Combined Sea Surface Determination Based on Various Geometric and Dynamic Techniques     

Erwin Groten  Tilman Muller 《Marine Geodesy》2013,36(3-4):185-195

Abstract

The combined use of Global Positioning System (GPS) differential positioning as well as ERS‐1 altimeter data is considered in implementing geodetic vertical datums and their unification. The article describes concepts, techniques, practical realization, and associated questions and problems. Particular aspects in view of small sea surface perturbations in offshore areas in determining sea surface components (variable and steady state) are discussed. The combinations of tide gauge data with altimetry and (mainly) GPS positioning for geodetic purposes are discussed in detail. Special attention is devoted to the associated reference systems as well as to the combination of dynamic (level and nonlevel surfaces) with geometric quantities. The discussion is based on a specific ERS‐1 project supported by the National Science Foundation. Implications and practical impact of the project are outlined.  相似文献   

An intercomparison of LaCoste and Romberg Model-D gravimeters: results of the International D-meter Campaign 1983     

M. Becker  E. Groten  A. Lambert  J. O. Liard  S. Nakai 《Geophysical Journal International》1987,89(2):499-526

  相似文献   

Absolute orientation of an astro-geodetic geoid section and its correlation with geophysical data     

Erwin Groten 《Studia Geophysica et Geodaetica》1970,14(2):212-221

  相似文献   

On the Upper Bound of the Liquid Core Viscosity     

Molodensky  S.M.  Groten  E. 《Studia Geophysica et Geodaetica》2001,45(1):12-36

By using Molodensky and Sasao (1995a) and Molodensky and Groten (1998) an approach of expansion in powers of the small parameter =(+)/ (where + and are the frequencies of nutational motion in space and in a mantle-fixed reference frame, respectively, is tidal frequency) a theory of diurnal Earth tides and nutation for a realistic model of the Earth with an inhomogeneous, viscous liquid core and an anelastic mantle is constructed. It is shown that our approach is self-consistent for semi-annual, annual, and principal nutational components (when ||1/180). By comparing the results of modern VLBI-nutational data and the results of our calculations, we have found the region of possible values of the parameters which describe the anelastic properties of the Earth's lower mantle and the viscosity of the liquid core. It is shown that modern VLBI-data are about six orders of magnitude more sensitive to the liquid core viscosity than modern seismic data or Earth free oscillations data.  相似文献   

Use of normalized metal concentrations in the Mn oxides/hydrous oxides extraction phase of stream sediments to enhance the difference between a landfill emission plume and background     

Erwin J. Mantei  Melida Gutierrez  Yia-Dong Zhou 《Applied Geochemistry》1996,11(6):803-810

Normalized concentrations of Fe, Zn, Ba and Co bound to the Mn phase were determined using a ratio of metal concentration to Mn concentration. Metal concentrations were taken from a previous study which found elevated concentrations of heavy metals in the stream sediments in the vicinity of 2 landfills using a HN0₃ extraction of the whole sediment sample and geochemical phases. Results from the normalized metal concentrations for Zn, Fe and Ba showed a clearer distinction between background and emission plume regions along the stream compared to the same for the HN0₃ and Mn phase extractions. Lack of elevated concentrations and normalized concentrations for Co indicated the concentrations represented the background. The small distance used in the study could explain the lack of a decreasing trend of metal concentrations and normalized metal concentrations downstream in the emission plume of the sediments. Although Mn⁺² 2concentrations are known to be incorporated into the natural state of the Mn phase, these concentrations were thought to be small enough not to influence the results from the normalized concentrations. Non-selectivity of extractants and metal redistribution among chemical phases during extraction procedures are thought to be small and did not invalidate the results.  相似文献   

Dependence of waterbirds and shorebirds on shallow-water habitats in the Mid-Atlantic coastal region: An ecological profile and management recommendations     

R. Michael Erwin 《Estuaries and Coasts》1996,19(2):213-219

Waterbirds (waterfowl, colonially nesting wading and seabirds, ospreys [Pandion haliaetus], and bald eagles [Haliaeetus leucocephalus]) and shorebirds (sandpipers, plovers, and relatives) may constitute a large fraction of the toplevel carnivore trophic component in many shallow-water areas of the mid-Atlantic region. The large biomass of many species (>1 kg body mass for the two raptors and some waterfowl) and enormous populations (e.g.,>1 million shorebirds in late May in parts of Delaware Bay) reveal the importance of waterbirds as consumers and as linkages in nutrient flux in many shallow-water habitats. Salt and brackish marsh shallow-water habitats, including marsh pannes and tidal pools and creeks as well as constructed impoundments, are used intensively during most months of the year; in fall and winter, mostly by dabbling ducks, in spring and summer by migrant shorebirds and breeding colonial wading birds and seabirds. In adjacent estuaries, the intertidal flats and littoral zones of shallow embayments are heavily used by shorebirds, raptors, and colonial waterbirds in the May to September periods, with use by duck and geese heaviest from October to March. With the regional degradation of estuarine habitats and population declines of many species of waterbirds in the past 20 yr, some management recommedations relevant to shallow waters include: better protection, enhancement, and creation of small bay islands (small and isolated to preclude most mammalian predators) for nesting and brooding birds, especially colonial species; establishment of sanctuaries from human disturbance (e.g., boating, hunting) both in open water (waterfowl) and on land; better allocation of sandy dredged materials to augment islands or stabilize eroding islands; improvement in water management of existing impoundments to ensure good feeding, resting, and nesting opportunities for all the waterbirds; support for policies to preclude point and nonpoint source runoff of chemicals and nutrients to enable submerged aquatic vegetation to recover in many coastal bays; and improvement in environmental education concerning disturbance to wildlife for boaters and recreationists using the coastal zone. *** DIRECT SUPPORT *** A01BY074 00007  相似文献   

Anelastic parameters of the mantle and Love numbers consistent with modern VLBI data     

E. Groten  S. M. Molodensky 《Journal of Geodesy》1996,70(10):622-632

Summary The domain of the possible values of the mantle's anelasticity parameters and Love numbers based on modern VLBI-data is found. A new method of the joint analysis of VLBI- and tidal data is suggested, which gives possibility to obtain better estimations of the Q-factor of the free core nutation.  相似文献   

Heavy metals in stream sediments: Effects of human activities     

Erwin J. Mantei  Melvin V. Foster 《Environmental Geology》1991,18(2):95-104

The content of 11 heavy metals in the sediments of a stream system was determined by atomic absorption analysis. Geochemical phases were investigated using a sequential extraction scheme, and bulk contents were assessed with a single HNO₃ extraction. Certain heavy metals were associated with different geochemical phases. Co, Mn, and Ba concentrated primarily in the carbonate and Mn phases, while all the remaining metals concentrated in the Fe and remnant phases. Features located along the stream system influenced the content of heavy metals. Results from the geochemical phases indicated Cu, Pb, Zn, Cd and Ag were emitted by one landfill, while Cd, Ba, and Ag were emitted by a second landfill. A wastewater treatment facility appeared to emit Ni and Cu. A stream draining a reservoir and joining the study stream resulted in dilution of the heavy metals in the sediments. A populated area along the study stream appeared to emit Mn. The single HNO₃ extraction procedure is quicker to perform than the sequential extraction but does not indicate the phase associations.  相似文献   

The deviations of the sea surface from the geoid and their effect on geoid computation     

Jürgen Brennecke  Erwin Groten 《Journal of Geodesy》1977,51(1):47-51

The effects of the deviations of sea surface topography from the geoid are estimated for terrestrial geoid computations as obtained from Stokes' formula. The results are based on an equal-area expansion of Lisitzin's sea surface topography data in a spherical harmonic series. It is realized that those data affect mainly the harmonics of degree n≤10. Consequently, in geoids obtained from combination solutions (where low harmonics are dominated by harmonics as obtained from differential orbit improvement) the sea surface topography effects are relatively small.  相似文献   

Nachweis und Bestimmung geringster Nikotinkonzentrationen in Wasserproben     

H. R. Hegi  Erika Fischer  Erwin Märki 《Aquatic Sciences - Research Across Boundaries》1964,26(1):91-101

  相似文献