HUBEX试验期间地基微波辐射计反演资料的应用研究   总被引：2，自引：0，他引：2  

李万彪  刘盈辉  朱元竞  赵柏林 《气候与环境研究》2001,6(2):203-208

在1998年和1999年淮河流域能量和水循环试验(HUBEX)加密观测期间(IOPs),获得了双通道微波辐射计观测资料反演得到的大气水汽含量和云中液态水含量的时间连续资料序列.本文结合天气分析和其他加密观测资料,进行了HUBEX试验期间天气变化同大气水分变化关系的分析.结果表明,天气条件的变化是大气水分变化的主要原因.  相似文献   

用GMS-5卫星资料结合地面资料联合估算水汽分布   总被引：8，自引：2，他引：6  

姚展予  袁健  李万彪  朱元竞  赵柏林 《气候与环境研究》2001,6(2):197-202

利用GMS-5卫星红外分裂窗通道和水汽通道结合探空资料反演晴空大气的水汽分布;同时利用探空资料建立地面水汽压和相对湿度与大气总水汽量的经验关系,通过带权插值生成淮河流域300多个地面站经验关系式的系数矩阵,并利用地面站资料确定云天大气的水汽分布.最后,将两种方法进行融合,得到淮河流域全天候的水汽场分布.  相似文献   

ANALYSIS ON CHARACTERISTICS OF ATMOSPHERIC DUCT AND ITS EFFECTS ON THE PROPAGATION OF ELECTROMAGNETIC WAVE   总被引：1，自引：0，他引：1  

姚展予  赵柏林  李万彪  朱元竞  杜金林  戴福山 《Acta Meteorologica Sinica》2001,(2)

On the basis of introducing the basic categories of atmospheric refraction and their existingconditions,the forming processes of three kinds of atmospheric ducts are expounded.Several maincharacteristics of atmospheric duct are summarized and analyzed,and field sounding data from theWEstern North-Pacific cloud-radiation EXperiment(WENPEX)and meteorological data aroundthe Xisha sea area are used to validate these characteristics.Meanwhile the sensitivities of theevaporation duct height to the variations of atmospheric humidity.the air-sea temperaturedifference.and horizontal wind speed are examined.With the analysis of the effect of atmosphericduct on the propagation of electromagnetic wave.the maximum trapped-wavelength and the criticalemitting angle of elevation for electromagnetic wave which can form duct propagation are derived.At the same time the four kinds of necessary conditions for electromagnetic wave to form ductpropagation are brought forward.The effects of atmospheric duct on ultrashort wave propagation,radar observation.short wave communication etc.are also discussed.  相似文献   

LABORATORY STUDY ON MICROWAVE REMOTE SENSING OF GROUND TRUTH^*     

Zhao Bolin  Zhao Wenzhong  Han Qingyuan 《Acta Meteorologica Sinica》1991,5(3):317-330

In order to improve the interpretation of the earth system microwave remote sensing,the research of microwave spectrum characteristics of the ground truth (earth objects) was carried out in laboratory.A laboratory for microwave remote sensing of the earth objects has been constructed to improve the remote sensing level,the laboratory consists of four parts:the measuring system of dielectric constants,the microwave emissivity meter,the microwave reflectometer and the microwave remote sensing simulation experiment in field.In this paper,the principle of measurement,the correction of near field process,the structure of instrument,the calibration method and the measurement of the earth substances,including soil,water and oil,are discussed.The laboratory may supply the condition for measuring the parameters of thc earth substance remote sensing and help to interpret the remote sensing data.  相似文献   

Manganese fluxes from Mississippi Delta sediments     

John H. Trefry  Bob J. Presley 《Geochimica et cosmochimica acta》1982,46(10):1715-1726

Massive sediment deposition on the Mississippi River Delta establishes reducing conditions sufficient to bring about Mn dissolution in the top millimeters of sediment. As a result, significant fluxes of dissolved Mn pass from the Delta sediments to the overlying water column. This process is examined by study of chemical partitioning of Mn in river particulates and Delta sediments and from interstitial water chemistry. Remobilized Mn is actively transported away from the Delta area with aluminosilicate detritus thereby providing “excess” Mn to the deep Gulf of Mexico at the expense of the Delta sediments.  相似文献   

Thallium: a sensitive indicator of rock/seawater interaction and of sulfur saturation of silicate melts     

Peter J. McGoldrick  Reid R. Keays  Bob B. Scott 《Geochimica et cosmochimica acta》1979,43(8):1303-1311

Radiochemical neutron activation analysis for Tl in a number of young pillow basalts, hydrothermally altered basalts and associated hydrothermal and hydrogenous Mn crusts from the Mid-Atlantic Ridge and adjacent regions of the North Atlantic indicate that Tl is a sensitive indicator of both S saturation of silicate melts and of rock/seawater interactions. Rb-Cs-K-Tl trend lines for fresh MAR basalts (whose melts remained saturated with S during silicate fractionation) are distinctly different to Hawaiian basalts whose melts lost S during or prior to eruption, but were saturated with S at an earlier stage. Varying degrees of Tl enrichment are found in the hydrogenous Mn nodules (91,000 ppb), hydrothermal Mn crusts (2300–32,000 ppb), palagonitized glass (300–2700 ppb), hydrothermally altered basalts (1140–4560 ppb), and even slightly altered pillow interiors (11–45 ppb) relative to the fresh glasses (6–12 ppb). This enrichment has taken place due to incorporation of Tl into secondary silicate phases along with the alkalis and also due to co-precipitation of Tl with ferromanganese oxides and hydroxides. Thallium enrichment in the hydrothermal products is interpreted as being due to cooling and oxidation of hydrothermal fluids as these approached the sea floor. Haloes of Tl-enriched country rock may occur around sulfide deposits in which seawater has acted as the ore fluid.  相似文献   

冀东太平寨地区麻粒岩及有关岩石的辉石研究          下载免费PDF全文

张儒瑗  从柏林  应育浦 《地质科学》1982,(2):134-143

冀东早太古代迁西群是由火山-沉积岩系变质生成的一套变质杂岩。它的主体是麻粒岩类以及退变质生成的斜长角闪岩类的岩石。该套变质岩系的下部夹有层状和透镜状变质超镁铁质岩(变橄辉岩、变辉橄岩、变辉石岩及变闪辉岩),而上部为变质的含铁岩系。以石渣子山和娄子山为例,它们的含铁岩层分别为辉石磁铁石英岩和英榴易熔岩。 本区的麻粒岩和斜长角闪岩在岩相学上呈渐变关系。绝对不含角闪石和/或富钛黑云母的麻粒岩是很少的。本文将以角闪石和斜长石为主要组成矿物的岩石归为斜长角闪岩类。在斜长角闪岩类岩石中,角闪石含量大大超过辉石,另外常见被角闪石交代的辉石残晶。  相似文献   

Spatial Variability of Turbulent Fluxes in the Roughness Sublayer of an Even-Aged Pine Forest   总被引：1，自引：1，他引：0  

Gabriel Katul  Cheng-I Hsieh  David Bowling  Kenneth Clark  Narasinha Shurpali  Andrew Turnipseed  John Albertson  Kevin Tu  Dave Hollinger  Bob Evans  Brian Offerle  Dean Anderson  David Ellsworth  Chris Vogel  Ram Oren 《Boundary-Layer Meteorology》1999,93(1):1-28

The spatial variability of turbulent flow statistics in the roughness sublayer (RSL) of a uniform even-aged 14 m (= h) tall loblolly pine forest was investigated experimentally. Using seven existing walkup towers at this stand, high frequency velocity, temperature, water vapour and carbon dioxide concentrations were measured at 15.5 m above the ground surface from October 6 to 10 in 1997. These seven towers were separated by at least 100m from each other. The objective of this study was to examine whether single tower turbulence statistics measurements represent the flow properties of RSL turbulence above a uniform even-aged managed loblolly pine forest as a best-case scenario for natural forested ecosystems. From the intensive space-time series measurements, it was demonstrated that standard deviations of longitudinal and vertical velocities (_u, _w) and temperature (_T) are more planar homogeneous than their vertical flux of momentum (u_* ²) and sensible heat (H) counterparts. Also, the measured H is more horizontally homogeneous when compared to fluxes of other scalar entities such as CO₂ and water vapour. While the spatial variability in fluxes was significant (>15 %), this unique data set confirmed that single tower measurements represent the canonical structure of single-point RSL turbulence statistics, especially flux-variance relationships. Implications to extending the moving-equilibrium hypothesis for RSL flows are discussed. The spatial variability in all RSL flow variables was not constant in time and varied strongly with spatially averaged friction velocity u_*, especially when u_* was small. It is shown that flow properties derived from two-point temporal statistics such as correlation functions are more sensitive to local variability in leaf area density when compared to single point flow statistics. Specifically, that the local relationship between the reciprocal of the vertical velocity integral time scale (I_w) and the arrival frequency of organized structures (/h) predicted from a mixing-layer theory exhibited dependence on the local leaf area index. The broader implications of these findings to the measurement and modelling of RSL flows are also discussed.  相似文献   

ESTIMATION OF CLOUD LIQUID WATER OVER THE HUBEX AREA USING THE TRMM MICROWAVE IMAGER     

YAO Zhanyu  Li Wangbiao  Zhu Yuanjing  Zhao Bolin 《Acta Meteorologica Sinica》2002,16(3):309-316

The ability of the Tropical Rainfall Measuring Mission Microwave Imager(TRMM/TMI)forcloud liquid water(CLW)retrieval has been demonstrated in this study.Due to the greatsensitivity of the TMI 85.5 GHz channels to CLW,the liquid water path(LWP)ofnonprecipitating clouds over land can be successfully estimated using the VDISORT model basedon the iteration steps.Both the vertical-polarized 85. 5 GHz single-channel method and thepolarization-difference of 85.5 GHz method were applied to the LWP estimates over land regionsduring the Huaihe River Basin Energy and Water Cycle Experiment(HUBEX)in China.Theretrieval results show reasonable agreement with the ground-based microwave radiometermeasurements.When the surface emissivity or skin temperature is difficult to be made sure,thepolarization-difference method shows advantages of providing estimates of LWP especially for lowclouds because of its extremely insensitiveness to the surface skin temperature.  相似文献   

A Sensitivity Analysis of Timing and Costs of Greenhouse Gas Emission Reductions   总被引：1，自引：0，他引：1  

Reyer Gerlagh  Bob van der Zwaan 《Climatic change》2004,65(1-2):39-71

This paper analyses the optimal timing and macro-economic costs of carbon emission reductions that mitigate the global average atmospheric temperature increase. We use a macro-economic model in which there are two competing energy sources, fossil-fuelled and non-fossil-fuelled. Technological change is represented endogenously through learning curves, and niche markets exist implying positive demand for the relatively expensive non-fossil-fuelled energy source. Under these conditions, with a temperature increase constraint of 2 ° C, early abatement is found to be optimal, and, comparedto the results of many existing top-down models, the costs of this strategy prove to be low. We perform an extensive sensitivity analysis of our results regarding the uncertainties that dominate various economic and technological modeling parameters. Uncertainties in the learning rate and the elasticity of substitution between the two different energy sources most significantly affect the robustness of our findings.  相似文献