Thermodynamic non-equilibrium theory of the condensational growth of atmospheric water drops     

U. Wacker  F. Herbert 《Meteorology and Atmospheric Physics》1998,66(3-4):173-195

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Parameterization of the CCN-humidity spectrum in dependency on nucleation conditions and aerosol size distribution     

F. Herbert  Dr. U. Wacker 《Meteorology and Atmospheric Physics》1998,68(3-4):213-220

Summary Atmospheric CCN-humidity spectra (describing the CCN-number concentration as function of supersaturation) are derived as the integral over given particle size distributions. In that concept the finite boundary, representing the limiting activated particle size, results from the critical values of the Köhler-curve. As utilization of this general outcome different representative aerosol size distributions of the power law type as well as the log-normal type are chosen for case studies which are compared to empirical results. The dependency on temperature of the limiting activated particle size is shown to provide a non-negligible influence on the number of activated particles.With 3 Figures  相似文献   

Corundum-bearing residues produced through the evaporation of natural and synthetic hibonite     

CHRISTINE FLOSS  AHMED EL GORESY  ERNST ZINNER  HERBERT PALME  GERD WECKWERTH  WERNER RAMMENSEE 《Meteoritics & planetary science》1998,33(2):191-206

Abstract— We have produced corundum-bearing residues through the evaporation of natural and synthetic hibonite samples. The sequence of major element losses as well as volatility related trace element fractionations in these residues are similar to those previously observed in residues from the evaporation of chondritic starting material, which suggests that the processes by which these fractionations occur may be largely independent of the starting material used. However, the mineralogy of the residues does depend on the composition of the starting material and, to some extent, on the conditions under which evaporation took place. Similarly, the degree of isotopic mass fractionation observed in the residues is composition-dependent. This observation means that it may be possible to use isotopic data for several elements to constrain the compositions of precursor materials of Ca-Al-rich inclusions, which have an evaporation origin. Although corundum-bearing inclusions are known, their origins are complex and variable, and the scarcity of such inclusions indicates that melting of hibonite, with or without concomitant evaporation, must have been a rare process in the solar nebula. By evaporating mixtures of synthetic oxides of the rare earth elements, we have reproduced the patterns of Group III inclusions and some of the characteristics of ultrarefractory patterns. However, the extreme conditions required to do so indicate that refractory inclusions with these patterns probably have a condensation rather than evaporation origin.  相似文献   

Note in reply to Egger and Schär's comment on our article “A solenoid-mass continuity invariance criterion related to the potential vorticity conservation”     

Prog F. Herbert  Prog H. Pichler 《Meteorology and Atmospheric Physics》1996,59(3-4):259-261

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Precise kinematic GPS positioning     

Herbert Landau 《Journal of Geodesy》1989,63(1):85-96

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Mathematical studies on the aerosol concentration in drops changing due to particle scavenging and redistribution by coagulation     

Dr K. D. Beheng  Prof F. Herbert 《Meteorology and Atmospheric Physics》1986,35(4):212-219

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Petrogenesis of a tholeiite-boninite sequence from Ayios Mamas,Troodos ophiolite: evidence for splitting of a volcanic arc?     

Martin F. J. Flower  Herbert M. Levine 《Contributions to Mineralogy and Petrology》1987,97(4):509-524

Lavas and intrusives from Ayios Mamas, at the western end of the Limassol Forest Complex, south of the Arakapas Fault Belt, Troodos, comprise three groups: (A) a basal sequence of pillow lavas (intruded by dikes and sills) with the phenocryst assemblage PLAG+CPX+MT±OL; (B) a middle sequence of pillows and massive flows [CPX+PLAG±OL]; and (C) an upper sequence mostly of pillows and breccia [OL+OPX+CPX+SP]. The lower group is tholeiitic, and the upper two groups boninitic. Group C whole-rock and glass Mg-numbers exceed 72 and range up to 78, with corresponding olivine compositions of Fo₉₂. They are strongly depleted in high-field strength elements, and on the basis of Cr-Y variation and major element mass balances, are interpreted to reflect partial melting of a basalt-depleted (CPX-) harzburgite source. Group A tholeiites, in contrast, are interpreted to derive from a more fertile lherzolite source. Magmaphile and compatible trace element variation is best modelled after an open magma system, involving periodic replenishment, tapping, and fractionation, although neither tholeiites nor boninites represent steady-state compositions. The boninites belong to a CaO-rich, SiO₂-poor variant, resembling those from Guam, but contrasting with those from Bonin and Cape Vogel. MORB-normalized enrichment of low-field strength elements K, Sr, Ba, and Rb in all groups indicates subduction-derived source contamination. It is proposed that the Ayios Mamas section reflects splitting of a volcanic arc, prior to back-arc spreading in an environment analogous to that of the present-day Andaman Sea.  相似文献   

Meteorology and haze structure during AGASP-II,Part 2: Canadian Arctic flights, 13–16 April 1986     

H. A. Bridgman  R. C. Schnell  G. A. Herbert  B. A. Bodhaine  S. J. Oltmans 《Journal of Atmospheric Chemistry》1989,9(1-3):49-70

In April 1986, a well-instrumented NOAA WP-3D research aircraft conducted three flights in the Canadian Arctic tied to the Canadian Atmospheric Environment Service baseline station in Alert, Northwest Territories. Two of the flights were coordinated with the National Aeronautical Establishment of Canada Twin Otter and the University of Washington C-131 research aircraft. The haze observed in the Canadian Arctic was well-aged and mixed throughout the troposphere in concentrations well below those observed during the previous weeks in the Alaskan Arctic. Over the ice, beneath the surface temperature inversion, ozone was generally depleted to near zero. Over the coast at Alert, there is evidence that topography and downslope winds reduce the strength of the inversion, thus allowing lower tropospheric gases and aerosols to mix down to the surface. At the top of the troposphere, an aerosol-depleted region was observed. In the lower stratosphere, aerosol concentrations were elevated above those observed in the troposphere.  相似文献   

Cooling and contamination of mafic and ultramafic magmas during ascent through continental crust   总被引：1，自引：0，他引：1  

Herbert E. Huppert  R. Stephen  J. Sparks 《Earth and Planetary Science Letters》1985,74(4):371-386

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Zur Ökologie des Brachsen (Abramis brama (L.)) im Bodensee     

Dr. Herbert Von Löffler 《Aquatic Sciences - Research Across Boundaries》1984,46(1):147-162

The reactions of the bream,Abramis brama, to the ecological changes due to man-made eutrophication of Lake Constance were investigated. It could be demonstrated that the bream adapted only to a negligible amount. Likely due to its largeness, structure of the body and population composition the bream is more conservative than perch, roach and whitefish. The only reactions to the changed environment are modificated vertical and horizontal distribution and partly plancton feeding in summer.   相似文献