The mapping of Kaula's solution into the orbital reference frame     

Stefano Casotto 《Celestial Mechanics and Dynamical Astronomy》1993,55(3):223-241

Kaula's celebrated solution to the problem of satellite motion in the gravitational field of a rigid body is transformed to give the perturbation spectra in both position and velocity in the radial, transverse and normal directions of the orbital reference frame. This work is an extension and a refinement of the theory of orbital perturbations due to the geopotential previously published by Rosborough and Tapley (1987).  相似文献   

Analytical linear perturbation theory for highly eccentric satellite orbits     

Eugene Brumberg  Victor A. Brumberg  Thomas Konrad  Michael Soffel 《Celestial Mechanics and Dynamical Astronomy》1995,61(4):369-387

Kaula's satellite linear perturbation theory has been extended for the case of highly eccentric orbits by using elliptic function expansions.On leave from Institute of Applied Astronomy, St.-Petersburg  相似文献   

Impact of an extreme melt event on the runoff and hydrology of a high Arctic glacier     

Sarah Boon  Martin Sharp  Peter Nienow 《水文研究》2003,17(6):1051-1072

On 28–30 July 2000, an extreme melt event was observed at John Evans Glacier (JEG), Ellesmere Island (79° 40′N, 74° 00′W). Hourly melt rates during this event fell in the upper 4% of the distribution of melt rates observed at the site during the period 1996–2000. Synoptic conditions during the event resulted in strong east‐to‐west flow over the northern sector of the Greenland Ice Sheet, with descending flow on the northwest side reaching Ellesmere Island. On JEG, wind speeds during the event averaged 8·1 m s^?1 at 1183 m a.s.l., with hourly mean wind speeds peaking at 11·6 m s^?1. Air temperatures reached 8°C, and rates of surface lowering measured by an ultrasonic depth gauge averaged 56 mm day^?1. Calculations with an energy balance model suggest that increased turbulent fluxes contributed to melt enhancement at all elevations on the glacier, while snow albedo feedback resulted in increased melting due to net radiation at higher elevations. The event was responsible for 30% of total summer melt at 1183 m a.s.l. and 15% at 850 m a.s.l. Conditions similar to those during the event occurred on only 0·1% of days in the period 1948–2000, but 61% of events occurred in the summer months and there was an apparent clustering of events in the 1950s and 1980s. Such events have the potential to impact significantly on runoff, mass balance and drainage system development at high Arctic glaciers, and changes in their incidence could play a role in determining how high Arctic glaciers respond to climate change and variability. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

用SLR数据导出的地心运动结果   总被引：2，自引：0，他引：2  

秦显平  杨元喜 《测绘学报》2003,32(2):120-124

在利用卫星激光测距(Satellite Laser Ranging，简称SLR)资料研究地心运动时，将抗差估计和方差分量估计引入列数据处理中，根据1996年1月至2000年12月的Lageos2观测数据，分别采用直接法和动力法，计算出了2组相对于ITRF2000参考框架原点的地心运动序列。对计算结果进行了分析，得出了地心运动的平均值、变化速率及其周年项、半年项的振幅和相位，并与其他采用SLR资料计算的结果进行了比较。通过比较和分析，发现地心运动存在着近周年和近半年的周期分量，但地心运动的长期变化并不明显。  相似文献   

卫星云图和数值产品结合的讯期强降水预警系统   总被引：1，自引：5，他引：1  

魏建苏  严明良等 《气象科学》2001,21(3):355-362

本文采用卫星云图分析和数值产品释用相结合的技术路线，对汛期强降水在红外云图、水汽图、可见光云图上的特征从形态学、统计学等方面进行了研究，获得了汛期强降水云团的特征结构，并结合数值预报产品，建立了汛期强降水云团预警系统。  相似文献   

Accurate absolute GPS positioning through satellite clock error estimation   总被引：11，自引：0，他引：11  

S.-C. Han  J. H. Kwon  C. Jekeli 《Journal of Geodesy》2001,75(1):33-43

 An algorithm for very accurate absolute positioning through Global Positioning System (GPS) satellite clock estimation has been developed. Using International GPS Service (IGS) precise orbits and measurements, GPS clock errors were estimated at 30-s intervals. Compared to values determined by the Jet Propulsion Laboratory, the agreement was at the level of about 0.1 ns (3 cm). The clock error estimates were then applied to an absolute positioning algorithm in both static and kinematic modes. For the static case, an IGS station was selected and the coordinates were estimated every 30 s. The estimated absolute position coordinates and the known values had a mean difference of up to 18 cm with standard deviation less than 2 cm. For the kinematic case, data obtained every second from a GPS buoy were tested and the result from the absolute positioning was compared to a differential GPS (DGPS) solution. The mean differences between the coordinates estimated by the two methods are less than 40 cm and the standard deviations are less than 25 cm. It was verified that this poorer standard deviation on 1-s position results is due to the clock error interpolation from 30-s estimates with Selective Availability (SA). After SA was turned off, higher-rate clock error estimates (such as 1 s) could be obtained by a simple interpolation with negligible corruption. Therefore, the proposed absolute positioning technique can be used to within a few centimeters' precision at any rate by estimating 30-s satellite clock errors and interpolating them. Received: 16 May 2000 / Accepted: 23 October 2000  相似文献   

Spherical Tikhonov regularization wavelets in satellite gravity gradiometry with random noise     

W. Freeden  S. Pereverzev 《Journal of Geodesy》2001,74(10):730-736

 A special class of regularization methods for satellite gravity gradiometry based on Tikhonov spherical regularization wavelets is considered, with particular emphasis on the case of data blurred by random noise. A convergence rate is proved for the regularized solution, and a method is discussed for choosing the regularization level a posteriori from the gradiometer data. Received: 23 March 2000 / Accepted: 20 September 2000  相似文献   

The Atmospheric Boundary-Layer Structure Within A Cold Air Outbreak: Comparison Of In Situ, Lidar And Satellite Measurements With Three-Dimensional Simulations     

Cyrille Flamant  Marc Georgelin  Laurent Menut  Jacques Pelon  Philippe Bougeault 《Boundary-Layer Meteorology》2001,99(1):85-103

A cold-air outbreak over the Mediterranean, associated with a Tramontane event, has been simulated with the atmospheric non-hydrostatic model Meso-NH using a horizontal resolution of 2 km. Results are compared with in situ aircraft, airborne lidar and satellite measurements. On average, the mean and turbulent parameters simulated in the surface layer and mixed layer compared well with in situ measurements. The model was able to reproduce accurately the Foehn effect in the wake of Cape Creus, as well as the occurence of rolls in the coastal region in connection with cloud streets observed with AVHRR. Over the sea, the threshold value of turbulent kinetic energy defining the height of the atmospheric boundary-layer top in the model (defined as 25% of the maximum turbulent kinetic energy in the profile) enables the simulated atmospheric boundary-layer height to match the one retrieved from lidar measurements. Nevertheless, the model did not handle very well the abrupt gradients of all meteorological parameters observed at the top of the atmospheric boundary-layer. Reasons for this are investigated.  相似文献   

Precise Orbit Determination With Slr: Setting The Standard     

Ron Noomen 《Surveys in Geophysics》2001,22(5-6):473-480

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青藏高原东北隅弧束断裂与南鄂尔多斯环形构造   总被引：7，自引：0，他引：7       下载免费PDF全文

李建华  申旭辉 《地震地质》2001,23(1):116-121

卫星图像分析显示 ,青藏高原东北隅存在非常清晰的毛毛山 -南华山 -六盘山、香山 -天景山、烟筒山、牛首山 -罗山 4条弧形断裂带和南鄂尔多斯环形构造。分析了弧形构造的运动特征和南鄂尔多斯环形构造的形态 ,认为青藏高原东北隅弧束断裂的成因是印度板块向NNE俯冲导致青藏高原NEE向移动所产生的推挤力 ,受到南鄂尔多斯环形构造的阻挡 ,形成了 4条向固原、泾原收敛 ,向NWW、NW方向撒开的弧束断裂。造成撒开部分NWW—NNW向断裂左旋走滑、NW—SN向断裂右旋走滑、收敛部分逆冲挤压的特  相似文献