A concept for global access to information on geographical databases

Monitoring of the ecological as well as economical aspects of the planet Earth will in future require more sophisticated data obtaining systems (e. g. satellites) and data processing devices (e. g. GIS). In order to process the great amount of data, detailed information on geographical databases has to be provided in an easy way. In this paper a concept of an information system on geographical databases is presented which encompasses a centrally managed international directory with summary information as well as local information interfaces geographical databases. An information interface provides detailed information on the extent, structure and geographical meaning of the data stored in the geographical database belonging to it. To describe this information a conceptual scheme, based on an object oriented approach, is developed.     

Local advection processes in the surface layer of the marginal ice zone

Micro-scale turbulent transport processes over the marginal ice zone have been studied by use of a two-dimensional numerical model. It has been found that internal boundary layers (IBLs) of horizontal mean velocity, temperature, and specific humidity reveal a near field and a far field. In the near field, the change in surface roughness dominates the height and growth rate of a velocity IBL. The change in surface heat flux governs the near field of a temperature and humidity IBL. In the far field, approximately x/¦L _*2 ¦ ~ 20, where L _*2 is the downstream Obukhov length, the downstream stratification more and more influences the growth rate of IBLs basically by modifying the eddy viscosity.Above more complex terrain consisting of an ensemble of ice strips and leads, a merging height h ^M develops, below which the horizontal variability of the surface modification is clearly observed; h ^M varies with the length scale L of surface modification approximately in proportion to h ^M /L ~ 1/20 – 1/10, as a rule of thumb. Above the merging height, an enveloping IBL exists, whose growth depends on the ice cover, i.e., on the integral of surface modification, but changes very little with L.Local advection of momentum, heat, and moisture clearly affects the local surface heat fluxes. Sensible and latent heat fluxes are found to show also a near and far field. However, if areally averaged surface fluxes are to be deduced from grid-averaged flow variables, then details of local advection can be neglected to a reasonably good approximation.     

Estimation of the Monin-Obukhov similarity functions from a spectral model

From measured one-dimensional spectra of velocity and temperature variance, the universal functions of the Monin-Obukhov similarity theory are calculated for the range –2 z/L + 2. The calculations show good agreement with observations with the exception of a range –1 z/L 0 in which the function _m , i.e., the nondimensional mean shear, is overestimated. This overestimation is shown to be caused by neglecting the spectral divergence of a vertical transport of turbulent kinetic energy. The integral of the spectral divergence over the entire wave number space is suggested to be negligibly small in comparison with production and dissipation of turbulent kinetic energy.Notation a,b,c contants (see Equations (–4)) - C_i constants i=u, v, w, (see Equation (5) - k_me,k_mT peak wave numbers of 3-d moel spectra of turbulent kinetic energy and of temperature variance, respectively - k_mi peak wave numbers of 1-d spectra of velocity components i=u, v, w and of temperature fluctuations i= - k_sb, k_c characteristics wave numbers of energy-feeding by mechanical effects being modified by mean buoyancy, and of convective energy feeding, respectively - L Monin-Obukhov length - % MathType!MTEF!2!1!+-% feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqefm0B1jxALjhiov2D% aebbfv3ySLgzGueE0jxyaibaiiYdd9qrFfea0dXdf9vqai-hEir8Ve% ea0de9qq-hbrpepeea0db9q8as0-LqLs-Jirpepeea0-as0Fb9pgea% 0lrP0xe9Fve9Fve9qapdbaqaaeGacaGaaiaabeqaamaabaabcaGcba% Gabeivayaaraaaaa!3C5B!\[{\rm{\bar T}}\] difference of mean temperature and mean potential temperature - T* Monin-Obukhov temperature scale - velocity of mean flow in positive x-direction - u* friction velocity - u, v, w components of velocity fluctuations - z height above ground - von Kármanán constant - temperature fluctuation - _m nondimensional mean shear - _H nondimensional mean temperature gradient - nondimensional rate of lolecular dissipation of turbulent kinetic energy - _D nondimensional divergence of vertical transports of turbulent linetic energy     

Parametric cubic splines and geologic shape descriptions

Parametric cubic splines provide a versatile means of describing and sampling shapes and curves commonly found in geology. These splines allow the researcher to treat easily curves which are not single-valued in Cartesian or polar coordinates. In addition, they simultaneously provide approximations to positions, slopes, and curvatures of the curve being considered. In conjunction with simple digitizing equipment and a small computer, the method of parametric cubic spline approximation allows the researcher to analyze curves or outlines in cases where the more rapid technique involving video imaging equipment is either not applicable or not available.     

The microstructure of minerals in coarse-grained Ca-Al-rich inclusions from the Allende meteorite

The microstructure and microchemistry of minerals in Ca-Al-rich, coarse-grained inclusions (CAI) from the Allende meteorite have been investigated with transmission electron microscopy (TEM). Spinels contain only low to moderate dislocation densities and are characterized by a ubiquitous, fine black spotty texture believed to originate from a slightly non-stoichiometric composition. Ti-Al-pyroxenes are relatively featureless, but contain veins of secondary phases apparently deposited in unhealed cracks. Chromite has been identified in the veins, suggesting transport of oxidized iron during alteration. Melilites exhibit the greatest variety of microstructures and are the most heavily altered phase in CAI. High dislocation densities are common and crystals exhibit considerable internal strain, indicating that they have not been annealed. Alteration occurs both as veins along cracks and in fronts extending across several grains. Plagioclase is commonly twinned, but dislocations are rare. The size and morphology of antiphase domains suggest a high temperature of formation with significant low-temperature annealing. Submicron pyroxene precipitates are a ubiquitous and unusual feature of Allende plagioclase whose properties are most consistent with prolonged slow cooling and equilibration after plagioclase crystallization. The precipitates appear to be sufficiently abundant to contain the majority of Mg present in plagioclase but do not easily account for Na and Ti abundances. Wollastonite needles from a cavity in a “fluffy” Type A inclusion exhibit the growth habits and relatively perfect external surfaces indicative of direct condensation from a vapor. Alteration products are predominantly crystalline and alteration of melilite appears to have proceeded primarily by solid-state diffusion at a temperature of approximately 920°K. Overall, the TEM observations suggest that CAI formed under near equilibrium conditions characterized by slow cooling and that solid-state bulk diffusion was the major process affecting their post-crystallization history.     

Gravity change and land uplift in Fennoscandia 1966–1984

An analysis is made of the results from all repeated gravity measurements of the Fennoscandian land uplift gravity line 63°. The line is, thereby, divided into two separate parts: one part west of the land uplift maximum, and the other part east of the land uplift maximum. A statistically significant change of gravity is found both for the western part and the eastern one. Both parts give a relation between gravity change and land uplift of about ?0.22μgal/mm.