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Том 42, № 4 (2017)
- Год: 2017
- Статей: 7
- URL: https://bakhtiniada.ru/1068-3739/issue/view/14242
Article
Inertance of surface temperature variations
Аннотация
The index of inertance of surface temperature variations is proposed which supposedly reflects the damping effect of the ocean on the variations in atmospheric thermal conditions over the land. It is demonstrated that the climate variability and climate change are related to the index of inertance. Air temperature rose most intensively in the years of weak stabilizing effect of the ocean which restrains the climate warming. The general trend of the inertance weakening on the land in the second half of the 20th century led to the additional and more rapid warming and to the increase in climate extremity on the continents.
213-221
Analyzing the vortex as an integral formation: A case study for the blocking anticyclone of 2010
Аннотация
The peculiarities of blocking conditions and weather anomalies over the East European Plain in the summer of 2010 are considered using the EOF analysis and vorticity equation. The EOF analysis simulates the time series of the anticyclone as a whole using the principal modes of temporal variability. The vorticity equation is transformed into the specific form which enables assessing the contribution of different factors to the development and lasting existence of blocking conditions.
222-228
Characteristics of cyclones and anticyclones over Siberia in the late 20th and early 21st century
Аннотация
The characteristics of cyclones and anticyclones (number, pressure in the center, and duration) over the territory of Siberia (50°-70° N, 60°-110° E) in 1976-2011 obtained using surface weather charts are investigated. The relationship between the variability of these characteristics and the variability of surface air temperature is revealed.
229-237
A link between winter precipitation in Europe and the Arctic Sea ice, sea surface temperature, and atmospheric circulation
Аннотация
The spatial and temporal pattern of the link between the winter precipitation variability and variations in the North Atlantic sea surface temperature, the Arctic sea ice concentration, and 500 hPa geopotential height in the Northern Hemisphere is analyzed for the period of 1952-2012. The analysis reveals two principal modes of covariability in the analyzed characteristics. The first mode which explains the most part of covariability, is related to the impact of the North Atlantic Oscillation. The second mode indicates the significant contribution of the Atlantic Multidecadal Oscillation associated with winter precipitation anomalies of the same sign in Europe with the maxima on the East European Plain and in the Balkan region during the positive phase of AMO.
238-247
A statistical model for describing the texture of cloud cover images from satellite data
Аннотация
A statistical model is proposed which describes the texture of the images of 25 types of clouds from the MODIS satellite data with the spatial resolution of 250 m. A technique is presented which compiles the sets of image segments with typical textures for different cloud types. To describe the texture, the following statistical methods are applied: Gray-Level Co-occurrences Matrix, Gray-Level Difference Vector, and Sum and Difference Histogram. The correlation analysis is used to form the sets of informative textural features for the images of different cloud types. Two-parameter distribution laws and the estimates of their parameters are presented which describe fluctuations in the efficient set of textural features of different cloud types.
248-257
Wave interpretation of major Baltic inflows
Аннотация
The water dynamics in the straits between the North and Baltic seas during two major Baltic inflows that took place in the January of 1993 and 2003 is investigated using satellite altimetry data. It is found that the water mass surge to the eastern coast of the North Sea occurs before the beginning of the major Baltic inflow, and the sea level difference between the two seas is ~60 cm. Low-frequency fluctuations in the sea level and its wave parameters are studied. The wavelet analysis and the frequency-directed spectral analysis reveal the wave nature of the mechanisms leading to major Baltic inflows. The empirical characteristics of the obtained low-frequency waves are compared with the theoretical dispersion relations for the gradient-vorticity waves. Sea level variations during major Baltic inflows in the Danish Straits are identified as baroclinic Rossby waves. The analysis of cyclonic activity in the Northern Hemisphere demonstrated that stationary cyclones were observed during the inflows; this proves the feasibility of the resonance mechanism of the generation of major Baltic inflows.
258-266
Hydrodynamic modeling of floods in Saint Petersburg considering the operating dam
Аннотация
The Baltic Sea level is computed from the BALT-P three-dimensional hydrodynamic model at the grid with the horizontal resolution of 2 nautical miles, and the computation for the top of the Gulf of Finland is provided at the grid with the spatial resolution of 90 m. The sea motion is induced by the air pressure gradients and wind stress values from the HIRLAM model forecast specified on the sea surface. The sea level is calculated for three floods in Saint Petersburg with account that each of eight spillways of the dam closed and opened not instantly but during the prescribed period of time. It is revealed that the BALT-P model simulates the sea level well during three floods in Saint Petersburg considering the operating dam. The model can be used for the sea level forecasting in Saint Petersburg based on the HIRLAM atmospheric model data with the lead time of 60 hours.
267-274