits high flood susceptibility, with higher risks for populations compared to cropland.(3) In the northeast of the study area,heavy precipitation, low terrain, and NDVI values are key indicators contributing to high flood susceptibility, while long-duration precipitation, mountainous topography, and upper reach vegetation are the main drivers in the southeast. This study underscores the effectiveness of ML, particularly ensemble learning, in flood modeling. It identifies vulnerable areas and contributes to improved flood risk management.

关键词： flood susceptibility assessment machine learning stacking ensemble learning flood drivers XiangjiangRiverBasin

High-resolution reconstruction of April-September precipitation and major extreme droughts in China over the past∼530 years

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Science Bulletin 2024年第17期69卷 2756-2764页

作者： Yongxiang Zhang Hongli Wang xuemei shao Hongbin Liu Haifeng Zhu Lily Wang Eryuan Liang Zhixin Hao Xiuqi Fang Qibin Zhang Jinjian Li Xinghe Shi Yujiang Yuan Feng Chen Tongwen Zhang Ruibo Zhang Huaming Shang Jianfeng Peng National Climate Centre China Meteorological AdministrationBeijing 100081China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China beijing New Epoch School the Administrative Bureau of Chinese Academy of SciencesBeijing 100086China University of chinese academy of sciences Beijing 100049China Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China CAS Center for Excellence in Tibetan Plateau Earth sciences Beijing 100101China Faculty of geographical Science Beijing Normal UniversityBeijing 100875China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China School of Atmospheric sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan ProvinceChengdu University of Information TechnologyChengdu 610225China Qinghai Climate Centre Xining 810001 China Key Laboratory of Tree-Ring Physical and Chemical research of China Meteorological Administration Key Laboratory of Tree-Ring Ecology of Xinjiang Uygur Autonomous RegionInstitute of Desert MeteorologyChina Meteorological AdministrationUrumqi 830002China Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security Institute of International Rivers and Eco-SecurityYunnan UniversityKunming 650000China College of Geography and Environmental Science Henan UniversityKaifeng 475004China

Extreme drought events have increased,causing serious losses and damage to the social economy under current warming ***,short-term meteorological data limit our understanding and projection of these *** the accumulation of proxy data,especially tree-ring data,large-scale precipitation field reconstruction has provided opportunities to explore underlying mechanisms *** point-by-point regression,we reconstructed the April-September precipitation field in China for the past~530 years on the basis of 590 proxy records,including 4.0 tree-ring width chronologies and 120 drought/flood *** regression models explained average 50%of the variance in *** the statistical test on calibration and verification,our models passed the significance level that assured reconstruction *** reconstruction data performed well,showing consistency and better quality than previously reported *** first three leading modes of variability in the reconstruction revealed the main distribution modes of precipitation over ***/drought and extremely wet/drought years accounted for 12.81%/10.92%(68 years/58 years)and 1.69%/3.20%(9 years/17 years)of the past~530 years in China,*** extreme drought events can be identified explicitly in our *** detailed features of the Chongzhen Great Drought(1637-164.),the Wanli Great Drought(1585-1590),and the Ding-Wu Great Famine(1874.1879),indicated the existence of potentially different underlying mechanisms that need further *** further improvements can be made for remote uninhabited areas and large deserts,our gridded reconstruction of April-September precipitation in China over the past~530 years can provide a solid database for studies on the attribution of climate change and the mechanism of extreme drought events.

关键词： Precipitation reconstruction Tree rings Historical documents Precipitation variability Extreme droughts

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土地调查监测一体化电子作业平台设计

湖南科技大学学报（自然科学版） 2004年第2期19卷 74-76页

作者：诸云强张述升朱少霞中国科学院地理科学与资源研究所北京100101 北京地星伟业数码有限公司北京100080 首都师范大学资源环境与旅游学院北京100037

根据土地调查监测的业务流程,设计实现了土地调查监测一体化电子作业平台.平台将外业数据采集、空间数据管理和信息发布等功能集成为一体,基本涵盖了土地调查监测的全过程.从根本上解决了传统土地调查监测产品间通讯困难、集成度不高、... 详细信息

根据土地调查监测的业务流程,设计实现了土地调查监测一体化电子作业平台.平台将外业数据采集、空间数据管理和信息发布等功能集成为一体,基本涵盖了土地调查监测的全过程.从根本上解决了传统土地调查监测产品间通讯困难、集成度不高、专业程度低等问题.图2,参9.

关键词：土地调查监测一体化平台电子作业设计中国

Standardization of Qilian Juniper ring-width series in the eastern margin of the Qaidam Basin

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Journal of geographical sciences 2007年第2期17卷 175-186页

作者： XU Yan shao xuemei institute of Geographic sciences and natural resources {4. CAS Beijing 100101 China institute of Tibetan Plateau research CAS Beijing 100085 China

Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper （Sabina przewalskii Kom.） tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve （TGC）. The samples that contained the complete pith and reached to the growing culmination around the 4.th-60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth （IRG） was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.

关键词： the Qaidam Basin Qilian juniper tree-ring width growth trend

Reconstruction of summer temperature variation from maximum density of alpine pine during 1917-2002 for west Sichuan Plateau, China

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Journal of geographical sciences 2008年第2期18卷 201-210页

作者： WU Pu WANG Lily shao xuemei institute of Geographic sciences and natural resources {4. CAS Beijing 100101 China

Having analyzed the tree ring width and maximum latewood density of Pinus densata from west Sichuan, we obtained different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded princi- pally to the precipitation in current May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected summer temperature （June-September）. According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of reconstruction is 51% （F=52.099, p〈0.0001）. In the reconstruction series： before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, this trend was in accordance with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead of time, indicating that the Tibetan Plateau was more sensitive to temperature change. There was an evident summer warming signal after 1983. Although the last 100-year running average of summer temperature in the 1990s was the maximum, the running average of the early 1990s was below the average line and it was cold summer, but summer drought occurred in the late 1990s.

关键词： west Sichuan (province) plateau tree ring summer temperature