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This paper advocates the use of GIS for the evaluation of the vulnerability of coastal waters and presents a method for mapping their vulnerability to algal blooms. The method incorporates probability mapping of parameters used to describe coastal waters and fuzzy sets. To allow the modelling of processes where some components cannot substitute for other components the 'no trade off' convex combination formula is proposed. The maps of vulnerability for the Gulf of Gdansk, which were created using this method, may be used to find out which rivers and water discharges play a dominant role in eutrophication.  相似文献   
163.
The LOw-Frequency ARray (LOFAR) is a new radio interferometer that consists of an array of stations. Each of them is a phase array of dipole antennas. LOFAR stations are distributed mostly in the Netherlands, but also throughout Europe. In the article we discuss the possibility of using this instrument for solar and space weather studies, as well as ionosphere investigations. We are expecting that in the near future the LOFAR telescope will bring some interesting observations and discoveries in these fields. It will also help to observe solar active events that have a direct influence on the near-Earth space weather.  相似文献   
164.
In the paper a modification of the polynomial extrapolation for solving the problem of motion nearby the equilibrium points is presented. It appears that the modification yields a better approximation of the exact solution than the convential polynomial extrapolation and other methods. Moreover, the modification conserves the Jacobi constant of motion. Computer examples for orbits nearby the equilibrium points of the Sun-Jupiter system are given.  相似文献   
165.
Among the observed circumstellar dust envelopes a certain population, planetary debris disks, is ascribed to systems with optically thin dust disks and low gas content. These systems contain planetesimals and possibly planets and are believed to be systems that are most similar to our solar system in an early evolutionary stage. Planetary debris disks have been identified in large numbers by a brightness excess in the near-infrared, mid-infrared and/or submillimetre range of their stellar spectral energy distributions. In some cases, spatially resolved observations are possible and reveal complex spatial structures. Acting forces and physical processes are similar to those in the solar system dust cloud, but the observational approach is obviously quite different: overall spatial distributions for systems of different ages for the planetary debris disks, as opposed to detailed local information in the case of the solar system. Comparison with the processes of dust formation and evolution observed in the solar system therefore helps understand the planetary debris disks. In this paper, we review our present knowledge of observations, acting forces, and major physical interactions of the dust in the solar system and in similar extra-solar planetary systems.  相似文献   
166.
We consider the motion of a spacecraft which consists of a rigid body with a thin viscoelastic circular ring attached at some point of the body. Assuming that the stiffness of the ring is large and the dissipation is small enough, we study the quasi-static motion which is set in after free elastic oscillations have damped. In particular, the steady-state motions in the weakly elliptic orbit are found and their stability is investigated.  相似文献   
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This paper presents application of the EULAG model combined with a sophisticated double-moment warm-rain microphysics scheme to the model intercomparison case based on RICO (Rain in Cumulus over Ocean) field observations. As the simulations progress, the cloud field gradually deepens and a relatively sharp temperature and moisture inversions develop in the lower troposphere. Two contrasting aerosol environments are considered, referred to as pristine and polluted, together with two contrasting subgridscale mixing scenarios, the homogeneous and the extremely inhomogeneous mixing. Pristine and polluted environments feature mean cloud droplet concentrations around 40 and 150 mg?1, respectively, and large differences in the rain characteristics. Various measures are used to contrast evolution of macroscopic cloud field characteristics, such as the mean cloud fraction, the mean cloud width, or the height of the center of mass of the cloud field, among others. Macroscopic characteristics appear similar regardless of the aerosol characteristics or the homogeneity of the subgrid-scale mixing.  相似文献   
170.
In this work, the GOCE satellite orbit is described in the aspect of perturbations in the Keplerian osculating elements. The perturbations come from the Earth and ocean tides, the gravitation of the Moon, the gravitation of the Sun, the gravitation of planets and Pluto, and the relativity effects. These perturbations are computed for the 30-day interval with a sampling of 2 min. To obtain the simulated orbit, the Cowell numerical integration method of 8th order is used. The first part of the work contains the root mean square (RMS) values of aforementioned perturbations due to the specified forces. The perturbations were compared taking into account their RMS characteristics.  相似文献   
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