1999年与2003年我国北方地区夏季气温异常原因初探   总被引：2，自引：0，他引：2       下载免费PDF全文

王作东  杨青  宫焕盛  孙莹  卢秉红 《气象与环境学报》2006,22(5):6-9

分析了1999年与2003年我国北方地区夏季气温的变化特点和同期大气环流主要特征。结果表明:中国夏季气温变化有明显的年代际特征,这一特征与亚洲上空大气环流的年代际变化紧密相关,表明我国北方地区夏季气温异常一个很重要的原因或许是缘于气候年代际变化。2003年夏季中高纬环流形势呈两槽两脊的配置,与近十几年气候态分布刚好相反,因而从气候年代际变化的特征来看,2003年为预示年代际气候转型的征兆。  相似文献   

Analysis of the Decadal and Interdecadal Variations of the East Asian Winter Monsoon as Simulated by 20 Coupled Models in IPCC AR4     

HE Shengping  WANG Huijun 《Acta Meteorologica Sinica》2012,26(4):476-488

Using the output data of 20 coupled climate models used in IPCC AR4 and observational data from NCEP, the capability of the models to simulate the boreal winter climatology of the East Asian sea level pressure, 850-hPa wind, and surface air temperature; the decadal variations of the East Asian winter mon- soon (EAWM) intensity and EAWM-related circulation, and the interdecadal variations of EAWM-related circulation are systematically evaluated. The results indicate that 16 models can weakly simulate the declin- ing trend of the EAWM in the 1980s. More than half of the models produce relatively reasonable decadal variations of the EAWM-related circulation and the interdecadal di?erences of EAWM-related circulation between the boreal winters of 1960-1985 and 1986-1998, including the weakened Siberian high, Aleutian low, and East Asian trough, the enhanced Arctic oscillation and North Pacific oscillation, and a deepened polar vortex. It is found that the performance of the multi-selected-model ensemble in reproducing the spatial dis- tribution of the variations is encouraging, although the variational amplitudes are generally smaller than the observations. In addition, it is found that BCCR_BCM2.0, CGCM3.1_T63, CNRM_CM3, CSIRO_MK3.0, GISS-ER, INM_CM3.0, and MRI_CGCM2.3.2 perform well in every aspect  相似文献   

山区年、月平均温度推算方法的研究   总被引：9，自引：0，他引：9  

卢其尧 《地理学报》1988,(3)

本文提出了山区年、月平均温度空间分布的推算方法,并提供了相应的小地形温度订正值。该方法在福建省沙溪流域山区实际应用的结果表明,能有效地揭示山区年、月平均温度空间分布的宏观与微观变化,效果满意,精度较高。  相似文献   

Microseismicity in a flooded potash mine,the Hope mine,Federal Republic of Germany     

C. Heick  D. Flach 《Pure and Applied Geophysics》1989,129(3-4):475-496

Measuring of microseismic events has been carried out at the former potash mine of Hope since early 1984.Analysis of the data demonstrates an immediate temporal relationship between brine introduction and onset of microseismic activity. The spatial distribution of the sources indicates a dependence on brine level height. Sources are found preferentially immediately next to roads and workings. Source radii, estimated from the frequency ranges in the seismograms, varied with the cross-section of neighbouring cavities and had a similar, order of size.Events occurred rarely in the previously flooded mine sections Similarly, the zone below a depth of approx. 600 m below sea level was virtually inactive.  相似文献   

大厂锡矿的成矿流体   总被引：8，自引：2，他引：8  

李荫清  陈伟十 《岩石学报》1989,5(3):12-24

本文详细研究了矿带内流体包裹体特征,测定了不同类型包裹体在冷热状态下相的转变点温度,利用有关的NaCl-H_2O体系、CO_2-NaCl-H_2O体系相图获得了矿带内不同类型矿床成矿的温度、压力等物理、化学参数。通过包裹体成分和同位素研究,阐明了成矿流体的性质、来源及其演化特征,探讨了成矿流体的沸腾和不混溶作用以及它们对成矿所作的贡献。估测了矿化深度和盲矿体存在的可能性。  相似文献   

Modeling long term lake variations by physically based stochastic dynamic models     

V. E. Privalsky 《Stochastic Environmental Research and Risk Assessment (SERRA)》1988,2(4):303-315

Several physically based stochastic dynamic models (SDM) are described including year-to-year variations of water volume in terminal and non-terminal lakes, streamflow of lake-fed rivers, and salinity of an inland sea (the Sea of Azov). All of these models are based upon the SDM of water volume of terminal lakes developed by Kritzky and Menkel in 1946 in co-operation with Kolomogorov. Explicit formulae are derived for second order statistical moments of the output processes, including variance, correlation function, spectra, etc., under the assumption that the forcing functions from stationary random sequences. The least-squares prediction problem is solved for both stationary and non-stationary cases. Some of the processes are shown to possess high statistical predictability. Actual predictions are compared with independent observations. Problems for further study are stated.  相似文献   

A thermo-plastic constitutive law for brittle-plastic behavior of rocks at high temperatures     

Tomasz Hueckel  Alberto Peano  Rita Pellegrini 《Pure and Applied Geophysics》1994,143(1-3):483-510

Mechanical properties of rocks change under the influence of, temperature. Stress at the onset of yielding, ultimate strength, dilatancy, strain hardening and softening, and the confining pressure at brittle-ductile transition are all reduced by the increasing temperature. This study presents a framework of constitutive modeling of thermo-brittle-plastic behavior of rocks which encompasses these changes. The constitutive law is based on a thermo-plasticity theory first proposed for metals byPrager (1958). Two phenomenological mechanisms have been identified as central for the modeling: temperature dependence of the yield locus (thermal softening), and temperature dependence of the strain-hardening function (thermally enhanced ductility). Material parameters for two rocks, Carrara marble and Westerly granite, were determined on the basis of additional hypotheses. These parameters are used in numerical simulations of triaxial tests at different temperatures. The obtained stress-strain curves compare well to the experimental results. The changes with temperature in the stress at the onset of yielding are more accurately reproduced that the evolution of hardening or softening. Suggestions for possible improvements and future research directions are indicated.  相似文献   

Historical changes in sediments of Pyramid Lake,Nevada, USA: consequences of changes in the water balance of a terminal desert lake   总被引：1，自引：0，他引：1  

Martin E. Lebo  John E. Reuter  Philip A. Meyers 《Journal of Paleolimnology》1994,12(2):87-101

Sediment cores from the shallow and deep basins of Pyramid Lake, Nevada, revealed variations in composition with depth reflecting changes in lake level, river inflow, and lake productivity. Recent sediments from the period of historical record indicate: (1) CaCO₃ and organic content of sediment in the shallow basin decrease at lower lake level, (2) CaCO₃ content of deep basin sediments increases when lake level decreases rapidly, and (3) the inorganic P content of sediments increases with decreasing lake volume. Variations in sediment composition also indicate several periods for which productivity in Pyramid Lake may have been elevated over the past 1000 years. Our data provide strong evidence for increased productivity during the first half of the 20th Century, although the typical pattern for cultural eutrophication was not observed. The organic content of sediments also suggests periods of increased productivity in the lake prior to the discovery and development of the region by white settlers. Indeed, a broad peak in organic fractions during the 1800's originates as an increase starting around 1600. However, periods of changing organic content of sediments also correspond to periods when inflow to the lake was probably at extremes (e.g. drought or flood) indicating that fluctuations in river inflow may be an important factor affecting sediment composition in Pyramid Lake.  相似文献   

On the detectability of a highly conductive layer in the upper mantle beneath the Black Forest crystalline using magnetotelluric methods     

Bülent Tezkan 《Geophysical Journal International》1994,118(1):185-200

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太阳活动,大气臭氧和平流层温度相关分析研究   总被引：1，自引：4，他引：1  

言穆弘  华贵义 《高原气象》1993,12(3):302-311

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