Surface roughness length dynamic over several different surfaces and its effects on modeling fluxes     

《中国科学D辑(英文版)》2006,(Z2)

Roughness length and zero-plane displacement over three typical surfaces were calculated iteratively by least-square method, which are Yucheng Experimental Station for agriculture surfaces, Qianyanzhou Experimental Station for complex and undulant surfaces, and Changbai Mountains Experimental Station for forest surfaces. On the basis of roughness length dynamic, the effects of roughness length dynamic on fluxes were analyzed with SEBS model. The results indicate that, aerodynamic roughness length changes with vegetation conditions (such as vegetation height, LAI), wind speed, friction velocity and some other factors. In Yucheng and Changbai Mountains Experimental Station, aerodynamic roughness length over the fetch of flux tower changes with vegetation height and LAI obviously, that is, with the increase of LAI, roughness length increases to the peak value firstly, and then decreases. In Qianyanzhou Experimental Station, LAI changes slightly, so the relationship between roughness length and LAI is not obvious. The aerodynamic roughness length of Yucheng and Changbai Mountains Experimental Station changes slightly with wind direction, while aerodynamic roughness length of Qianyanzhou Experimental Station changes obviously with wind direction. The reason for that is the terrain in Yucheng and Changbai Mountains Experimental Station is relatively flat, while in Qianyanzhou Experimental Station the terrain is very undulant and heterogeneous. With the increase of wind speed, aerodynamic roughness length of Yucheng Experimental Station changes slightly, while it decreases obviously in Qianyanzhou Experimental Station and Changbai Mountains Experimental Station. Roughness length dynamic takes great effects on fluxes calculation, and the effects are analyzed by SEBS model. By comparing 1 day averaged roughness length in Yucheng Experimental Station and 5 day averaged roughness length of Qianyanzhou and Changbai Mountains Experimental Station with roughness length parameter chosen by the model, the effects of roughness length dynamic on flux calculation is analyzed. The maximum effect of roughness length dynamic on sensible heat flux is 2.726%, 33.802% and 18.105%, in Yucheng, Qianyanzhou, and Changbai Mountains experimental stations, respectively.  相似文献   

A new combined European permanent network station coordinates solution     

N. Panafidina  Z. Malkin  R. Weber 《Journal of Geodesy》2006,80(7):373-380

The EUREF [International Association of Geodesy (IAG) Reference Frame Sub-Commission for Europe] network of continuously operating GPS stations (EPN) was primarily established for reference frame maintenance, and also plays an important role for geodynamical research in Europe. The main objective of this paper is to obtain an independent homogeneous time series of the EPN station coordinates, which is also available in SINEX format. A new combined solution of the EPN station coordinates was computed. The combination was performed independently for every week, in three steps: (1) the stated constraints on the coordinates were removed from the individual solutions of the Analysis Centers; (2) the de-constrained solutions were aligned to ITRF2000; (3) the resulting solutions were combined using the Helmert blocking technique. All the data from GPS weeks 900 to 1302 (April 1997–December 2004) were used. We investigated in detail the behavior of the transformation parameters aligning the new combined solution to ITRF2000. In general, the time series of the transformation parameters show a good stability in time although small systematic effects can be seen, most likely caused by station instabilities. A comparison of the new combined solution to the official EUREF weekly combined solution is also presented.  相似文献   

南极长城站科考队员度夏期心功能的变化   总被引：2，自引：0，他引：2       下载免费PDF全文

邓希贤  薛全福  于永中  杨勇  刘文利  周晓梅 《极地研究》1998,10(3):72-77

中国第六次南极考察队长城站男性队员２８人分为两个年龄组：１组ｎ＝１７,３０．８±１．１岁;２组ｎ＝１１,４８．０±１．７岁。借助美国Ｂｏｍｅｄ公司ＮＣＣＯＭ－３型无创心功能监护仪对他们心功能的动态变化进行了检测,结果表明：所有受试者夏季在长城站短期停留和工作心功能均无明显变化,但低年龄组心脏的适应能力优于高年龄组。  相似文献   

南极中山站极夜、极昼期间S_q~p、S_D的变化规律及特征     

杨友华  刘春节  汪阳 《地震地磁观测与研究》1996,(2)

本文利用１９９１年度南极中山站的地磁资料，分析研究极夜（５、６、７月）及极昼（１１、１２月）期间Ｓ、ＳＤ的变化特征。研究结果表明，Ｈ、Ｄ、Ｚ三个分量的Ｓ、ＳＤ在极夜期间的变化幅度都小于极昼期间的变化幅度，Ｓ在世界时ＵＴ６时左右出现极值。这是由于在５、６、７月的太阳直射点在北半球，太阳紫外辐射和Ｘ射线辐射减少，在１１、１２月太阳的直射点在南半球，太阳紫外线和Ｘ射线辐射增大，致使空间电高层等效电流发生变化所产生。  相似文献   

On　the　problems　concerned　in“The　subter－ranean　electrical　conductivity　structure　at　the　ChineseGreatWalStationonAntarctic（CG┐WSA）”byXiaopingZeng，YunfangLinandYuechenZhao     

陈伯舫 《地震学报(英文版)》1996,(3)

Ｏｎｔｈｅｐｒｏｂｌｅｍｓｃｏｎｃｅｒｎｅｄｉｎ“Ｔｈｅｓｕｂｔｅｒ┐ｒａｎｅａｎｅｌｅｃｔｒｉｃａｌｃｏｎｄｕｃｔｉｖｉｔｙｓｔｒｕｃｔｕｒｅａｔｔｈｅＣｈｉｎｅｓｅＧｒｅａｔＷａｌＳｔａｔｉｏｎｏｎＡｎｔａｒｃｔｉｃ（ＣＧ┐ＷＳＡ）”ｂｙＸｉａｏ...  相似文献   

自由设站的高效测设技术研究     

杜晓梅  杨武 《四川测绘》1997,20(2):79-82,58

本文在开发研究全站型电子速测仪的专用功能的基础上，结合工程测施工放样的若干应用，提出了一系列自由设站的高效，实用的测设方法。  相似文献   

Atmospheric trace gas measurements at Palmer Station,Antarctica: 1982–83     

E. Robinson  W. L. Bamesberger  F. A. Menzia  A. S. Waylett  S. F. Waylett 《Journal of Atmospheric Chemistry》1984,2(1):65-81

In early 1982 a station capable of sampling atmospheric trace gas constituents on a continuous basis was established at Palmer Station, Anvers Island, adjacent to the Antarctic Peninsula (64° 46S 64° 04W). Sampling operations began about 1 February 1982. This is an initial report on this station, its location, equipment and general research objectives along with some initial sampling results. The constituents being measured and recorded were: ozone, methane, carbon dioxide, carbon monoxide, CCl₃F (fluorocarbon-11), CCl₂F₂ (fluorocarbon-12), carbontetrachloride, methylchloroform, nitrous oxide, and Aitken nuclei (CN). Data storage, data processing, and sampling system control is handled by a Hewlett-Packard 85 system. Preliminary analyses of about the first 20–22 months of data are presented and show not only the expected long-term trends but also shorter period concentration cycles that seem to be related to synoptic meteorology.  相似文献   

高速遥感多星通用格式化同步器的设计与实现     

陈星燎  陈金树  葛成辉 《遥感学报》2003,7(5):386-392

格式化同步器是卫星地面站的关键设备之一。本文利用快速发展的FPGA技术设计出了高速遥感多星通用格式化同步器，同时分析了若干关键技术参数及系统性能。该同步器可接收绝大部分国内外卫星，并且单机独立，集成度高，体积小，抗干扰能力强，与系统互联方便。  相似文献   

主动式集成GPS滑坡监测系统的研制与监测实践     

姜晨光  贺勇  刘玉荣  严立明  黄家兴 《四川测绘》2003,26(3):124-126

主动式集成GPS滑坡监测系统是GPS技术与电子全站仪技术的高度集成。本文叙述了主动式集成GPS滑坡监测系统的基本原理与工作过程。  相似文献   

Regional Sources of Methyl Chloride, Chloroform and Dichloromethane Identified from AGAGE Observations at Cape Grim, Tasmania, 1998–2000     

M. L. Cox  G. A. Sturrock  P. J. Fraser  S. T. Siems  P. B. Krummel  S. O'Doherty 《Journal of Atmospheric Chemistry》2003,45(1):79-99

There are large uncertainties in identifying and quantifying the natural and anthropogenic sources of chloromethanes – methyl chloride (CH₃Cl), chloroform (CHCl₃) and dichloromethane (CH₂Cl₂), which are responsible for about 15% of the total chlorine in the stratosphere. We report two years of in situ observations of these species from the AGAGE (Advanced Global Atmospheric Gas Experiment) program at Cape Grim, Tasmania (41° S, 145° E). The average background levels of CH₃Cl, CHCl₃ and CH₂Cl₂ during 1998–2000 were 551± 8, 6.3± 0.2 and 8.9± 0.2 ppt (dry air mole fractions expressed in parts per 10¹²) respectively, with a two-year average amplitude of the seasonal cycles in background air of 25, 1.1 and 1.5 ppt respectively. The CH₃Cl and CHCl₃ records at Cape Grim show clear episodes of elevated mixing ratios up to 1300 ppt and 55 ppt respectively, which are highly correlated, suggesting common source(s). Trajectory analyses show that the sources of CH₃Cl and CHCl₃ that are responsible for these elevated observations are located in coastal-terrestrial and/or coastal-seawater regions in Tasmania and the south-eastern Australian mainland. Elevated levels of CH₂Cl₂ (up to 70 ppt above background) are associated mainly with emissions from the Melbourne/Port Phillip region, a large urban/industrial complex (population 3.5 million) 300 km north of Cape Grim.Now at the Centre for Atmospheric ChemistryNow at School of Environmental Sciences  相似文献