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341.
Žukovič Milan Borovský Michal Lach Matúš Hristopulos Dionissios T. 《Mathematical Geosciences》2020,52(1):123-143
Mathematical Geosciences - A novel Gibbs Markov random field for spatial data on Cartesian grids based on the modified planar rotator (MPR) model of statistical physics has been recently introduced... 相似文献
342.
A. Richter M. Eisinger A. Ladstätter-weißenmayer J.P. Burrows 《Journal of Atmospheric Chemistry》1999,32(1):83-99
Zenith sky observations of BrO over Bremen (53°N) are reported for the period of September 1994 to January 1996. BrO differential slant columns between 90° and 80° solar zenith angle showed a strong seasonal variation between a winter maximum of 1.9·1014 molec/cm2 and a summer minimum of 0.6·1014 molec/cm2. The seasonal variation in BrO twilight values is shown to be inversely correlated with NO2 columns in agreement with current knowledge of gas phase chemistry of bromine. In contrast to model predictions, no significant difference between morning and evening BrO measurements was observed. During a 6 day polar vortex excursion to mid-latitudes OClO could be measured above Bremen indicating chlorine activation in the vortex air. No significant increase in BrO differential slant columns was detected during this time. 相似文献
343.
H. K. Roscoe P. V. Johnston M. Van Roozendael A. Richter A. Sarkissian J. Roscoe K. E. Preston J-C. Lambert C. Hermans W. DeCuyper S. Dzienus T. Winterrath J. Burrows F. Goutail J-P. Pommereau E. D'Almeida J. Hottier C. Coureul R. Didier I. Pundt L. M. Bartlett C. T. McElroy J. E. Kerr A. Elokhov G. Giovanelli F. Ravegnani M. Premuda I. Kostadinov F. Erle T. Wagner K. Pfeilsticker M. Kenntner L. C. Marquard M. Gil O. Puentedura M. Yela D. W. Arlander B. A. Kastad Hoiskar C. W. Tellefsen K. Karlsen Tornkvist B. Heese R. L. Jones S. R. Aliwell R. A. Freshwater 《Journal of Atmospheric Chemistry》1999,32(2):281-314
In June 1996, 16 UV-visible sensors from 11 institutes measured spectra of the zenith sky for more than 10 days. Spectra were analysed in real-time to determine slant column amounts of O3 and NO2. Spectra of Hg lamps and lasers were measured, and the amount of NO2 in a cell was determined by each spectrometer. Some spectra were re-analysed after obvious errors were found. Slant columns were compared in two ways: by examining regression analyses against comparison instruments over the whole range of solar zenith angles; and by taking fractional differences from a comparison instrument at solar zenith angles between 85° and 91°. Regression identified which pairs of instruments were most consistent, and so which could be used as universal comparison instruments. For O3, regression slopes for the whole campaign agreed within 5% for most instruments despite the use of different cross-sections and wavelength intervals, whereas similar agreement was only achieved for NO2 when the same cross-sections and wavelength intervals were used and only one half-day's data was analysed. Mean fractional differences in NO2 from a comparison instrument fall within ±7% (1-sigma) for most instruments, with standard deviations of the mean differences averaging 4.5%. Mean differences in O3 fall within ±2.5% (1- sigma) for most instruments, with standard deviations of the mean differences averaging 2%. Measurements of NO2 in the cell had similar agreement to measurements of NO2 in the atmosphere, but for some instruments measurements with cell and atmosphere relative to a comparison instrument disagreed by more than the error bars. 相似文献
344.
G. M. Richter 《Astronomische Nachrichten》1980,301(4):157-163
Wenn drei Platten des gleichen Feldes für die Abtastung mit einem Mikrophotometer zur Verfügung stehen und Sternkataloge aus den Abtastungen zusammengestellt werden, dann lassen sich Vollständigkeit und Zuverlässigkeit dieser Kataloge und die wahren Sternzahlen als Funktionen de Helligkeit oder anderer Parameter ableiten bis zur Plattengrenze. Ein Anwendungsfall wird beschrieben. 相似文献
345.
Mathias Mueller Onyedika A. Igbokwe Benjamin Walter Chelsea L. Pederson Sylvia Riechelmann Detlev K. Richter Richard Albert Axel Gerdes Dieter Buhl Rolf D. Neuser Giovanni Bertotti Adrian Immenhauser 《Sedimentology》2020,67(2):849-881
Early marine diagenetic dolomite is a rather thermodynamically-stable carbonate phase and has potential to act as an archive of marine porewater properties. However, the variety of early to late diagenetic dolomite phases that can coexist within a single sample can result in extensive complexity. Here, the archive potential of early marine dolomites exposed to extreme post-depositional processes is tested using various types of analyses, including: petrography, fluid inclusion data, stable δ13C and δ18O isotopes, 87Sr/86Sr ratios, and U-Pb age dating of various dolomite phases. In this example, a Triassic carbonate platform was dissected and overprinted (diagenetic temperatures of 50 to 430°C) in a strike-slip zone in Southern Spain. Eight episodes of dolomitization, a dolostone cataclasite and late stage meteoric/vadose cementation were recognized. The following processes were found to be diagenetically relevant: (i) protolith deposition and fabric-preservation, and marine dolomitization of precursor aragonite and calcite during the Middle–Late Triassic; (ii) intermediate burial and formation of zebra saddle dolomite and precipitation of various dolomite cements in a Proto-Atlantic opening stress regime (T ca 250°C) during the Early–Middle Jurassic; (iii) dolomite cement precipitation during early Alpine tectonism, rapid burial to ca 15 km, and high-grade anchizone overprint during Alpine tectonic evolution in the Early Eocene to Early Miocene; (iv) brecciation of dolostones to cataclasite during the onset of the Carboneras Fault Zone activity during the Middle Miocene; and (v) late-stage regression and subsequent meteoric overprint. Data shown here document that, under favourable conditions, early diagenetic marine dolomites and their archive data may resist petrographic and geochemical resetting over time intervals of 108 or more years. Evidence for this preservation includes preserved Late Triassic seawater δ13CDIC values and primary fluid inclusion data. Data also indicate that oversimplified statements based on bulk data from other petrographically-complex dolomite archives must be considered with caution. 相似文献
346.
The results of galaxy counts on plates taken with the Tautenburg Schmidt telescope in a 36□° region around the globular cluster M3 are presented and discussed. More than 26000 galaxies on four blue plates (covering the whole region) and nearly 18000 galaxies on two red plates (covering half the region) have been counted in 5′ × 5′ cells. The discussion in the present paper includes a first determination of the two-point correlation function and a dispersion curve analysis. The results are not very different from those obtained for the Jagiellonian field. It is suggested that counting errors may influence the conclusions drawn for the space distribution of galaxies and its possible secular change. 相似文献
347.
On Tautenburg Schmidt plates in system V taken at seeings of about 2″ the determination of real angular diameters of compact galaxies down to 4″ is possible. Diameter-magnitude diagrams of objects in four fields around the globular cluster M3 show the possibility for getting homogeneous material concerning both the uniformity of the equidensitometric copying process and the measuring process with the iris photometer in order to determine the integral brightness of single galaxies from their limiting equidensities. 相似文献
348.
G. A. Richter 《Astronomische Nachrichten》1989,310(2):143-144
Observations on 4180 sky patrol plates of Sonneberg Observatory showed that this star belongs to the SS Cygni subclass of cataclysmic variables with cycle length between about 30 and 48 days. Possible orbital periods are discussed. 相似文献
349.
350.
36 objects with mainly negative (U—B) indices were investigated for variability and proper motions. 10 objects with significant or suspected proper motions and 8 variable objects were detected. Using these criteria, it was possible to separate white dwarfs from quasi-stellar objects to some extent. 相似文献