THE DISCOVERED DEEP BURIED LAKE ICE IN SOURCE REGION OF THE HUANGHE RIVER     

王绍令  李位乾 《中国地理科学(英文版)》1993,3(3):247-254

The 4.45 m-thick pure ice lens have been discovered firstly at depth from 19.81 -24.26 m in the bore No.6, which locates in north bank of the Ngoring Lake. In source region of the Huanghe (Yellow) River, 14C dating, X -ray diffraction, pollen analysis, micropalaeontology, chemical components, environmental isotope 2H, 3H, 18O and freezing point of the ice and water samples from the bore have been tested and microorganism in the ice have been also appraised with microscope. Combined with the research on geomorphy and Quaternary around the lake, the ice lens are determined as a kind of deep-buried lake ice, formed in 35,030-45,209 yr.B.P., and annual mean air temperature was about -10℃ during that time.  相似文献   

长江上游防护林体系建设要点     

钟祥浩  程根伟  杨定国  陶和平 《山地学报》1991,(2)

本区防护林体系的建设目标是:改善生态环境,发展山区经济。人口稠密区防护林体系建设成败的关健在于:能否掌握生态生产双重功能,是否具有生态社会经济三大效益。为此进行了防护林体系分类,提出了林种的生态功能指标和生产功能指标。防护林体系的生态经济分区要研究生态经济系绽的地域差异,有助于发挥各个林种的生态生产双重功能,是建设防护林体系的重要途径,为合理布局提供科学依据。  相似文献   

AREAL DIFFERENTIATION AND CONSTRUCTION OF OASIS AGRICULTURAL ECOSYSTEM IN THE SHIYANG RIVER BASIN     

张维祥  梁智睿 《中国地理科学(英文版)》1993,3(4):357-364

On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.  相似文献   

长江三峡阶地的成因机制   总被引：15，自引：0，他引：15  

杨达源 《地理学报》1988,(2)

根据对长江三峡阶地堆积物进行的野外调查与室内分析发现三峡阶地的成因具有以下特点:构成阶地上部的河漫滩相堆积、中部的冲积砾石层与作为阶地基座的基岩平台是在不同时期形成的;阶地上部河漫滩相堆积是在中全新世气候温暖、长江三峡高水位条件下形成的.因此,长江三峡阶地是在构造上升的基础上由于气候及长江三峡流量及水位变化而形成的,并非一定是间歇性构造上升的标志.  相似文献   

Reduced rates of primary production in the Columbia River Estuary following the eruption of Mt Saint Helens on 18 May 1980     

Bruce E. Frey  J.Rubén Lara-Lara  Lawrence F. Small 《Estuarine, Coastal and Shelf Science》1983,17(2):213-218

The eruption of Mt Saint Helens on 18 May 1980 resulted in a massive increase in suspended particulate material in the Columbia River Estuary, producing a substantial increase in light attenuation. Since photosynthesis in the estuarine water column is partly controlled by the depth of light penetration in the water, photosynthesis was reduced by about 75% during the period of increased turbidity. It took about five weeks for the estuary to clear. Although primary production within the estuarine water column was greatly diminished during this period, the flux of particulate carbon through the estuary was high, and the total production we estimate to have been lost amounted to only about 2% of the total particulate carbon flux just after the eruption. That the high levels of turbidity in the estuary did not induce a severe fall in the phytoplankton population is evidence that phytoplankton biomass concentrations in the Columbia River Estuary are mostly a function of import from the Columbia River, rather than a function of in situ production.  相似文献   

红水河—黔江—浔江流域气候分析     

黄洪峰  杨勤 《地理研究》1989,(4)

本文采用流域内气象站资料,以正交函数展开方法,分析了流域气候背景场的基本结构及共季节变化特征,并根据1985—1988年间在流域内若干河段的小气候考察资料,探讨河流对局地小气候要素的影响。本文给出的河陆风环流平衡气球探测结果,表明了河陆风环流结构的某些特征。  相似文献   

东江鲤鱼的生物学   总被引：1，自引：0，他引：1  

叶富良  罗平  叶星 《广东海洋大学学报》1992,(2)

东江鲤鱼年轮形成时期主要在2～8月,生长特点可用von Bertalanffy生长方程L_t=851[1-e~(-0.133(t+0.0394))]、W_t=19171.5[1-e~(-0.173(t+0.0394))]~3来表达;怀卵量3.1～63.563.5万粒,怀卵量与体长、体重的关系分别为F=5.14×10~(-2)L~2.6176、F=17905.43+138.86W;食物组成周年变化不明显。结合生物学资料,讨论了东江鲤鱼资源合理利用问题,提出最小捕捞年龄应在2龄以上,捕捞强度F=0.35左右。  相似文献   

THE RESEARCH ON THE DISTRIBUTION AND FORMS OF HEAVY METALS IN THE XIANGJIANG RIVER SEDIMENTS   总被引：1，自引：0，他引：1  

董文江  张立成  章申 《中国地理科学(英文版)》1992,2(1):42-55

In this paper, the contents and various forms of Cd, Cu, Zn and Pb in the sediments of the Xiangjiang River have been investigated. The presentation of this paper focuses on the various forms and characteristics of the heavy metals in the column sediments at Xiawan Port of Zhuzhou, which has been severely polluted by a metallurgical plant.The forms of the heavy metals discussed in this paper are: The concentration of the exchangeable forms of Cd, Cu, Zn and Pb, in the forms of carbonates and Fe/ Mn oxide in water, the combination of Cu with organic matter and form, and the proportion of the residue form at each section have been studied.  相似文献   

PROBLEMS　OF　THE　AQUATIC　ENVIRONMENT　AND　COUNTERMEASURES　IN　RAPID　ECONOMIC　DEVELOPMENT　IN　THE　ZHUJIANG　RIVER　DELTA     

温琰茂  程国佩 《中国地理科学(英文版)》1995,(1)

ＰＲＯＢＬＥＭＳＯＦＴＨＥＡＱＵＡＴＩＣＥＮＶＩＲＯＮＭＥＮＴＡＮＤＣＯＵＮＴＥＲＭＥＡＳＵＲＥＳＩＮＲＡＰＩＤＥＣＯＮＯＭＩＣＤＥＶＥＬＯＰＭＥＮＴＩＮＴＨＥＺＨＵＪＩＡＮＧＲＩＶＥＲＤＥＬＴＡ￥ＷｅｎＹａｎｍａｏ（温琰茂）；ＣｈｅｎｇＧｕｏｐｅｉ...  相似文献   

A comparison of TRMM to other basin-scale estimates of rainfall during the 1999 Hurricane Floyd flood   总被引：5，自引：2，他引：3  

Scott Curtis  Thomas W. Crawford  Scott A. Lecce 《Natural Hazards》2007,43(2):187-198

The volumetric rainfall attributed to Hurricane Floyd in 1999 was computed for the bulk of the Tar, Neuse, and Cape Fear River Basins in eastern North Carolina, USA from the Tropical Rainfall Measuring Mission (TRMM) Multi-Satellite Precipitation Analysis (TMPA) research product, and compared with volumes computed using kriged gauge data and one centrally located radar. TMPA showed similar features in the band of heaviest rainfall with kriged and radar data, but was higher in the basin-scale integrations. Furthermore, Floyd’s direct runoff volumes were computed and divided by the volumetric rainfall estimates to give runoff coefficients for the three basins. The TMPA, having the larger storm totals, would suggest greater infiltration during Floyd than the gauge and radar estimates would. Finally, we discuss a concept for adjusting the United States Department of Agriculture Natural Resources Conservation Service rainfall-runoff model when predicting discharge values from real-time TMPA in ungauged river basins.

Scott CurtisEmail:

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