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排序方式: 共有930条查询结果,搜索用时 46 毫秒
91.
Christian Pfister Rudolf Brázdil Rüdiger Glaser Anita Bokwa Franz Holawe Danuta Limanowka Oldřich Kotyza Jan Munzar Lajos Rácz Elisabeth Strömmer Gabriela Schwarz-Zanetti 《Climatic change》1999,43(1):111-150
Thirty-two weather diaries written in astronomical calendars in central Europe in the late fifteenth and sixteenth centuries are presented and discussed. Systematic weather observations were promoted by the rise of planetary astronomy and its application in astro-meteorology. The practice of keeping weather diaries spread from Cracow (Poland) to Ingolstadt (Germany) and from there to other universities. The data obtained from these sources provided the backbone for setting up series of precipitation indices for Poland, Germany and Switzerland. Monthly statistics of days with precipitation, snowfall and frost were computed by counting the relevant entries in the most important diaries. The results were compared with either those obtained from instrumental measurements in the same place or with those from modern instrumental measurements in a neighbouring place. The final results show that autumn was considerably colder in the early sixteenth century. April was considerably drier and July was wetter during the period 1508-1531 than during 1901-1960. In order to highlight the impact of weather patterns on grain prices in a year of crisis, the timing of wet and dry spells in southern Poland and southern Germany is compared for the year 1529. Winters became 1.7°C colder from 1564 to 1576 and the month of July tended to be wetter than in 1901-1960. Details noted in the diaries kept between 1585 and 1600 by the astronomers Brahe (near Copenhagen) and Fabricius (in the Ostfriesland region of northwestern Germany) closely agree. It rained more often in June and July and temperatures dropped. The winter months were more frequently dominated by winds from easterly directions, the frequency of snowfall was higher and a deficit occurred in precipitation. This points to a higher frequency of high pressure in the Fennoscandian area with cold air advection from the east or northeast. 相似文献
92.
The distribution of controlling pressure formations, occurring in the Northern Hemisphere during the winters (January and February) of the years 1952 – 1996, has been analysed. It was found that the deepening of the Icelandic and Aleutian pressure lows is connected not only with a particular QBO phase and level of geomagnetic activity (Bochníek et al., 1999) but also with a particular level of solar activity. 相似文献
93.
The solar eclipse on August 11, 1999, observed in the region covered by many geomagnetic observatories, has offered a unique opportunity to look for an effect of the eclipse on geomagnetic pulsations. The pulsation activity digital data have been taken from Budkov Observatory in the Czech Republic (in the X component only), from observatories in Germany (Niemegk, Fürstenfeldbruck, Bad Bergzabern), in Hungary (Nagycenk), and for comparison in South Africa (Hermanus, conjugate-point station), and in Finland (Sodankylä, far from the eclipse zone). At all these stations the field in all three component has been recorded. The pulsation amplitudes in the X component exhibit a long-term minimum near the time of the eclipse. Spectral analysis of selected short intervals confirmed this decrease and also revealed a decrease of the average pulsation period during the eclipse. Such a change in the amplitude or in the period was not observed outside of the eclipse interval or in other days. Investigation in some narrower frequency bands showed that the maximal decrease occurred in the 15–20 s band. All these changes can be found in records from all the stations near the eclipse totality belt, also in records at the conjugate-point station, where no eclipse occurred. No signature has been found in records at the station situated far from the eclipse zone. 相似文献
94.
J. Klokočník Ch. Reigber P. Schwintzer C. A. Wagner J. Kostelecký 《Journal of Geodesy》2002,76(4):189-198
The new GFZ/GRGS gravity field models GRIM5-S1 and GRIM5-C1, currently used as initial models for the CHAMP mission, have
been compared with other recent models (JGM 3, EGM 96) for radial orbit accuracy (by means of latitude lumped coefficients)
in computations on altimetry satellite orbits. The bases for accuracy judgements are multi-year averages of crossover sea
height differences from Geosat and ERS 1/2 missions. This radially sensitive data is fully independent of the data used to
develop these gravity models. There is good agreement between the observed differences in all of the world's oceans and projections
of the same errors from the scaled covariance matrix of their harmonic geopotential coefficients. It was found that the tentative
scale factor of five for the formal standard deviations of the harmonic coefficients of the new GRIM fields is justified,
i.e. the accuracy estimates, provided together with the GRIM geopotential coefficients, are realistic.
Received: 20 February 2001 / Accepted: 24 October 2001 相似文献
95.
P. Kolář 《Journal of Seismology》2000,4(2):197-213
Two seismic source studies usingteleseismic data are performed by Simulated Annealing(SA), a non-linear inversion method. The Very FastSimulated Annealing (VFSA) algorithm is used and onlyteleseismic data are inverted. We have designed a fastand efficient way of multiple direct problemevaluation, which is based on pre-calculating theelementary Green's function. During the process we setthe values of the inversion control parameters(temperature, number of iterations) and modified thecooling schedule. In the current version, theinversion seeks for the point source mechanism, thedepth of the source, the scalar moment and the sourcetime function (STF). The method is applied to twoearthquakes: 18 Nov. 1992 in Greece, M 5.9 and 14 Sep.1995 in Mexico, M7.3. The calculation is performed ona simple 1D model of the structure. For the firstearthquake the inversion recovered the solution fairlywell; for the second the solution was less acceptable.However, we do not consider this fact to be a failureof the method, but a consequence of an inadequatemodel of the source and of the medium structure. Acasual attempt of reliability determination was alsoperformed; the obtained values of errors arereasonable, except for a few cases when the methodfailed. 相似文献
96.
Summary The disturbing gravitational effect of the irregularities of the shape of the coremantle boundary are studied at a point on the Earth's surface. The effect is computed for models of local and zonal distribution of the disturbing masses under the assumption that the total mass of the Earth remains constant. Formulae giving the disturbing gravitational effect as a function of the distribution of the disturbing masses and of the position of the point of observation on the Earth's surface are derived for the individual models. Numerical values of the disturbances have been calculate in all cases. 相似文献
97.
Summary The morphology of the Wadati-Benioff zone in the Kermadec region, based on the distribution of 1100 earthquake foci, verified the existence of an intermediate aseismic gap and its relation to active andesitic volcanism, and the non-uniformity of subduction due to the hampering effect of the main structural features of the subducting Pacific plate. Two cycles of the recently active subduction in the Tonga-Kermadec island arc were found. 相似文献
98.
Deformation properties of the lithosphere derived from data on recent crustal movements of the earth
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99.
aam u m¶rt; ¶rt;uau m aum n - u -nuau ¶rt; ¶rt;¶rt; ¶rt;a. ¶rt;am umuu u, m m uam nuuu m¶rt;a am Va nuumuu n¶rt;am auauu muuu n¶rt;umu.
Dedicated to RNDr. Jan Pícha, CSc., on his 60th Birthday 相似文献
Dedicated to RNDr. Jan Pícha, CSc., on his 60th Birthday 相似文献
100.
Elastic properties of eclogite rocks from the Bohemian massif 总被引:1,自引:0,他引:1
Vladislav Babuška Jiří Fiala D. J. Mayson R. C. Liebermann Reviewer J. Buben 《Studia Geophysica et Geodaetica》1978,22(4):348-361
Summary Compressional velocity anistropy has been studied in detail at atmospheric pressure for 78 specimens of 23 types of eclogite rocks from the Bohemian massif. For nine of these rock types, compressional and shear velocities were measured as a function of pressure to750 MPa at room temperature. The velocity anisotropy for both compressional and shear waves is less than4% at high pressure. The velocities increase with increasing garnet content and decrease with increasing symplectitization. The Moldanubian eclogites have significantly higher velocities, on the average, than the eclogites from the Kruné hory crystalline complex, although the densities of both groups are comparable. 相似文献