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1.
《中国地理与资源文摘》2003,(1)
1叮34 2003010066长江河口淡水端溶解态无机氮磷的通t二The nuxes of thedi翔Iv司illorganie nitrogen and phOSphoruS at freshwater exld-melnber in the chall自iang estuary膊瑞标,沈焕庭//海洋学报.一2002,24(4)一34一43 1998年2和9月在长江河口淡水端连续观测了DIN,Pq3一,流速和流向.结果表明,溶解态无机氮、磷浓度的时空变化较复杂;1998年2月Nq一,Nq一,N践+和l飞玉’-的月通量分别为168241,974.4,19335和2648t,9月的月通量分别为905678,8317,5797和6281t;1998年Nq一,Nq一,N执十和1心月’一年通量分别为497.1只10‘,3.9llK104,… 相似文献
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《中国地理与资源文摘》2003,(4)
P722.6,P731 2003042948东海初级生产力遥感反演及其时空演化机制二Estimation ofoeean prlmary Produetivlty by remote sensing and intr以Iuetio;、卞ospatio一tenlporal variation meehanism for the East China Sea‘李国胜,王芳…川地理学报一2003,58(4)一483一493 针对基于SeawiFs的海洋叶绿素浓度SeaBA入1模型反演结果,在中国东海海域分别建立了工、n类水体的修订模式,反演计算获得了我国东海海域1998年各月叶绿素浓度的分布,并根据真光层深度与海水漫射衰减系数之间的关系.利用SeawiFs的K寺,、遥感资料反演获得的1998年各月… 相似文献
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《中国地理与资源文摘》2004,(3)
P343‘5 2004031829长江河口橄沙东滩自然演变及工程影响=Na拟间创d祀-ment and efflect of project in theH即邵ha EastSI刃al of theC坛川自i斑瑶Ri吧巴灿a石ne/桑永尧,虞志英…//东海海洋一2(X)3,21(3)一14一23 横沙东滩(含横沙浅滩)是长江河口主要浅滩之一,在浅滩两侧(北港和北槽主槽)水流控制下,受浅滩横比降形成的过滩水流和较强的风浪作用影响,滩面长期以来少有淤涨.通过对1995一2002年的地形资料(吴淞基面)进行研究分析表明:从总体上着随着北港主槽向南岸进通,造成横沙东滩窜沟西部到白条子沙之间的滩区北沿明显内凹;随着长江口… 相似文献
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1998年长江洪水的特点与警示 总被引：11，自引：1，他引：10
1998年长江洪水是自1954年以来又一次全流域性特大洪水,其特点是：气候异常,受厄尔尼诺/拉尼娜影响;水位高,持续时间长;上中下游洪水遭遇;受灾经济损失大。1998年洪水给人们的警示是：历史洪水多成组出现,防洪不能松懈;平垸行洪,势在必行;分蓄洪区不能形同虚设;大规模退田还湖,并不现实可行;长江上游分洪是防洪上的奇迹;调用“土壤水库”是防洪治本之策。 相似文献
6.
《中国地理与资源文摘》2004,(2)
l叮36 .4 2004020954长江口潮滩植物对沉积物铁的地球化学循环及磁性特征的影响二In助enee of plant ong“犯h巴nical eyeli昭ofi二即d then坦卯etic pmpe叭ies of intertidal刘i~ts in the Yangt沈EStu-ary廊晓非,张卫国…//沉积学报一2003,21(3)一495一499 通过长江河口高潮滩芦苇带沉积物柱状样CYLWA一1活性铁、有机质、粒度分析及磁性测量,探讨潮滩植物对沉积物铁的地球化学循环及磁性特征变化的影响.结果显示,沉积物柱状样总体上以Fez十占优势,且含量随深度逐渐增加.图2参25(许桂红)N1’V 131.3,种31.3 2004020955长江口三维潮流… 相似文献
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《中国地理与资源文摘》2005,(1)
X13,X14 4 2 0 0 5 0 10 0 6 6长江口潮滩有机质来源的C、N稳定同位素示踪 =CarbonandnitrogenstableisotopesastracerstosourceorganicmatterintheYangtzeEstuary/刘敏 ,侯立军…∥地理学报 .—2 0 0 4 ,5 9(6 ) .— 918～ 92 6依据长江河口潮滩自然环境特征和受人文活动影响的差异性 ,沿长江河口南岸潮滩选取了 12个典型的监测站位 ,并分别于洪水季节 (7月份 )和枯水季节 (2月份 )在各监测站位进行了表层 (0 - 2cm)沉积物样品的采集 .对表层沉积物有机质中稳定碳、氮同位素进行分析与测试发现 ,7月份稳定碳同位素值普遍低于 2月份的稳… 相似文献
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新课引入
展示1931年、1954年和1998年长江流域三次特大洪水的材料,要求学生回忆并讨论长江上、中、下游的水文特征,以及水灾的防治。经过学生讨论,教师总结,指明长江在给我们带来灾害的同时,更多的是给我们带来了流域内外经济发展的机遇,以此导入新课。 相似文献
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《中国地理与资源文摘》2004,(1)
1叮36 2004010061黄河口拦门沙研究动态二The research trendsof~th二nd-bar in27(6)YellowRiver/黄海挺,杨作升…//海洋科学.一2003一35一37 近年来,随着黄河三角洲地区经济的不断发展,特别是胜利油田的发展,越来越要求黄河口有稳定的流路.由于黄河口拦门沙特殊的地理位置及其特殊水动力环境,使得黄河口拦门在河口动力学、河口沉积地球化学研究中都有着不可代替的作用.图1参l7(许桂红)N1叮36 2004010062长江河口悬浮物对几种金属吸附的pH效应“Effects of pHon od,〕11〕tion of several meta[S to su印ended sediment in theChan颤ang… 相似文献
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The agricultural and land policies in China are always focused on protecting its food supply and security because of the country’s large population and improved diets.The crop production guide ’Take Grain as the Key Link’ prompted peasants to plant grain on most of the agricultural land,leading to the majority of fertilizer being used in grain crops for many years in China.This situation has changed dramatically in recent years.Based on data pertaining to provincial crops sown area and fertilizer use per unit area in 1998 and 2008,the temporal and spatial variations of China’s fertilizer consumption by crops were analyzed at the provincial level,and the results are presented here.(1) Fertilizer consumption in China grew strongly in the last decade,while the growth was mainly attributable to the increase of fertilizer con-sumption by horticultural crops.The fertilizer consumption of grain crops dropped from 71.0% in 1998 to 57.8% in 2008.Thus,it is concluded that the emphasis of fertilizer consumption is shifting toward horticultural crops.(2) There were marked differences in the growth rates of fertilizer consumption from the regional point of view.The national average growth rate of fertilizer consumption was 31.9% during 1998-2008.The western and northeastern parts of the country came close to the national average,while the eastern part was lower,with an average of 13.0%,and central China was much higher(50.8%).The increase of fertilizer consumption in central and west China was higher than the other zones,which already ac-counted for 77.9% of the national total.Thus,it is concluded that the consumption emphasis of chemical fertilizer shifts toward the central and western regions.(3) The decline of fertilizer consumption by grain crops was largely due to the decrease in sown area compared with the increase by vegetable crops attributable to the enlarging sown area;the increase by orchard crops was affected by both expanding the sown area and fertilizer use per unit area. 相似文献
12.
China＇s economic development stage and its spatiotemporal evolution： A prefectural-level analysis 总被引：2，自引：0，他引：2
As important mechanisms of regional strategy and policy,prefecture-level regions have played an increasingly significant role in the development of China’s economy.However,little research has grasped the essence of the economic development stage and the spatio-temporal evolution process at the prefecture level;this may lead to biased policies and their ineffective implementations.Based on Chenery’s economic development theory,this paper identifies China’s economic development stages at both national and prefectural levels.Both the Global Moran I index and the Getis-Ord Gi* index are employed to investigate the spatio-temporal evolution of China’s economic development from 1990 to 2010.Major conclusions can be drawn as follows.(1) China’s economic development is generally in the state of agglomeration.It entered the Primary Production Stage in 1990,and the Middle Industrialized Stage in 2010,with a ’balanced-unbalanced-gradually rebalanced’ pattern in the process.(2) China’s rapid economic growth experienced a spatial shift from the coastal areas to the the inland areas.Most advanced cities in mid-western China can be roughly categorized into regional hub cities and resource-dependent cities.(3) Hot spots in China’s economy moved northward and westward.The interactions between cities and prefectures became weaker in Eastern China,while cities and prefectures in Central and Western China were still at the stage of individual development,with limited effect on the surrounding cities.(4) While the overall growth rate of China’s economy has gradually slowed down during the past two decades,the growth rate of cities and prefectures in Central and Western China was much faster than those in coastal areas.(5) Areas rich in resources,such as Xinjiang and Inner Mongolia,have become the new hot spots of economic growth in recent years.For these regions,however,more attention needs to be paid to their unbalanced industrial structures and the lagging social development against the backdrop of the rapid economic growth,driven predominantly by the exploitation of resources. 相似文献
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《中国地理与资源文摘》2007,(1)
P237.92007010165黄、东海海面地形在1993-2001年间的变化探讨=The research on sea surface topography in Yellow Sea and East China Sea in1993-2001/钟鹤翔,谢志仁…∥测绘学报.—2006,35(1).—9~14利用Topex/Poseidon卫星的SSHA数据对黄、东海1993-2001年期间的平均海面地形的空间形态特征、变化速率的空间分布特征及年内变化特征等3个方面进行分析.研究结果表明,该海区9年平均海面地形的基本特征为:东南高、西北低,由东南向西北倾斜,最大高差超过90cm;1993-2001年期间全海区均呈现海面上升趋势,上升速率值在5~8.6mm/a之间,海面… 相似文献
14.
长江三峡及江汉平原地区全新世环境考古与异常洪涝灾害研究 总被引：76，自引：6，他引：76
根据对长江三峡及江汉平原地区新石器文化遗址的分布、文化间断、埋藏古树和历史资料探讨了本区全新世异常洪水频率的变化，共划分出４个洪水频率发期：第Ⅰ洪水期（８０００ａＢＰ－５５００ａＢＰ）共发生特大洪水９次；第Ⅱ洪水期（４７００ａＢＰ－３５００ａＢＰ），至少发生特大洪水９次；第Ⅲ洪水期（２２００ａＢＰ－７００ａＰＢ），共发生特大洪水５２次，其中在小冰期最冷期（３００ａＢＰ－１００ａＢＰ）就有４０次。前 相似文献
15.
东海初级生产力遥感反演及其时空演化机制 总被引：23，自引：1，他引：22
针对基于SeaWiFS的海洋叶绿素浓度SeaBAM模型反演结果,在中国东海海域分别建立了Ⅰ、Ⅱ类水体的修订模式,反演计算获得了我国东海海域1998年各月叶绿素浓度的分布,并根据真光层深度与海水漫射衰减系数之间的关系,利用SeaWiFS的K490遥感资料反演获得的1998年各月真光层深度的分布,在VGPM模型支持下,反演计算获得了中国东海海域1998年的逐月初级生产力时空分布以及全年累积初级生产力分布状况。对东海海域海洋初级生产力逐月时空变化特征及其影响机制的初步研究结果表明,整个东海海域初级生产力的逐月变化具有明显的双峰特征,表现为冬季最低,春季迅速上升达到最高,夏季略有下降,秋季又略有回升。海域初级生产力日平均值为560.03 mg/m2/d,远高于世界亚热带海域平均状况。年平均值为236.95 g/m2/a。控制东海海洋初级生产力时空变化的主要因素可能包括叶绿素浓度分布、温度条件、长江冲淡水变化,以及真光层深度、海流锋面过程等,不同海区初级生产力时空变化的主要控制因素有所不同。 相似文献
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根据我国首次北极科学考察所获 CTD资料 ,分析了白令海和楚科奇海的水文特征和水团结构。研究表明 :(1 )该两海域温、盐度的分布有着明显的区域性差异。楚科奇海的温、盐度普遍低于白令海。 (2 )夏季 ,白令海大部分水域温度垂直分布的突出特点是 :在 2 0 m和 2 5 0 m间存在温度低于 3°C的中层冷水。 (3 )在楚科奇海北纬 70°以北海域 ,不论是水温或盐度皆明显减小 ,从而在此区域形成强的温、盐度锋带。 (4)在白令海存在三种水团 ,而楚科奇海的水团则大致分为两类 相似文献
17.
《中国地理与资源文摘》2003,(4)
利用长江口泥质区及其邻近海域夏季和冬季的悬浮体、温度和盐度资料,就长江口泥质区悬浮体的季节性分布和沉积效应进行探讨.由于台湾暖流的强烈阻隔作用,夏季和冬季长江入海的泥沙基本滞留在123°15’E以西的内陆架进行搬运和沉积。长江入海沉积物供应量、台湾暖流、浙 相似文献
18.
《地理学报(英文版)》2017,(7)
Though many studies have focused on the causes of shifts in trend of temperature, whether the response of vegetation growth to temperature has changed is still not very clear. In this study, we analyzed the spatial features of the trend changes of temperature during the growing season and the response of vegetation growth in China based on observed climatic data and the normalized difference vegetation index(NDVI) from 1984 to 2011. An obvious warming to cooling shift during growing season from the period 1984–1997 to the period 1998–2011 was identified in the northern and northeastern regions of China, whereas a totally converse shift was observed in the southern and western regions, suggesting large spatial heterogeneity of changes of the trend of growing season temperature throughout China. China as a whole, a significant positive relationship between vegetation growth and temperature during 1984 to 1997 has been greatly weakened during 1998–2011. This change of response of vegetation growth to temperature has also been confirmed by Granger causality test. On regional scales, obvious shifts in relationship between vegetation growth and temperature were identified in temperate desert region and rainforest region. Furthermore, by comprehensively analyzing of the relationship between NDVI and climate variables, an overall reduction of impacts of climate factors on vegetation growth was identified over China during recent years, indicating enhanced influences from human associated activities. 相似文献
19.
1788年夏季,长江流域持久性洪水暴雨范围广,特大洪水暴雨时空分布趋势呈现绳套形.这种持久性洪水暴雨前期冬春两季,前冬系流域性范围降雪,嗣后,流域主要为持时长和范围广的多雨水气候异常现象,中下游流域入梅期早. 相似文献
20.
长江南京段历史洪水位追溯 总被引：14，自引：0，他引：14
沿长江南岸幕府山、燕子矶岸段的石灰岩崖壁上,保留着数道受江水浸淹形成的色深且具有溶蚀孔隙的水平印痕,沿江一线分布。在采石矶岸段的岩壁上也存在着高程大致相当的水位痕迹,反映出是保存在长江南岸岩壁上的区域性洪水位遗迹。经查阅现代水文记录与历史文献,分析对比区域地貌与沉积地层,初步论定：高出长江江面5~6 m,高程分别为8.5 m和9.5 m的第一道和第二道水位遗迹是与现代长江洪水位相当的古洪水位遗迹,目前虽然已脱离长江江面,但现代长江洪水仍可达到此高度,其重现期为10~50年;高程为10.5 m的第三道水位遗迹较南京有文字记载的百年一遇特大洪水位仍高出0.3 m,相当于南京地区100~200年一遇的大洪水水位,由此印证长江南京段防洪堤高度合适;而最高的一道古水位遗迹高程为12.8 m,可能相当于全新世高海面时的洪水位。 相似文献