NO<Subscript>2</Subscript> content variations near St. Petersburg as inferred from ground-based and satellite measurements of scattered solar radiation     

A. V. Poberovskii  A. V. Shashkin  D. V. Ionov  Yu. M. Timofeev 《Izvestiya Atmospheric and Oceanic Physics》2007,43(4):505-513

An automatic spectral complex developed at the Institute of Physics, St. Petersburg State University, is described. This complex is used for regular ground-based spectroscopic measurements of the total NO₂ content in the vertical column of the atmosphere during the twilight and daylight hours of the day near St. Petersburg (Petrodvorets). In 2004–2006, a number of ground-based twilight measurements of the total NO₂ content were obtained near St. Petersburg, and variations in the NO₂ content in the troposphere were estimated from the results of daytime ground-based measurements. An example of the spatial annual mean distribution of the NO₂ content (central and northern Europe, northwestern Russia) based on the data of satellite measurements over the period 2003–2005 is presented. This example demonstrates the main sources of anthropogenic pollution. An increase in the mean annual contents of tropospheric NO₂ near Moscow and St. Petersburg is preliminarily estimated for the entire period of satellite observations with the GOME instrument at about 30–40% over ten years.  相似文献   

Transcontinental tidal transect: European Atlantic coast-Southern Siberia-Russian Pacific coast     

V. Yu. Timofeev  B. Ducarme  M. van Ruymbeke  P. Yu. Gornov  M. Everaerts  E. I. Gribanova  V. A. Parovyshnii  V. M. Semibalamut  G. Woppelmann  D. G. Ardyukov 《Izvestiya Physics of the Solid Earth》2008,44(5):388-400

The paper presents results of measurements with digital tidal LaCoste-Romberg gravimeters on the European Atlantic coast-Southern Siberia-Russian Pacific coast transect in 1995–2005. The transect includes four West European (Chizé, Ménesplet, Mordelles, and Wikle), two South Siberian (Klyuchi and Talaya), and two Far Eastern (Zabakalskoe and Yuzhno-Sakhalinsk) stations. Gravimetric measurements at the Talaya station (SW Baikal rift zone) are supplemented by long-term laser extensometer observations. The position of the stations within the rectangle (45°–55°N, 0.4°–142°E) allows one to assess existing tidal strain models (WD93 and DDW99) and various ocean tide models (SCW80, CSR3, FES95, ORI96, CSR4, FES02, GOT00, NAO99, and TPX06). Data of intracontinental stations (with a small ocean effect at distances of 2000–3000 km) agree well with the DDW99 tidal strain model (with regard to the mantle viscosity). The uncertainty of digital tidal gravity measurements is 0.25%. Results of laser extensometer measurements are at the same accuracy level. Then, the Love and Shida numbers calculated at midlatitudes of the intracontinental zone of Eurasia from combined data are h = 0.6077 ± 0.0008, k = 0.3014 ± 0.0001, and l = 0.0839 ± 0.0001. The analysis of results of Pacific and Atlantic stations located at distances of 30–300 km from the ocean showed that the FES02, CSR4, GOT00, NAO99, and TPX06 ocean tide models are preferable.  相似文献   

Hot Neutral H in the Heliosphere: Elastic H-H, H-p Collisions     

Vladislav V. Izmodenov  Yury G. Malama  Alexandr P. Kalinin  Mike Gruntman  Rosine Lallement  Irina P. Rodionova 《Astrophysics and Space Science》2000,274(1-2):71-76

Williams et al. (1997) have suggested that a population of hot hydrogen atoms is created in the heliosphere through elastic H-H collisions between energetic `solar' atoms (neutralized solar wind) and interstellar atoms. They used a BGK-like approximation (Bhatnagar et al., 1954) for the Boltzmann collision term and the collision cross sections suggested by Dalgarno (1960). We show that both assumptions result in a significant overestimation of the the H-H collision effect. On the basis of calculated momentum transfer cross-sections for elastic H-H collisions, we argue that elastic H-H and H-p collisions cannot produce hot H atoms in the heliosphere. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Estimation of coseismic deformation, poroelasticity, and fracturing of rocks from the data on water level in a borehole     

V. Yu. Timofeev  D. G. Ardyukov  E. V. Boiko  A. V. Timofeev  A. V. Yaroshevich  P. Yu. Gornov 《Izvestiya Physics of the Solid Earth》2012,48(7-8):640-652

Variations in the water level in boreholes emerge in response to tidal, baric, and tectonic forcing. We analyze the data on atmospheric pressure and water level recorded in the boreholes located in the mid-latitude Eurasia (45°?C55°N) from Western Europe (Belgium, Uccle), Siberia (coastal area of Lake Baikal, Talaya River) to Far Eastern Russia (the Bychikha borehole near Khabarovsk and the boreholes on the Kamchatka Peninsula and Kurils). The response of the water level in a borehole to periodic tidal and baric impacts is investigated. In this case, water level variations reflect areal (lateral) and vertical deformations, which allows estimating the elastic moduli and porosity of the confined aquifer in a static model. Measurements in the boreholes drilled in the fractured solid rock enable determining the geometric parameters of the fractures. The possibility to apply the method for evaluating tectonic deformations is discussed. Application of tidal coefficients of boreholes for determining the coseismic deformation is demonstrated by the example of the Kultuk earthquake (Lake Baikal, August 27, 2008, M = 6.3).  相似文献   

Using artificial neural networks in the temperature and humidity sounding of the atmosphere     

A. V. Polyakov  Yu. M. Timofeev  Ya. A. Virolainen 《Izvestiya Atmospheric and Oceanic Physics》2014,50(3):330-336

The application of the radiative data inversion technique based on artificial neural networks (ANN) for the meteorological satellite sounding of the atmosphere is described. To increase the efficiency of solving inverse problems, the principal component method is used for the temperature and humidity profiles, as well as for IR radiation spectra, which allows the problem dimensionalities to be reduced substantially. Based on numerical experiments, errors of the temperature and humidity sounding are analyzed from the spectra of outgoing IR radiation (that were measured by the IKFS-2 instrument onboard the Meteor Russian satellite) using the iterative physical-mathematical (IPM) algorithm, multiple linear regression (MLR), and ANN-based methods. Appreciable advantages of the ANN-based method are revealed as compared to the MLR method. Therefore, in temperature sounding, the MLR method has a markedly large error at heights of 1–12 km (a difference of up to 1 K), while the IPM algorithm has almost the same error as the ANN method. The humidity determination error is about 10% when the ANN method is used at heights of 0–12 km. The IPM approach yields approximately the same error in the lower troposphere, but as the height increases the advantages of the ANN method grow.  相似文献   

Quasi-satellite orbits in the general context of dynamics in the 1:1 mean motion resonance: perturbative treatment     

Vladislav V. Sidorenko  Anatoly I. Neishtadt  Anton V. Artemyev  Lev M. Zelenyi 《Celestial Mechanics and Dynamical Astronomy》2014,120(2):131-162

Our investigation is motivated by the recent discovery of asteroids orbiting the Sun and simultaneously staying near one of the Solar System planets for a long time. This regime of motion is usually called the quasi-satellite regime, since even at the times of the closest approaches the distance between the asteroid and the planet is significantly larger than the region of space (the Hill’s sphere) in which the planet can hold its satellites. We explore the properties of the quasi-satellite regimes in the context of the spatial restricted circular three-body problem “Sun–planet–asteroid”. Via double numerical averaging, we construct evolutionary equations which describe the long-term behaviour of the orbital elements of an asteroid. Special attention is paid to possible transitions between the motion in a quasi-satellite orbit and the one in another type of orbits available in the 1:1 resonance. A rough classification of the corresponding evolutionary paths is given for an asteroid’s motion with a sufficiently small eccentricity and inclination.  相似文献   

Determination of the total ozone content from data of satellite IR Fourier-spectrometer     

A.?S.?Garkusha  A.?V.?PolyakovEmail author  Yu.?M.?Timofeev  Ya.?A.?Virolainen 《Izvestiya Atmospheric and Oceanic Physics》2017,53(4):433-440

Examples of retrieval of the total ozone content (TOC) from the spectra of outgoing thermal radiation measured by the IRFS-2 device on the Meteor-M no. 2 meteorological satellite are presented. The technique, developed by the authors and based on an artificial neural network (ANN) approach with the use of TOC measurements by the satellite OMI device, is applied. A comparison of the results with the data of independent TOC measurements has shown their agreement within 2–5% for global ensemble and within 3–6% for separate latitudes and seasons. The errors estimated for IRFS-2 TOC measurements are close to the errors in measurements by a similar IASI device from the MetOp (EUMETSAT) satellite.  相似文献