能量与水分循环——气候研究的热点   总被引：6，自引：0，他引：6  

张雁 《气象》2001,27(9):9-12

主要介绍了能量与水分循环研究的关键科学问题，并介绍了近年来国际和国内开展的一系列大型科学试验计划。这些计划都是以开展大尺度水循环过程、陆面水循环过程、云与降水过程的观测试验为生长点，以分析、了解、模拟大气－陆地－海表的水分和热量交换及循环为研究基础，旨在进一步弄清气候变暖的物理成因和未来气候变化趋势；弄清中国、日本等东亚国家的旱涝形成机理；建立相应的气候模式，提出新的预报方法，从而实现较准确地预测气候变化和大尺度灾害性天气，合理调配水资源之目的。  相似文献   

1998年HUAMEX试验区的降水分析     

仪清菊  魏凤英  王明志 《气象》2001,27(9):31-34

利用1998年5－6月华南暴雨外场试验期间加密观测的降水资料，分析了试验区的降水特征，结果表明：广州试验区降水强于福建区；1小时雨量的变化，在时间上，呈现出强的脉冲特性，最大1小时雨量往往发生在依傍晚；在空间上，表现出明显的局地性；由GPS观测资料反演得到的在气可降水量（PWV）能较好地揭示暴雨发生的时段。  相似文献   

风应力的旋转和辐散分量在ENSO循环中作用的数值试验研究     

管兆勇  刘宣飞 《南京气象学院学报》2001,(4)

将 1 960～ 1 991年的月平均 FSU风应力资料分解为旋转部分和辐散辐合部分 ,分别用以强迫模式海洋。所用的模式为一个 2层热带太平洋区域海洋模式。结果表明 ,就季节变化而言 ,不论是用旋转分量还是散合分量强迫海洋 ,都不能产生合理的冷舌 ,哪怕将旋转或散合分量放大一倍或缩小二分之一 ,也不能使冷舌的强度和分布得到合理的改善。若采用气候平均的含有季节变化的风应力 (未对旋转和辐散分量进行分离 ) ,则可产生与实际相符的海表温度分布。在此基础上 ,分别叠加旋转和辐散分量的年际异常部分 ,通过对海洋的强迫 ,可产生海表温度异常。在年际异常旋转分量的强迫下 ,可产生较强的 SSTA振荡且具有明显的 ENSO周期 ;而在辐散辐合年际异常风应力的强迫下 ,则产生较弱的 SSTA,且振荡频率较高 ,ENSO周期不很明显。这些结果说明 ,风应力的涡旋和辐散辐合分量在海温季节变化和年际变化的形成中具有不同的作用 ,即合理的冷舌分布需要风应力旋转分量和散合分量同时作用于海洋方可产生 ,而仅有异常风应力的旋转强迫就可产生合理的 EL Nino/ La Nina现象。同时 ,风应力的辐散辐合分量在海洋平均状态的形成过程中是重要的 ,但在 EN-SO过程中就对海洋的作用而言则不如旋转分量重要。  相似文献   

三峡工程建成后枯水期运行的气候风险研究   总被引：2，自引：0，他引：2       下载免费PDF全文

张建敏  吴金栋等 《应用气象学报》2001,12(2):218-225

通过蒙特卡罗试验, 探讨了三峡工程建成后枯水期运行风险的评估方法。以GCM模拟试验结果为未来气候情景, 随机模拟了三峡地区在该气候情景下枯水期月降水量分布; 建立了三峡地区月径流-降水模型和三峡水库调度模型; 初步分析了长江三峡工程建成后在当前气候背景和可能未来气候情景下的运行风险。结果表明, 三峡水库的运行对气候变化反应敏感, 春季和冬季的发电风险有明显改变。  相似文献   

河南省飞机人工增雨试验方案设计   总被引：3，自引：0，他引：3  

李念童  李铁林  郑宏伟 《应用气象学报》2001,12(Z1):200-205

借鉴国内外已有的探测和分析研究成果，结合国内人工增雨飞机的性能，着重介绍在催化作业和探测时，开展等半径盘旋上升（或下降）垂直观测，和在特定高度上进行水平观测的方案设计及其资料收集、处理、存档的流程。为开展人工增雨作业、观测提供科学依据。  相似文献   

Material component to non-linear relation between sediment yield and drainage network development: an flume experimental study     

JIN De-sheng  CHEN Hao  GUO Qing-wu 《地理学报》2001,11(3):271-281

This paper examines the experimental study on influence of material component to nonlinear relation between sediment yield and drainage network development completed in the Lab. The area of flume drainage system is 81.2 m2, the longitudinal gradient and cross section slope are from 0.0348 to 0.0775 and from 0.0115 to 0.038, respectively. Different model materials with a medium diameter of 0.021 mm, 0.076 mm and 0.066 mm cover three experiments each. An artificial rainfall equipment is a sprinkler-system composed of 7 downward nozzles, distributed by hexagon type and a given rainfall intensity is 35.56 mm/hr.cm2. Three experiments are designed by process-response principle at the beginning the Ψ shaped small network is dug in the flume. Running time spans are 720 m, 1440 minutes and 540 minutes for Runs I, IV and VI, respectively. Three experiments show that the sediment yield processes are characterized by delaying with a vibration. During network development the energy of a drainage system is dissipated by two ways, of which one is increasing the number of channels (rill and gully), and the other one is enlarging the channel length. The fractal dimension of a drainage network is exactly an index of energy dissipation of a drainage morphological system. Change of this index with time is an unsymmetrical concave curve. Comparison of three experiments explains that the vibration and the delaying ratio of sediment yield processes increase with material coarsening, while the number of channel decreases. The length of channel enlarges with material fining. There exists non-linear relationship between fractal dimension and sediment yield with an unsymmetrical hyperbolic curve. The absolute value of delaying ratio of the curve  相似文献   

煤岩及煤岩加不同介质的热模拟地球化学实验--气态和液态产物的产率以及演化特征   总被引：10，自引：2，他引：10  

刘全有  刘文汇  秦胜飞  孟仟祥  王万春 《沉积学报》2001,19(3):465-468

对塔里木盆地侏罗系煤岩以及煤岩加不同介质等 4个系列以 50℃为一温阶,从 250～550℃进行热模拟实验,并对其气体产物、液态有机质进行了系统分析。结果表明:煤岩成烃过程是一个综合作用的过程,它的生气、生油与外界环境如水,粘土矿物等的辅助作用有关。随着热模拟温度的升高,各产气率呈增长趋势。介质的加入可降低有机质成烃温度,有利于液态物的产出。  相似文献   

猫岭-王家崴子金矿采矿废料的酸化潜力研究     

孙丽娜  金成洙 《矿物岩石地球化学通报》2001,20(3):203-207

为控制金矿开采废岩和选冶废料的酸化 ,利用净产酸量、净产酸势实验和柱淋溶实验 ,研究了猫岭 王家崴子金矿区采矿废石和尾矿的酸化情况。结果表明 ,在废石和尾矿的堆放过程中会发生酸化 ,且废石的产酸量远高于尾矿的产酸量 ,氰化尾矿的产酸量高于浮选尾矿的产酸量。但是 ,12 0天的淋溶实验表明 ,各种采选废物在短期内酸化现象不明显 ,与本区采矿废石和尾矿低的含硫量和系统中的缓冲能力及其外部环境因素有关 ,也反映了废物漫长的酸化过程。本研究结果为金矿开发废碴的环境管理和酸化控制提供了科学依据。  相似文献   

Oxidation Experiment of Natural Megacrystal Clinopyroxene: Implications for Assignment of Mössbauer Spectra     

ZHI Xiachen  CHEN Peng  LIN Chengzhong  CHEN Shuqing  ZHANG Guilan  LI Yuzhi  LIN Lei 《《地质学报》英文版》2001,75(1):51-58

The Mössbauer spectra of natural megacrystal clinopyroxene are usually fitted by 4 sets of symmetric doublets, A‐A', B‐B', C‐C' and D‐D', respectively, in terms of increasing Qs value in literature. But the assignments of those doublets are quite different, except the D‐D' doublet assigned to Fe³⁺at the lattice site M***1 in previous papers. Particularly, the assignment and interpretation of the C‐C' doublet are diverse. The oxidation experiments of natural megacrystal clinopyroxene collected from the Hannuoba basalt, North China, were performed under controlled conditions of temperature at 1000°C and oxygen fugacity of FMQ buffer in 1, 2, ***3 and 5 days respectively. The oxidized samples were then measured by X‐ray diffraction spectrometry and Mössbauer spectrometry. The oxidation of clinopyroxene is characterized by Fe²⁺ → Fe³⁺at M1 under the subsolidus conditions, which is consistent with the increase of the area of the D‐D' doublet when the heating time increases. Accordingly, the area of the A‐A' and B‐B' doublets decreases with the increasing heating time. However, the area of C‐C' keeps almost constant. Therefore, the 4 sets of doublets can be assigned correctly as follows: A‐A' doublet to Fe⁺²at M1, B‐B' Fe²⁺at M1, C‐C' Fe²⁺at M2, and D‐D' Fe³⁺at M1. The M1 site splitting is due to the NNN (Next Nearest Neighbour) effect of the M2 site. The amount of Fe³⁺at the tetrohedral site of megacrystal clinopyroxene is negligible according to this study.  相似文献   

Partial melting in the Inzie Head gneisses: the role of water and a petrogenetic grid in KFMASH applicable to anatectic pelitic migmatites   总被引：5，自引：0，他引：5  

T. E. Johnson  N. F. C. Hudson  G. T. R. Droop 《Journal of Metamorphic Geology》2001,19(1):99-118

A sequence of prograde isograds is recognized within the Dalradian Inzie Head gneisses where pelitic compositions have undergone variable degrees of partial melting via incongruent melting reactions consuming biotite. Three leucosome types are identified. At the lowest grades, granitic leucosomes containing porphyroblasts of cordierite (CRD‐melt) are abundant. At intermediate grades, CRD‐melt mingles with garnetiferous leucosomes (GT‐melt). At the highest grades, CRD‐melt coexists with orthopyroxene‐bearing leucosomes (OPX‐melt), while garnet is conspicuously absent. The prograde metamorphic field gradient is constrained to pressures of 2–3 kbar below the CRD‐melt isograd, and no greater than 4.5 kbar at the highest grade around Inzie Head. A petrogenetic grid, calculated using thermocalc , is presented for the K₂O–FeO–MgO–Al₂O₃–SiO₂–H₂O (KFMASH) system for the phases orthopyroxene, garnet, cordierite, biotite, sillimanite, H₂O and melt with quartz and K‐feldspar in excess. For the implied field gradient, the reaction sequence predicted by the grid is consistent with the successive prograde development of each leucosome type. Compatibility diagrams suggest that, as anatexis proceeded, bulk compositions may have been displaced towards higher MgO content by the removal of (relatively) ferroan granitic leucosome. An isobaric (P = 4 kbar) T–a_H2O diagram shows that premigmatization fluids must have been water‐rich (a_H2O > 0.85) and suggests that, following the formation of small volumes of CRD‐melt, the system became fluid‐absent and melting reactions buffered a_H2O to lower values as temperatures rose. GT‐ and OPX‐melt formed by fluid‐absent melting reactions, but a maximum of 7–11% CRD‐melt fraction can be generated under fluid‐absent conditions, much less than the large volumes observed in the field. There is strong evidence that the CRD‐melt leucosomes could not have been derived by buoyantly aided upwards migration from levels beneath the migmatites. Their formation therefore required a significant influx of H₂O‐rich fluid, but in a quantity insufficient to have exhausted the buffering capacity of the solid assemblage plus melt. Fluid : rock ratios cannot have exceeded 1 : 30. The fluid was channelled through a regionally extensive shear zone network following melt‐induced failure. Such an influx of fluid at such depths has obvious consequences for localized crustal magma production and possibly for cordierite‐bearing granitoids in general.  相似文献