scholarly journals Determination of long-term changes in the Earth's gravity field from satellite laser ranging observations

1997 ◽  
Vol 102 (B10) ◽  
pp. 22377-22390 ◽  
Author(s):  
M. K. Cheng ◽  
C. K. Shum ◽  
B. D. Tapley
Keyword(s):  
Gravity Field ◽  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
Earth’S Gravity Field ◽  
Long Term Changes

scholarly journals Analysis of the Results of the Borowiec SLR Station (7811) for the Period 1993–2019 as an Example of the Quality Assessment of Satellite Laser Ranging Stations

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 616
Author(s):  
Stanisław Schillak ◽  
Paweł Lejba ◽  
Piotr Michałek ◽  
Tomasz Suchodolski ◽  
Adrian Smagło ◽  
...  
Keyword(s):  
Satellite Laser Ranging ◽  
Laser Ranging ◽  
High Compliance ◽  
Long Term Stability ◽  
Factors Influencing ◽  
Very High ◽  
Orbital Analysis

This paper presents the results of an orbital analysis of satellite laser ranging data performed by the Borowiec SLR station (7811) in the period from July 1993 to December 2019, including the determination of the station positions and velocity. The analysis was performed using the GEODYN-II orbital program for the independent monthly orbital arcs from the results of the LAGEOS-1 and LAGEOS-2 satellites. Each arc was created from the results of the laser observations of a dozen or so selected stations, which were characterized by a large number of normal points and a good quality of observations. The geocentric and topocentric coordinates of the station were analyzed. Factors influencing the uncertainty of the measurements were determined: the number of the normal points, the dispersion of the normal points in relation to the orbits, and the long-term stability of the systematic deviations. The position leap at the end of 2002 and its interpretation in ITRF2014 were analyzed. The 3D stability of the determined positions throughout the period of study was equal to 12.7 mm, with the uncertainty of determination being at the level of 4.3 mm. A very high compliance of the computed velocity of the Borowiec SLR station (24.9 mm/year) with ITRF2014 (25.0 mm/year) was found.

Determination of Polar Motion and Earth Rotation from Laser Tracking of Satellites

1979 ◽  
Vol 82 ◽  
pp. 231-238 ◽  
Author(s):  
David E. Smith ◽  
Ronald Kolenkiewicz ◽  
Peter J. Dunn ◽  
Mark Torrence
Keyword(s):  
Gravity Field ◽  
Radiation Pressure ◽  
Orbit Determination ◽  
Earth Rotation ◽  
Polar Motion ◽  
Ocean Tides ◽  
Earth’S Gravity Field ◽  
Laser Tracking ◽  
Order Of Magnitude

Laser tracking of the Lageos spacecraft has been used to derive the position of the Earth's pole of rotation at 5-day intervals during October, November and December 1976. The estimated precision of the results is 0.01 to 0.02 arcseconds in both x and y components, although the formal uncertainty is an order of magnitude better, and there is general agreement with the Bureau International de l'Heure smoothed pole path to about 0.02 arcseconds. Present orbit determination capability of Lageos is limited to about 25 cm rms fit to data over periods of 5 days and about 50 cm over 50 days. The present major sources of error in the perturbations of Lageos are Earth and ocean tides followed by the Earth's gravity field, and solar and Earth reflected radiation pressure. Ultimate accuracy for polar motion and Earth rotation from Lageos after improved modeling of the perturbing forces appears to be of order ± 5 cm for polar motion over a period of about 1 day and about ± 0.2 to ± 0.3 milliseconds in U.T. for periods up to 2 or 3 months.

Long-term changes in weed occurrence, yield and use of herbicides in maize in south-western Germany, with implications for the determination of economic thresholds

Weed Research ◽  
2014 ◽  
Vol 54 (5) ◽  
pp. 457-466 ◽  
Author(s):  
M Keller ◽  
N Böhringer ◽  
J Möhring ◽  
V Rueda-Ayala ◽  
C Gutjahr ◽  
...  
Keyword(s):  
Economic Thresholds ◽  
Long Term Changes ◽  
Western Germany

scholarly journals Long-term changes and maintenance of Phyllitis scolopendrium (L.) Newman population in the Wodąca Valley (the Cracow-Częstochowa Upland)

2011 ◽  
Vol 23 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Stanisław Wika ◽  
Alicja Barć
Keyword(s):  
Association Studies ◽  
Long Term Changes ◽  
Quantitative Changes ◽  
Scientific Arguments

Long-term changes and maintenance of Phyllitis scolopendrium (L.) Newman population in the Wodąca Valley (the Cracow-Częstochowa Upland) The Cracow-Częstochowa Upland is an important mesoregion for the maintenance of Phyllitis scolopendrium (L.) Newman and its habitat with the Phyllitido-Aceretum Moor 1952 association. Studies in the Wodąca Valley focused on: the determination of the actual numerical force and quantitative changes in hart's-tongue resources between 1999 and 2009, a comparison of these results with literature, as well as on the indication of appropriate solutions for conservation purposes and for tourist exploitation of the Jurassic outcrops. Results of these studies provide scientific arguments for the maintenance of Phyllitis scolopendrium in the Wodąca Valley, on the edge of its European range.

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