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1.
Summary ?High-frequency temperature variability was investigated in the temperature time series measured at Prague-Sporilov (Czech
Republic) between 1994–2001. The calculations were performed for time series of surface air temperature averaged for 6-hour
intervals. Variability was detected by the method of absolute difference of temperature anomalies between two adjacent discrete
time periods. The results indicated a frequency dependence of variability. For 24-hour intervals the variability exhibits
an irregular character and decreases with time in the eight-year observation period. Variability time series calculated for
the 6-hour intervals did not reveal any significant trend, however, apparent quasi-seasonal oscillations exist. A significant
correlation between the North Atlantic Oscillation (NAO) activity and temperature variability can be observed. Higher NAO-index
values at all frequencies tend to be associated with higher variability.
Received February 28, 2002; revised March 25, 2002; accepted July 18, 2002 相似文献
2.
L. Bodri 《Theoretical and Applied Climatology》1994,49(1):53-57
Summary Rescaled range analysis of the annual mean surface air temperatures at 7 meteorological stations in Hungary for the period of 1901–1991 indicates that the considered temperatures are fractals with a mean fractal dimension of 1.23 ± 0.01. This value compares favourably with the fractal dimensions of other climatic records, both on small time scale of 10–100 years and for time spans 103–106 years. Possibly such fractal dimensions are characteristic of climate change over the whole spectral range of 10 to 106 years. If this assumption becomes confirmed through analysis of a wider set of climatic records, long-range climatic prediction (in statistical sense) on different time scales will appear feasible.With 4 Figures 相似文献
3.
Accurate temperature–depth profiles may help to assess the temperature variations associated with the climate changes in the past. Ninety-eight ground surface temperature histories inverted from the temperature–depth borehole logs drilled on the territory of the Czech Republic [Bodri, L.,
ermák, V., 1995. Climate changes of the last millennium inferred from borehole temperatures: results from the Czech Republic — Part I. Global Planet. Change 11, pp. 111–125; Bodri, L.,
ermák, V., 1997. Climate changes of the last two millennia inferred from borehole temperatures: results from the Czech Republic — Part II. Global Planet. Change 14, pp. 163–173.] are used to reconstruct the regional patterns of the respective climate change. The climate was mapped for the following periods: 1100–1300 A.D. (Little Climatic Optimum), 1400–1500 A.D., 1600–1700 A.D. (main phase of the Little Ice Age), and for the most recent climate trend after year 1960. Comparison of the obtained maps with the meteorological observations and proxy climatic reconstructions confirmed good applicability of the “geothermal” paleoclimatic reconstructions for the regional studies. 相似文献
4.
V. Čermák J. Šafanda L. Bodri M. Yamano E. Gordeev 《Studia Geophysica et Geodaetica》2006,50(4):675-695
To reconstruct the recent climate history in Kamchatka, a series of repeated precise temperature logs were performed in a
number of boreholes located in a broad east-west strip (between 52 and 54°N) in the central part of Kamchatka west of Petropavlovsk-Kamchatski.
Within three years more than 30 temperature logs were performed in 10 holes (one up to six logs per hole) to the depth of
up to 400 metres. Measured temperature gradients varied in a broad interval 0 to 60 mK/m and in some holes a sizeable variation
in the subsurface temperatures due to advective heat transport by underground water was observed. Measured data were compared
with older temperature profiles obtained in the early eighties by Sugrobov and Yanovsky (1993). Even when older data are of
poorer precision (accuracy of about 0.1 K), they presented valuable information of the subsurface temperature conditions existing
20–25 years ago. Borehole observations and the inverted ground surface temperature histories (GSTHs) used for the paleoclimate
reconstruction were complemented with a detailed survey of meteorological data. Namely, the long-term surface air temperature
(SAT) and precipitation records from Petropavlovsk station (in operation since 1890) were used together with similar data
from a number of local subsidiary meteo-stations operating in Central Kamchatka since 1950. Regardless of extreme complexity
of the local meteorological/climate conditions, diversity of borehole sites and calibration of measuring devices used during
the whole campaign, the results of the climate reconstruction supported a general warming of about 1 K characteristic for
the 20th century, which followed an inexpressive cooler period typical for the most of the 19th century. In the last three
to four decades the warming rate has been locally increasing up to 0.02 K/year. It was also shown that the snow cover played
a dominant role in the penetration of the climate “signal” to depth and could considerably smooth down the subsurface response
to the changes occurred on the surface. 相似文献
5.
Čermák Vladimír Šafanda Jan Krešl Milan Dědeček Petr Bodri Louise 《Studia Geophysica et Geodaetica》2000,44(3):430-441
Long-term (1961 – 1996) meteorological air temperature series together with the reconstructed ground surface temperature histories, obtained by inverting borehole temperature-depth profiles, were used to project regional patterns of the recent (climate) warming rate on the territory of the Czech Republic. The characteristic magnitude of the warming rate of 0.02 –0.03 K/yr was confirmed by the results of several years of monitoring the temperature in two experimental boreholes. The monitoring of shallow temperatures at depths of about 30 –40 m, i.e. below the reach of the seasonal surface temperature variations, can serve as an alternative tool of direct quantitative assessment of the present warming rate. The data also seem to sustain a potential man-made component contributing to the more pronounced recent warming rate observed in the areas of large agglomeration. 相似文献
6.
Vladimir Cermak Louise Bodri Jan Safanda 《International Journal of Earth Sciences》2008,97(2):375-384
In the previous part of this work (Cermak, Safanda and Bodri, this volume p.MMM) we have described experimental data and quantified
the heterogeneity features of the microtemperature time series. The spectral analysis and the local growth of the second moment
technique revealed scaling structure of all observed time series generally similar and suggested the presence of two temperature
forming processes. The longer-scale part can be attributed to the heat conduction in compositional and structural heterogeneous
solid rocks, further affected by various local conditions. Short-scale temperature oscillations are produced by the intra-hole
fluid convection due to inherent instability of water column filling the hole. Here we present how the observational evidence
is supported by the results of the computer simulations. The exact modes of intra-hole convection may be different, ranging
from quasi-periodic (“quiescent”) state to close of turbulence. As demonstrated by numerical modeling and referred on laboratory
experiments, at higher Rayleigh numbers the periodic character of oscillation characteristic for “quiescent” regime is superseded
by stochastic features. This so called “oscillatory” convection occurs due to instability within the horizontal boundary layers
between the individual convectional cells. In spite of the fact that the basic convective cell motion is maintained and convection
is characterized by slow motion, the oscillatory intra-hole flow and corresponding temperature patterns exhibit typical features
of turbulence. The idea of boundary layer instability as a source of stochastic temperature fluctuations could explain many
distinct features of borehole temperatures that previously cannot be interpreted. 相似文献
7.
Vladimir Cermak Jan Safanda Louise Bodri 《International Journal of Earth Sciences》2010,99(6):1437-1451
Observational evidence proved that even when a borehole is in “fully” stabilized conditions, temperature data may exhibit
certain unrest resembling irregular oscillations in the order of hundredths or (in the extreme case) even tenths of degree.
Temperature was monitored in complicated hydrogeological conditions in the Yaxcopoil-1 hole (Chicxulub impact structure, Mexico).
Two experiments are reported: (a) 20-day monitoring when a logger was located in the center of the high temperature gradient
anomaly produced by the cold wave slowly propagating downwards and (b) simultaneous three-loggers 18-day monitoring with loggers
located above, in and below the anomaly. All observed temperature–time series displayed intermittent oscillations of temperature
with sharp gradients and large fluctuations over all observed time scales. While the “upper” and “lower” records revealed
quasi-periodic temperature variations, the “central” record shows fast temperature oscillations with strong up-and-down reversals,
all with amplitudes up to a few tenths of degree. The observed temperature–time series were processed by recurrence and recurrence
interval quantification as well as by spectral analyses. It is shown that fluid in a borehole, subject to thermal gradient,
is stable, as far as the gradient remains below a certain critical value. At higher Rayleigh numbers, the periodic character
of oscillations typical for “quiescent” regime is superseded by stochastic features. This “oscillatory” convection occurs
due to instability of the horizontal boundary layers. In the specific case of the Yaxcopoil hole, the time series above and
below the cold wave (characterized by relatively lower temperature gradients between 20 and 50 mK/m) contain a clear low frequency
component produced by tidal forcing. This component dominates over the high frequency domain (periods from 10–15 to 1 min),
which exhibit a scaling behavior. This pattern conspicuously changes in the center part of the cold wave, where the local
temperature gradient exceeds 200 mK/m and where tidal forcing composes only ~3% of the signal. 相似文献
8.
L. Bodri 《Theoretical and Applied Climatology》1995,51(1-2):51-58
Summary The structure of the temporal variability of temperature records has been investigated by means of different statistical methods including also fractal analysis. Data both from meteorological stations and averaged over wider networks show very similar behaviour; combine a long-run persistence (characterized by a fractal dimension ofD = 1.2–1.3) and short-run properties indicating high year-by-year variability. Synthetic temperature records were created with the use of Mandelbrot's fast fractional Gaussian noise generating algorithm. These fractal sets show the same stochastic properties as real temperature records do, and have even a very similar appearance. The results suggest that the fractal reconstruction algorithm could be used to extrapolate the present tendencies to the future and to forecast future fluctuations.With 8 Figures 相似文献
9.
Bertalan Bodri 《Physics of the Earth and Planetary Interiors》1974,9(2):141-146
The effect of viscosity on the phase of earth tides is computed. Computations are based on the general theory of the effect of viscosity of the mantle considered as a Maxwell body as it has been elaborated by Molodensky (1963). The problem is solved by the method of variation of constants, starting from the solution for the case of an ideally elastic, spherically symmetrical globe. The computations presented here cover the cases of the earth models B1 and B2 of Bullen and Haddon (1967). Love numbers k, l, h were computed for tides of second and third order, and values of phase delay due to viscosity were computed for tides of second order. 相似文献
10.
The knowledge of the present-day underground temperatures may be important in the assessments of the past climate change. The method of inversion of the temperature-depth records into the ground surface temperature history is briefly introduced by showing an example of synthetic data and illustrated by a review of existing results obtained from the inversion of temperature logs measured in holes in the Czech Republic. Underground temperatures observed in holes of the depth of at least 1000–1500 m seem to confirm the preinstrumental climate pattern of the past several thousand years. Most of shallower temperature records (500–800 m) revealed general warming of climate followed the Little Ice Age of the 17–18th centuries and a pronounced increase of the soil temperatures by at least 1 K since the beginning of this century. 相似文献