Using the linear theory of waves in a compressible atmosphere located in a gravitational field, we found a family of sound speed profiles for which the wavefield can be represented by a traveling wave with no reflection. The vertical flux of wave energy on these nonreflected profiles is retained, which proves that the energy transfer may occur over long distances.
A computational method for diagnosing threedimensional atmospheric fronts from temperature, wind, and geopotential fields on a threedimensional regular grid is proposed. The criterion, which serves for the diagnosis of atmospheric fronts, is discussed. The weights of the input information about the mentioned fields are optimized based on the maximal difference between the correlation functions for (a) pairs of parti cles separated by the front and (b) pairs from one synoptic mass. These weights were different for different baric levels. The correlation functions and the optimization of weights were estimated on the basis of the archive of fields of the NCEP objective analysis on the halfdegree latitude–longitude grid and data from aerological observations. The results of numerical experiments on the construction of atmospheric fronts are presented. Applying the described method to fields predicted for a term of up to 36 h showed that errors in the prognostic models introduce a relatively weak distortion into the geometry of atmospheric fronts.
This paper describes a space experiment that is planned to be performed within the framework of the Russian project of the microsatellite CHIBIS AI to meaure ionospheric signal delays to determine the electron density and spatial fluctuations of the ionospheric and magnetospheric plasma. The measurements will be conducted by the phase interferometer method at two levels using signals from the onboard in-phase transmitters and GPS/GLONASS signals. The location of the radiation sources at two levels will make it possible to separate plasma variations in the ionosphere and inner magnetosphere-plasmasphere. The experimental results are of interest both for solving fundamental problems of near-Earth plasma physics and applied problems to improve positioning accuracy using global navigation systems.
This paper describes a space experiment that is planned to be performed within the framework of
the Russian project of the microsatellite CHIBIS AI to meaure ionospheric signal delays to determine the
electron density and spatial fluctuations of the ionospheric and magnetospheric plasma. The measurements
will be conducted by the phase interferometer method at two levels using signals from the onboard in-phase
transmitters and GPS/GLONASS signals. The location of the radiation sources at two levels will make it pos-
sible to separate plasma variations in the ionosphere and inner magnetosphere–plasmasphere. The experi-
mental results are of interest both for solving fundamental problems of near-Earth plasma physics and applied
problems to improve positioning accuracy using global navigation systems.
Internal gravity wave (IGW) data obtained during the passage of atmospheric fronts over the Moscow region in June–July 2015 is analyzed. IGWs were recorded using a group of four microbarographs (developed at the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences) located at distances of 7 to 54 km between them. Regularities of variations in IGW parameters (spatial coherence, characteristic scales, propagation direction, horizontal propagation velocity, and amplitudes) before, during, and after the passage of an atmospheric front over the observation network, when the observation network finds itself inside the cyclone and outside the front, are studied. The results may be useful in studying the relationships between IGW effects in different physical fields at different atmospheric heights. It is shown that, within periods exceeding 30 min, IGWs are coherent between observation points horizontally spaced at distances of about 60 km (coherence coefficient is 0.6–0.9). It is also shown that there is coherence between wave fluctuations in atmospheric pressure and fluctuations in horizontal wind velocity within the height range 60–200 m. A joint analysis of both atmospheric pressure and horizontal wind fluctuations has revealed the presence of characteristic dominant periods, within which cross coherences between fluctuations in atmospheric pressure and wind velocity have local maxima. These periods are within approximate ranges of 20–29, 37–47, 62–72, and 100–110 min. The corresponding (to these dominant periods) phase propagation velocities of IGWs lie within an interval of 15–25 m/s, and the horizontal wavelengths vary from 52 to 99 km within periods of 35 to 110 min, respectively.
Observation data on the September 5, 1971, earthquake that occurred near the Moneron Island (Sakhalin) have been analyzed and a numerical simulation of the tsunami induced by this earthquake is conducted. The tsunami source identified in this study indicates that the observational data are in good agreement with the results of calculations performed on the basis of shallow-water equations
Tsunami forecast possibilities for areas with a small base of historical tsunamis have been discussed using the Probabilistic Tsunami Hazard Assessment (PTHA) method, which is based on a statistical analysis of a sufficiently large number of real and predictive earthquakes with a subsequent calculation of possible tsunami waves. This method has been used for a long-term tsunami hazard assessment on the Mediterranean coast of Egypt. The predicted wave heights have been shown to vary along the coastline due to the inhomogeneity of the coastal topography and specific features of the tsunami radiation pattern in the sea. The predicted wave heights for 1000 years vary in the range between 0.8 and 3.4 m.