We present observations of narrowband subionospheric VLF transmitter signals on 20 March 2001, exhibiting coherent fluctuations of over 1 dB peak to peak. Spectral analysis shows that the fluctuations have periods of 1–4min and are largely coherent. The subionospheric propagation path of the signal from Puerto Rico to Colorado passes over two regions of convective and lightning activity, as obs...

Initial theoretical studies of multi-spacecraft radio tomographic imaging of the magnetosphere have shown the potential scientific value of the technique. We report a series of multistatic radio propagation experiments with the goal of testing and verifying the capabilities of radio tomography. These experiments focused specifically on measuring the plasma-induced rotation of the wave polarizat...

the existing theory for wave propagation through a soil layer are not compatible with the real soil layers because in the theory the layers are flat and the sub-layers are parallel, while in real the soil layers are not flat and they may not be parallel. thus, wave propagations through a corrugated interface are so important. in this paper, a two-dimensional sh-wave propagation through a corrug...

The generalized coupled thermo-viscoelasticity of hollow sphere subjected to thermal symmetric shock load is presented in this paper. To overcome the infinite speed of thermal wave propagation, the Lord-Shulman theory is considered. Two coupled equations, namely, the radial equation of motion and the energy equation of a hollow sphere are obtained in dimensionless form. Resulting equations are ...

The radio holography methodology may be applied in the scientific programs for future small satellite that will use radio signals emitted by radio navigation, radio communication satellites for precise measuring effects of radio waves propagation at low elevation angles and for global monitoring of radio communication channels passed through the atmosphere and ionosphere. Another task consists ...

a considerable part of precipitation falls in the form of snow in golestan watershed. in turn, snowmelt plays a significant role in surface runoff, groundwater feeding and flood propagation in this area. snow cover area (sca) as an indicator of stored water can be implemented for temporal and spatial monitoring of snowmelt in the hydrological models. to monitor spatial and temporal variation of...

Wind and temperature observations in the mesosphere and lower thermosphere (MLT) from the Upper Atmosphere Research Satellite (UARS) reveal strong seasonal variations of tides, a dominant component of the MLT dynamics. Simulations with the Spectral mesosphere/lower thermosphere model (SMLTM) for equinox and solstice conditions are presented and compared with the observations. The diurnal tide i...

this paper presents time domain fundamental solutions for the extended biot's dynamic formulations of two-dimensional (2d) unsaturated poroelasticity. unsaturated porous media is considered as a porous media in which the voids are saturated with two immiscible fluids, i.e. liquid and gas. at first, the corresponding explicit laplace transform domain fundamental solution is obtained in term...