Elevated sedimentation in lake records linked to agricultural activities in the Ishikari River floodplain,northern Japan     

Young Sang Ahn  Futoshi Nakamura  Toshikazu Kizuka  Yugo Nakamura 《地球表面变化过程与地形》2009,34(12):1650-1660

The purpose of this study was to examine the historical change in sedimentation rates in lakes that have been impacted by river regulation and agricultural activities in the Ishikari River floodplain. We dated sediment cores using caesium‐137 (¹³⁷Cs) dating and tephrochronology, and we estimated sediment sources from ¹³⁷Cs concentrations in the topsoil of representative land covers. We found that, between 1739 and 1963, the distance between the lake and the main river channel and whether or not the lake was connected to the river affected the sedimentation rates. After 1963, agricultural drainage systems were established in the Ishikari River floodplain. The average sedimentation rate before and after the construction of drainage ditches varied between 1–66 and 87–301 mg cm^–2 a^–1, respectively. The increase in the sedimentation rate after 1963 was caused by the construction of a number of drainage networks, as well as extensive cultivation activity and/or fragmentation of the swamp buffers surrounding the lakes. The ¹³⁷Cs activities at the surfaces of the lake as well as the catchment‐derived ¹³⁷Cs contributions and ¹³⁷Cs inventory in the lake profiles were used to examine the sediment influx from the various drainage areas after the establishment of the drainage system. Our results indicate that the majority of the lake sediments were derived from cultivated areas, and therefore the catchment‐derived ¹³⁷Cs contribution in the lakes was strongly correlated with the sedimentation rate. The ¹³⁷Cs inventory across all of the lake profiles was also significantly greater than the atmospheric fallout. We identified a negative correlation between the ¹³⁷Cs lake profile inventory and the sedimentation rate. This is because the sediment originating from the drainage areas contained low ¹³⁷Cs concentrations, which diluted the overall concentration of ¹³⁷Cs in the lake sediment. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

基于经济模拟的中国能源消费与碳排放高峰预测   总被引：42，自引：2，他引：40  

朱永彬  王铮  庞丽  王丽娟  邹秀萍 《地理学报》2009,64(8):935-944

能源消费所产生的碳排放是经济发展过程中不可避免的副产品,而且碳排放在大气中的积累会使全球气候不断变暖,因此经济增长与碳排放之间的关系一直是学术界关注的焦点。传统的基于EKC曲线的经济计量学方法一般是对经济与排放历史数据的相关关系研究,不能很好地反映二者之间的动力学机制。为此本文在内生经济增长模型Moon-Sonn基础上进行改进,首先从理论上得到了最优经济增长率与能源强度之间存在倒U曲线关系的必要条件,即能源的产出弹性小于0.5;接着将投入产出分析得到的反映技术进步下的能源强度代入模型,对中国未来经济增长路径进行了预测,同时得到了最优增长路径下的能源消费走势,进而通过对能源消费结构和不同能源品种的碳排放系数的预测和估计,以及对分品种能源碳排放的汇总计算得到了中国未来能源消费所产生的总的碳排放走势。结果显示,在当前技术进步速率下,我国分别在2043年和2040年达到能源消费高峰和碳排放高峰。此外,本文对能源强度不同下降速率对能源消费高峰的影响进行模拟发现,当降速为4.5%~5%时,能源高峰将出现在2040年前,此时的人均GDP为10万元左右,与OECD国家的高峰时收入一致;而且分3种情景模拟了可再生能源替代政策对...  相似文献   

Late Quaternary lake response to climate change and anthropogenic impact: biomarker evidence from Lake Constance sediments     

Sabine Hanisch  Martin Wessels  Frank Niessen  Antje Schwalb 《Journal of Paleolimnology》2009,41(3):393-406

This study used organic matter in oligotrophic Lake Constance (southern Germany) to reconstruct lake environment and to disentangle the multiple factors, such as climate change and human impacts, which influence sedimentation in large lakes. A sediment core from Upper Lake Constance, which represents 16,000 years of Late Glacial and Holocene lake history, was analysed for organic biomarkers, hydrogen index and elements calcium, strontium, and magnesium. Magnetic susceptibility was measured to establish a high-resolution stratigraphic framework for the core and to obtain further information about changes with respect to relative allochthonous versus autochthonous sedimentation. Dinosterol—a biomarker for dinoflagellates—and calcium have low concentrations in Younger Dryas sediments and consistently high concentrations between 10,500 and 7,000 cal. years BP. These variations are attributed to changes in lake productivity, but are not reflected in the proportion of total organic carbon within the sediment. During the Younger Dryas and between 6,000 and 2,800 cal. years BP, concentrations and accumulation rates of land-plant-derived C₂₉-steroids (β-sitosterol, stigmastanol and stigmasterol), in combination with a relatively low HI, indicate periods of enhanced terrigenous input to the lake. For the Younger Dryas, higher runoff can be attributed to a cold climate, leading to decreased vegetation cover and increased erosion. After 6,000 cal. years BP, high terrestrial input may be explained by enhanced precipitation. Biomarker and HI results, in combination with archaeological studies, raise the question as to whether lakeshore settlements affected sedimentation in Upper Lake Constance between 6,000 and 2,800 cal. years BP.  相似文献   

中国农业氧化亚氮排放情景研究   总被引：2，自引：0，他引：2  

李迎春  林而达  熊伟 《地理科学进展》2009,28(4)

采用国际应用系统分析研究所的"牲畜和粮食产量动态模型",模拟出2000-2030年间中国粮食和牲畜的数量和需求量的地理分布,然后应用GAINS模型预测我国未来农业N2O排放量。结果显示,2000年我国农业N2O排放量为1533ktN2O,到2030年将增加到2000ktN2O左右,增长31%;农田N2O排放占农业N2O总排放量的80%,2030年农田N2O的排放量比2000年增长37%。由于活动水平数据的模拟结果不同,各情景的N2O排放量不同,其中INMIC_低情景中N2O的排放量稍高于中、高排放情景。我国农业N2O排放主要集中在山东、河南、四川、河北,江苏、湖南、云南、安徽等省,到2030年,黑龙江、内蒙古、新疆、云南和湖南五省的N2O增加量在30ktN2O以上。硝化抑制剂作为N2O的减排措施,从2015年开始实施,减排效率由4%上升到16%。采用IPCC默认排放因子会高估我国农田N2O排放。  相似文献   

利用遥感技术建立墨西哥热带地上生物量模型(英文)     

AGUIRRE-SALADO Carlos Arturo  TREVIO-GARZA Eduardo Javier  AGUIRRE-CALDERóN Oscar Alberto  JIMéNEZ-PéREZ Javier  GONZáLEZ-TAGLE Marco Aurelio  VALDEZ-LAZALDE José René  MIRANDA-ARAGóN Liliana  AGUIRRE-SALADO Alejandro Iván 《地理学报(英文版)》2012,22(4):669-680

Spatially-explicit estimation of aboveground biomass(AGB) plays an important role to generate action policies focused in climate change mitigation,since carbon(C) retained in the biomass is vital for regulating Earth’s temperature.This work estimates AGB using both chlorophyll(red,near infrared) and moisture(middle infrared) based normalized vegetation indices constructed with MCD43A4 MODerate-resolution Imaging Spectroradiometer(MODIS) and MOD44B vegetation continuous fields(VCF) data.The study area is located in San Luis Potosí,Mexico,a region that comprises a part of the upper limit of the intertropical zone.AGB estimations were made using both individual tree data from the National Forest Inventory of Mexico and allometric equations reported in scientific literature.Linear and nonlinear(expo-nential) models were fitted to find their predictive potential when using satellite spectral data as explanatory variables.Highly-significant correlations(p = 0.01) were found between all the explaining variables tested.NDVI62,linked to chlorophyll content and moisture stress,showed the highest correlation.The best model(nonlinear) showed an index of fit(Pseudo-r2) equal to 0.77 and a root mean square error equal to 26.00 Mg/ha using NDVI62 and VCF as explanatory variables.Validation correlation coefficients were similar for both models:lin-ear(r = 0.87**) and nonlinear(r = 0.86**).  相似文献   

1999—2009年新疆能源消费碳排放的因素分解及实证研究     

顾成军  龚新蜀 《地域研究与开发》2012,31(3):140-144

从影响因素角度用LMDI分解方法对新疆1999—2009年的碳排放进行研究。结果表明:能源结构和能源强度对新疆人均碳排放增长起抑制效应,且能源强度的抑制效应大于能源结构的抑制效应;产业规模和人口规模对新疆人均碳排放增长起拉动效应,且产业规模的拉动效应大于人口规模的拉动效应。能源强度和能源结构的抑制效应难以抵消由产业规模和人口规模拉动的新疆人均碳排放的增长。在实证研究结果的基础上提出了相应的政策建议。  相似文献   

1991-2010年中国大陆化石能源消费的CO₂排放研究（英文）     

祁悦  谢高地 《资源与生态学报(英文版)》2012,(4):324-329

本文采用IPCC推荐的表观消费量法计算了中国大陆30省区1991到2010年化石能源消费产生的CO2排放,发现:(1)排放总量由 2293.01Mt 增长到 7467.77Mt;(2)煤炭消费的排放比重最高达到79.98%;(3)人均排放量由 1.98t 增长至 5.57t;(4)CO2排放强度显著降低,由6.66 kg USD-1降至1.07kg USD-1,近年来趋于稳定;(5)区域发展不平衡始终存在,根据省际数据,在一些落后地区经济增长过度依赖于化石能源消费。关于CO2高排放,中国已经做出承诺并采取了行动。基于对可持续发展和全球气候变化不确定性的综合考虑,健康的产业结构、化石能源集约利用,以及区域发展平衡应更加受到重视。  相似文献   

不同游客吸引半径景区国内旅游交通碳排放特征比较   总被引：7，自引：0，他引：7  

包战雄  袁书琪  陈光水 《地理科学》2012,(10):1168-1175

旅游交通是旅游业碳排放的最重要环节。选择具有不同游客吸引半径的福州国家森林公园、太姥山山岳景区、武夷山风景名胜区为研究对象,通过对游客交通的问卷调查,探讨不同景区国内旅游交通碳排放的基本规律。研究表明,随着游客吸引半径增加,人均碳排放量显著增加,表现为福州森林公园<太姥山<武夷山。虽然每人每公里碳排放量亦表现为福州森林公园<太姥山<武夷山,但人均旅行距离的增大则是人均碳排放量增加的最主要因素。在350 km以内,每人每公里碳排放量和人均碳排放量随距离增加变化不明显或略微下降;而350 km以上,两者均随距离增加而急剧增长,这与距离对交通方式选择的影响有关。从旅游交通碳排放特征看,350 km大致可作为中途和长途旅行划分的界线。3个景区的年碳排放总量大小顺序为:武夷山>太姥山>福州森林公园,平均碳排放密度则表现为武夷山>福州森林公园>太姥山。各景区长途旅游者和乘坐飞机旅游者均占景区旅游交通碳排放的大部分,且其比例随景区游客吸引半径的增加而增多。因而减少长途旅行和乘坐飞机次数是降低景区旅游交通碳排放量的重要途径。  相似文献   

国际碳税格局及其对中国的启示     

裴惠娟  曾静静  曲建升 《气候变化研究进展》2015,11(6):412-419

本文在总结分析全球已经实施碳税的国家碳税实施情况及其效果,评价分析国内外学者对中国征收碳税的相关研究和科学观点的基础上,针对中国碳税设计提出如下建议：目前实施碳税的大多是发达国家,国际上征收碳税的舆论日益高涨,但国内对碳税征收要素研究还不透彻,依据中国的国情开征碳税环境尚不成熟,未来需要进一步加强对碳税开征各要素的调研。  相似文献   

EU ETS试验阶段微观交易大数据分析及其对中国的启示     

刘寅鹏  郭剑锋  范英 《气候变化研究进展》2015,11(6):420-428

通过对欧盟独立交易登记系统（CITL）的抓取、识别、清洗与融合构建了全样本的交易大数据集合,完整地重现了欧盟碳排放权交易体系（EU ETS）在试验阶段的市场微观结构。进而从市场内部微观视角出发,对EU ETS的市场微观体系、排放企业的微观交易行为,以及市场供需微观演化等予以分析,结果表明在市场建立初期：排放企业的交易大多是以配额履约为目的;交易行为呈现活跃度低、季节性和同向性的特点;市场上少量的高排放企业凭借其在配额总量、资金和信息上的优势在交易中占据了主导地位。此外,微观行为数据还反映了金融部门在碳配额交易中的作用：配额在前期流向金融部门使得供过于求的状况有所缓解,但当配额流出金融部门时,市场供需失调的情况被迅速放大。在碳市场建立初期,理解EU ETS市场参与者微观行为特点以及潜在的风险,对中国即将启动的全国统一碳排放权交易体系的机制设计有重要的启示意义。  相似文献