The relationship between cyanobacteria and environmental factors in the Bering Sea     

肖天  孙松  张武昌  李超伦  金明明 《极地研究(英文版)》2002,13(2)

During the first Chinese Scientific Expedition to the Arctic in July - September 1999, cyanobacteria in the Bering Sea were measured by epifluorescence microscopy. Cyanobacterial abundance varied from 0 to 7. 93 × 103 cell/ml and decreased along a northerly directed latitudinal gradient in horizontal distribution. Cyanobacteria did not occur at station Bl - 12 (north of 60 °N). Vertically, high cya-nobacterial abundance appeared in the upper 25 - 50 m and decreased rapidly below 50 m. There were no cyanobacteria at the 150 m. Seawater temperature and NH4+ -N are suggested to affect the distribution of cyanobacteria.  相似文献   

Regional Summer Temperature Decrease against Global Warming in China, Landform Effect？   总被引：1，自引：1，他引：0  

LU Aigang PANG Deqian HE Yuanqing PANG Hongxi WANG Tianming GE Jianping 《山地科学学报》2007,4(1):86-90

The data of 160 national meteorological observatory(NMO)stations with long-term monthly temperature data for China were analyzed in this study to show the basin-centered summer temperature decrease against global warming in the past half century. The summer and winter isotherm structures of 1950s and 1990s worked out by interpolation show the isotherm structure variations: the isotherm structure generally moves northward in winter, but in summer it is characterized with separate high-temperature and low-temperature centers and the isotherm structure moves inward the centers with global warming, indicating that the temperature in the highland areas increases but that in the lowland areas decreases in the summer of the duration. The possible mechanism of the basin-centered temperature decrease in summer is discussed in this paper.  相似文献   

Determination of ice thickness, subice topography and ice vol-ume at Glacier No. 1 in Tien Shan, China by ground penetrating radar   总被引：1，自引：0，他引：1  

孙波  张鹏  焦克勤  邓新生  温家洪 《极地研究(英文版)》2003,14(2)

We describe a radio-echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No. 1 , in Tien Shan, China, using ground-penetrating radar (GPR). Radar data were collected with 100-MHz antennas that were spaced at 4 m with a step size of 8 m. The images produced from radar survey clearly show the continuity of bedrock echoes and the undulation features of the bedrock surface. Radar results show that the maximum ice thickness of Glacier No. 1 is 133 m, the thickness of the east branch of Glacier No. 1 averages at 58. 77 m while that of the west branch of Glacier No. 1 averages at 44. 84 m. Calculation on ice volume indicates that the ice volume of the east branch of Glacier No. 1 is 51. 87 × 106 m3 and that of the west branch of Glacier No. 1 is 20. 21 × 106 m3. The amplitude of the undulation of the bedrock surface topography revealed by radar profiles is larger than that of the glacier surface topography, indicating that the surface relief does  相似文献   

Characteristics of DDF at Baishui Glacier No.1 Region in Yulong Snow Mountain     

和献中  杜建括  吉亚鹏  张宁宁  李宗省  王世金  Wilfred H Theakstone 《中国地质大学学报(英文版)》2010,(2)

Based on observed mass balance and meteorological data since September 2008 and ablation data by the expedition team of Tibetan plateau from June to August 1982 at Baishui(白水) Glacier No.1 region,we analyzed the spatial and temporal changes of degree-day factor(DDF) of the Baishui Glacier No.1 following the changes of space,time,and temperature,which lays a theoretical foundation to establish DDF model.The results indicate that the melting DDF of ice showed a significant down-ward trend with rising temperat...  相似文献   

Chemical Composition of Aerosol and Fresh Snow and Tourism Influences at Baishui Glacier No.1 from Mt. Yulong,Southeastern Tibetan Plateau     

张宁宁  何元庆  Wilfred H Theakstone  庞洪喜 《中国地质大学学报(英文版)》2010,(2)

Aerosol and snow samples were collected at ablation zone of Baishui(白水) Glacier No.1,Mt.Yulong(玉龙),from May to June,2006.The concentrations of Cl-,NO3-,SO42-,Na+,K+,Mg2+,and Ca2+ were determined by ion chromatograph both in aerosol and snow samples.The average totalaerosol loading is 25.45 neq·scm-1,NO3-and Na+ are the dominant soluble ions in the aerosol,accounting for 39% and 21% of average total aerosol loading,respectively.Monsoon circulation reduces the concentration of most ions,indicating that wet sc...  相似文献   

Paleofire Indicated by Polycyclic Aromatic Hydrocarbons in Soil of Jinluojia Archaeological Site,Hubei,China     

邹胜利  李仁成  谢树成  朱俊英  王新君  黄俊华 《中国地质大学学报(英文版)》2010,(3)

Combustion-derived and land-plant-derived polycyclic aromatic hydrocarbons (PAHs) have been investigated by using the GC-MS analysis in an ancient soil profile from Jinluojia (金罗家) archaeological site at Macheng (麻城),Hubei (湖北) Province,Central China.Retene,cadalene and simonellite were proposed to be derived from contemporary land plants.The pyrolytic PAHs identified include fluoranthene,pyrene,benzofluoranthenes,benzo[e]pyrene and benzo[a]pyrene.The distribution of these pyrolytic PAHs varies with depth,d...  相似文献   

NUMERICA STUDY OF THUNDERSTORM ELECTRIFICATION WITH A THREE-DIMENSIONAL DYNAMICS AND ELECTRIFICATION COUPLED MODEL—MODEL DESCRIPTION AND PARAMETERIZATION OF ELECTRICAL PROCESSES          下载免费PDF全文

孙安平  言穆弘  张义军  张鸿发  黄美元 《Acta Meteorologica Sinica》2002,(1)

A new three-dimensional dynamics and electrification coupled model has been developed forinvestigating the characteristics of microphysics,dynamics and electrification insidethunderstorms.This model is basically modified from a three-dimensional,time-dependent,anddual-parameter cloud model originally established in IAP(Institute of Atmospheric Physics)and atwo-dimensional axisymmetric cloud dynamics and electrification coupled model.Primarymodifications to the model include not only the coupling of electrification with dynamical andmicrophysical processes,but also the lightning discharge process and screening layer effect at thecloud top as well.Apart from including a full treatment of small ions with attachment to sixclasses of hydrometeors,the inductive and non-inductive charging mechanisms are more specificallyconsidered.A case simulation of July 19.1981 CCOPE is performed aiming to validate thepotential capability of the model.Comparison between model results and observations reveals thatthe model has the capacity to reproduce many of the observed characteristics of thunderstorms indynamical,microphysical,and electrical aspects.  相似文献   

西藏中尼公路沿线的泥石流   总被引：10，自引：0，他引：10  

何易平  马东涛  崔鹏  陈瑞 《地理学报》2002,57(3):275-283

中尼公路是西藏西南部经济发展的动脉，沿线泥石流灾害严重威胁到线路的正常运营，本研究根据航空照片和卫星图象解译结果，结合现场踏勘校对，深入地研究了沿线700km范围内的环境背景条件和泥石流活动规律，确定沿线有泥石流沟842条，其中沟谷型泥石流沟474条，在公路一侧直接危害公路的沟谷型泥石流241条，深入地探讨了这一高原特殊环境下的泥石流活动特性；为公路部门提供了泥石流防治方案，成为线路整治改建的依据。  相似文献   

RIVER BED DYNAMICS AND BED SEDIMENT TRANSPORTIN MOUNTAIN TORRENTS IN MOUNTAIN TORRENTS     

Peter Ergenzinger Carmen de Jong Berlin Environmental Research Group Institut fur Geographische Wissenschaften Freie Universitut Berlin Grunewaldstr.  Berlin  Germany 《国际泥沙研究》1997,(3)

LIN~DUCTIONTheinvenigationsofrivermorphologyandOfriverbeddebilityresultalwaysinidalsabouttheinterrelationshipbetweenthehydrauliccondihons,sc(hant~rtandbeddynndcs.ThedeCOuragingfactforsuchinveedgationsarethecomplexityoftheseSystemsandthehugenumberofimportantvariables.IfwefollowSimonsetal(1965)andall~eneeandtheconcentrationsofSUSPendedlOadandbedloadthefollowingparametersarethepnncapleVarialllesf-av~velocityofnow,diStributionofnowvelociticsacdeadofturbulence-meandepthacthedistributionofde…  相似文献   

荒漠绿洲PRED系统特征与可持续发展定量研究   总被引：8，自引：4，他引：8  

苏培玺  张小军  刘新民 《地理科学》2001,6(6):519-524

荒漠绿洲PRED系统是一个相当脆弱的系统，自然灾害频繁、水分失衡导致的生态风险大。在分析其特征的基础上，建立了衡量可持续发展的指标体系并运用层次分析法得出了这些因子对绿洲PRED系统可持续发展的权值，影响最大的前三位因子是：人均水资源量、绿洲化面积、人口素质、其权值分别为0.124、0.077、0.062。计算了河西走廊20个县（市、区）的SDI，排在最前面的依次是：萧北蒙古族自治县、嘉峪关市和玉门市、金川区，其SDI分别为0.437、0.406、0.405，排在最后面的依次是：古浪县、民勤县、天祝藏族自治县，其SDI分别为0.150、0.213、0.217。分析了这种格局产生的原因并提出了相应对策。  相似文献