Geophysical Survey

About: Geophysical Survey is a facility organization based out in Obninsk, Russia. It is known for research contribution in the topics: Geology & Seismology. The organization has 308 authors who have published 256 publications receiving 3067 citations. The organization is also known as: Federal State Institution of Science Geophysical Survey of the Siberian Branch of the Russian Academy of Sciences.

Monitoring the deformation of a landslide with differential SAR interferometry using corner reflectors

Abstract: In order to monitor the surface deformation of Shuping landslide in the Yangtze River Three Gorges area, the method of differential SAR interferometry (DInSAR) using corner reflectors (CR) was applied. 12 CR, including 10 pyramidal corner reflectors (PCR) and 2 asymmetrical cubic corner reflectors (ACCR), were designed, made, and deployed on Shuping landslide. Based on the numerical test and the preliminary analyses of 5 ENVISAT ASAR images, we concluded that: 1) ACCR can provide strong response signal even without the best SAR look angle and is especially fit for the multi-angle applications of DInSAR; 2) given a simple phase model, the least square (LS) method can be used to analyze the CR's differential phase and get the accumulative deformation value.

Spectral characteristics of atmospheric pressure and electric field variations under severe weather conditions at high latitudes

Abstract: . The time-dependent relationships between atmospheric parameters (electric field, positive and negative conductivity, variations of atmospheric pressure) and different meteorological phenomena (rain, fogs, snowstorms, thunderstorms) were investigated through spectral analysis. These parameters were measured with help of a high-latitude computer-aided complex installed at Apatity (66.5 N, 33.4 E). The complex consists of three spaced microbarographs for measurements of atmospheric pressure variations in the range of periods from 1 s to 40 min, an instrument measuring the vertical component of the electric field, and instrument used for measurements of air conductivity and surface ozone. A computer-aided data-gathering system makes it possible to obtain information in the frequency range between 1 and 0.0001 Hz. The time-dependent frequency analysis showed that the spectral characteristics of both electric field and atmospheric pressure variations changed synchronously during severe weather conditions.

The Behavior of VLF/LF Variations Associated with Geomagnetic Activity, Earthquakes, and the Quiet Condition Using a Neural Network Approach.

Abstract: The neural network approach is proposed for studying very-low- and low-frequency (VLF and LF) subionospheric radio wave variations in the time vicinities of magnetic storms and earthquakes, with the purpose of recognizing anomalies of different types We also examined the days with quiet geomagnetic conditions in the absence of seismic activity, in order to distinguish between the disturbed signals and the quiet ones To this end, we trained the neural network (NN) on the examples of the representative database The database included both the VLF/LF data that was measured during four-year monitoring at the station in Petropavlovsk-Kamchatsky, and the parameters of seismicity in the Kuril-Kamchatka and Japan regions It was shown that the neural network can distinguish between the disturbed and undisturbed signals Furthermore, the prognostic behavior of the VLF/LF variations indicative of magnetic and seismic activity has a different appearance in the time vicinity of the earthquakes and magnetic storms

SAR interferometric phase filtering technique based on bivariate empirical mode decomposition

Abstract: The empirical mode decomposition (EMD) has been widely applied in filtering synthetic aperture radar interferograms. A noisy interferogram can be adaptively decomposed into different frequency modes by EMD. Then, the noise can be eliminated based on the partial reconstruction of relevant modes. However, most fine detail and noise of an interferogram often locate in the same mode, which will lead to an inaccurate estimation of noise level in a local region. In this paper, we proposed an improved filtering method based on bivariate EMD. The idea of our method is to decompose both the phase image and pseudo-coherence map of an interferogram using EMD. The filter level of an interferogram is then controlled by the parameters calculated from the bivariate EMD components. The quantitative results from both simulated and real data show that the bivariate EMD filtering method outperforms the original univariate EMD-based methods. It could achieve a balance between suppressing noise and preserving fine detail of a...

The main evolution of remote sensing for land resources of China in recent years

Abstract: The development of earth observation techniques has expanded and deepened the application area of remote sensing further. Meanwhile, the application on remote sensing for land resources has entered a new era marked by high spatial resolution, high spectral resolution and high temporal resolution. Nowadays, remote sensing techniques serve as an important support for the great discovery of geosciences and the modernization of geological work. The remote sensing satellites of our country develop to groups, networks and seriations; its application area develops to fine and quantitative direction; the recent researches both in basic field and application area develop to integration. In the following years, the need for remote sensing application will be more and more imminent. It is an inevitable tide for land remote sensing to use all-weather and multi-angle observation system by which we can observe the earth real-time to survey, suspect and research the resources, energy, and environment What is more, impractical hyper-spectral remote sensing system is an urgent technical platform problem to be solved for further application in remote sensing for resources and energy.