Wetlands in China: Feature, value and protection   总被引：2，自引：1，他引：1  

Xian-guo Lu  Hong-yu Liu  Qing Yang 《中国地理科学(英文版)》2000,10(4):296-301

The estimated total area of wetland in China is more than 25.9 million hectares including about 11.9 million hectares of marshes and bogs, 9.1 million hectares of lake and about 2.2 million hectares of coastal salt marshes and mudflats. The area of wetland is equivalent to 2.7% of the land surface. China also has 2.7 million hectares of shallow sea water (less 5m in depth at low tide). Marshes and bogs are equivalent 1.3% of the land surface. Only three provinces (regions)—Qinghai, Xizang (Tibet) and Heilongjiang — have a larger total area of marsh and bog. According to the structure, type and development of wetland in different river basins, wetland can be classified nine main regions. The experiments indicate that the coefficient of the marsh to regulate flood is similar to that of lakes. Wetlands occupy 17.8% of the Sanjiang Plain area, the annual carbon contribution is 0.78 × 10⁴t. Carbon released from marsh soil return into atmosphere is 3.95 × 10⁶t/a. At present there is a sharp contradiction between population growth and natural resources shortage, causing wetland to be exerted with huge pressures and serious threats. Foundation item: Under the auspices of the Key B Item of the Chinese Academy of Sciences (KZ951-B1-201-02). Biography: LU Xian-guo (1957 —), male, a native of Changchun City, Jilin Provice, professor. His research interests include wetland process and environmental effect.  相似文献   

森林植被动态变化信息的遥感检测   总被引：10，自引：1，他引：9  

杨存建  欧晓昆  党承林  张增祥 《地球信息科学学报》2000,2(4):71-74

本文以云南省泸水县为例,探讨了利用遥感技术从LANDSAT TM图像中检测森林植被动态变化的方法。该方法,首先对1988年的LANDSAT TM图像进行几何校正,并将1999年的L ANDSAT TM图像与其配准。其次,分别从1988年和1999年的L ANDSAT TM图像中提取植被指数。然后,将1999年的植被指数减去1988年的植被指数,得到植被指数差值图像。最后,利用目视识别的方法,在植被指数差值图像上确定森林植被增加和减少的阈值,从而提取出森林植被的动态变化信息。由于云和雪的影响,造成一些伪变化的信息,为此,进一步将云和雪的信息提取出来,并将这部分伪变化信息掩模掉。该研究表明,此法可以简单有效地将森林植被的动态变化信息予以检测.  相似文献   

略论工勘施工企业信息化建设     

息韨 《南方国土资源》2000,13(3):55-56,66

市场经济是竞争经济,文章就当前广西地矿局建设工程施工企业由计划经济转向市场经济、从国内市场走向国际市场之际,如何推进企业现代化管理,以提高竞争力,提出一些见解和方案.  相似文献   

Tectonic Movement and Global Climate Change     

Yang Xuexiang  Chen Dianyou 《世界地质(英文版)》2000,3(2)

Glaciation between northern hemisphere and southern hemisphere were synchronous, the ice age occurred not in high but in low value of the eccentricity of the earth's orbit. Such facts went against the precession principle of the astronomical theory of ice age. The inhomogeneous distribution of climate consisted with the inhomogeneous distribution of ocean and continent. The north/south antisymmetry may be attributed to southward deviation of the thermal center and northward deviation of the mass center within the mantle demonstrated by seismic tomography. The core - mantle angular momentum makes rotational energy into thermal energy and mantle plumes erupt in the ocean bottom. The earth's deformation by tidal force makes the eruption of mantle plumes strong. They are the reason that glaciation between the Northern Hemisphere and Southern Hemisphere are synchronous and the ice age occurred in low value of the eccentricity of the earth' s orbit. The tectonic movement is playing a most important part in global climate change.  相似文献   

北极地区地缘关系研究综述   总被引：2，自引：0，他引：2  

叶滨鸿  程杨  王利  杨林生 《地理科学进展》2019,38(4):489-505

论文检索了科学引文索引(Web of Science)和中国知网(CNKI)中北极地区地缘关系的相关文献,借助CiteSpace文献分析软件的关键词共现分析功能,系统综述了2000年以来国内外关于北极地区地缘关系的研究重点。从研究内容上看,国外研究主要关注主权政治、航道利用、资源管理和原住民权益等主体性议题,而国内则着重关注地缘政治、航道交通、资源经济和地区治理等参与性议题。就研究方法上看,国内外研究中定性与定量方法兼具,但仍以定性方法和描述性方法为主。随着北极地区的发展,研究方法和研究视角有待丰富,研究领域和研究深度亟需进一步拓展和加强。北极地区具有重要的战略意义,未来应结合现代技术,借鉴国际上的地区发展理论,开展北极地区的可持续发展研究和中国参与研究,并构建新时代北极地区地缘环境理论。  相似文献   

Rural settlement spatial patterns and effects: Road traffic accessibility and geographic factors in Guangdong Province,China   总被引：2，自引：1，他引：1  

Yang  Ren  Xu  Qian  Xu  Xuanfang  Chen  Yanchun 《地理学报(英文版)》2019,29(2):213-230

Journal of Geographical Sciences - Based on land use classification data of remote sensing images, using kernel density, the minimal cumulative resistance model of road traffic accessibility, and a...  相似文献   

Distribution,Function and Polymorphism Characteristics of Microsatellites in Pyropia yezoensis Transcriptome     

LIU Yang  PAN Xue  XU Kuipeng  MAO Yunxiang 《中国海洋大学学报(英文版)》2019,(3):693-700

  相似文献   

Tidal Effects on the Bottom Thermal Front of North Yellow Sea Cold Water Mass near Zhangzi Island in Summer 2009     

XIA Yingying  BAO Xianwen  SONG Dehai  DING Yang  WAN Kai  YAN Yuhan 《中国海洋大学学报(英文版)》2019,(4)

Three seabed-mounted TD/CTD chains and two upward-looking acoustic Doppler current profilers(ADCPs) in the southwest of Zhangzi Island are used and a simultaneous cruise observation in the northern North Yellow Sea(NYS) is conducted to study temperature variation in the bottom thermal front zone of the NYS Cold Water Mass(NYSCWM) during the summer of 2009. In the flood-ebb tidal cycles, the bottom temperature decreases(increases) during flood(ebb) tides, which are dominated by the tidal-current induced horizontal advection. The ebb tide-induced temperature increase is larger than the flood tide-induced temperature decrease due to seasonal warming. In the spring-neap tidal cycles, the temperature and the vertical temperature structure show notable fortnightly variation from 16 July to 25 August. The bottom temperature increases from neap to spring tides and decreases from spring to neap. The Richardson number demonstrates strengthened vertical mixing during spring tides but enhanced stratification during neap tides. The spring-neap variation in vertical shear caused by tidal current is the dominant factor that induces the fortnightly variation in vertical mixing and thus bottom temperature.  相似文献   

济源地区中-下三叠统碎屑锆石年代学特征及其物源分析     

彭深远  杨文涛  王艳鹏  仲聪聪 《地质科技通报》2019,38(5):126-137

沉积物源组成及其演化是研究沉积盆地及盆山系统演化的关键。对济源地区中-下三叠统3个组进行了碎屑锆石U-Pb同位素分析,结果显示,下三叠统刘家沟组碎屑锆石具有6个年龄峰值:270,329,385,450,1885,2511Ma,其中晚古生代碎屑锆石应来自内蒙古隆起,早古生代碎屑锆石来自秦岭造山带,而新太古代-古元古代碎屑锆石则来自华北克拉通基底。下三叠统和尚沟组碎屑锆石年龄主峰值为420Ma,次峰值为745Ma和952Ma,均来自秦岭造山带。中三叠统二马营组碎屑锆石年龄主峰值为254Ma,可能来自华北板块南缘再旋回的沉积物,次峰值为1690Ma和2524Ma,应来自华北克拉通基底,其中1690Ma的碎屑锆石对应了华北板块南缘广泛出露的熊耳群。新元古界碎屑锆石由刘家沟组至和尚沟组增多,说明秦岭造山带基底逐渐剥露,是造山作用增强的体现。中三叠世末,秦岭造山带进入全面碰撞造山阶段,从地质演化过程来看,秦岭造山带在中三叠世也应处于持续隆升状态,然而二马营组中却没有来自秦岭造山带的碎屑锆石记录,而是以华北板块南缘盖层和基底为主,推测秦岭造山带的造山作用影响到了华北板块南缘,使华北板块南缘不断抬升,阻挡了秦岭造山带为济源地区提供沉积物。  相似文献   

重庆市主体功能区识别的主导因素与空间稳定性约束机理     

汪洋  王力力  祁鹏卫  刘志海 《地理学报》2019,74(1):44-62

主体功能区规划已上升为国家制度和战略,对中国长期空间发展格局优化与再组织将发挥积极的引导和约束作用。从地域性角度出发,探寻主体功能区发生性(形成与演化)和反馈性(识别与规划)时空机理与规律是地理学具有时代意义的重要科学问题。以重庆市为例,通过国土空间开发条件综合评价,识别了主体功能区划分的适宜性空间格局。基于对西南山区发展约束条件的基本认识,提出了地域主体功能空间分异的主导性约束假设,设定地形和区位为原生性主导因素,验证了其与区划指标系统的定量关联性,以此为基础解析了主导因素约束机理并提出了地域主体功能区的空间稳定性机制。研究发现:①开发与保护适宜性识别结果的格局指向清晰。城市化适宜的区域主要集中于都市区和部分周边区县,区域副中心(万州和黔江)适宜性也相对较高。生态保护适宜的区域集中于渝东北秦巴山区及部分三峡库区区县,同时包括渝东南武陵山区所在区县。②地形和区位因子在本区域对主体功能区的识别与形成具有主导约束作用。回归分析显示,主体功能区划指标与地形因子相关性水平达到显著的超过70%,区位因子超过40%;两者综合后与区划标志变量(A、B指数)的相线性相关拟合度R2均超过0.8;地理探测器发现,地形和区位因子对区划指标的约束性分别有9个和7个达到0.05显著性水平,对A、B指数的解释度分别约为70%和60%,两者叠加后,约束水平全部达到显著,对A、B指数的解释度在90%左右。③空间稳定性机制表现为两个方面,其一是基于主导因素约束的稳定性传递机制,称为客观稳定性;其二是基于指标体系的局域相对性和算法的内部抵消机制,称为主观稳定性。两种机制的协同性验证了区划技术系统的地域适应性和科学性。  相似文献