Monitoring of the eruption of the Sarychev Peak Volcano in Matua Island in 2009 (central Kurile islands)     

Levin  B. W.  Rybin  A. V.  Vasilenko  N. F.  Prytkov  A. S.  Chibisova  M. V.  Kogan  M. G.  Steblov  G. M.  Frolov  D. I. 《Doklady Earth Sciences》2010,435(1):1507-1510

In June 2009, one of the greatest eruptions of the Sarychev Peak volcano in Matua Island (48°06′ N, 153°12′ E) for the recent historical period occurred. With the help of satellite sounding methods, the first signs of volcanic activity were recorded and all the stages of the explosive eruption were traced. During the expeditionary investigations in the active volcano, unique data on the character of the eruption were obtained. The volume of erupted material was 0.4 cubic km, which lead to an increased area of Matua Island by 1.4 square km. The GPS observation station set at the distance of 7 km from the volcano recorded the rapid displacement of the Earths’s surface during the first two days of the active phase of eruption. This eruption of the Sarychev Peak volcano occurred 2.5 years after the catastrophic Simushir earthquakes in the period of intensive relaxation of stresses in the middle of the central part of the Kurile island arc.  相似文献   

The Copernican principle in compact space–times     

John D. Barrow  Janna Levin 《Monthly notices of the Royal Astronomical Society》2003,346(2):615-618

Copernicus realized that we are not at the centre of the Universe. A universe made finite by topological identifications introduces a new Copernican consideration: while we may not be at the geometric centre of the Universe, some galaxy could be. A finite universe also picks out a preferred frame: the frame in which the universe is smallest. Although we are not likely to be at the centre of the Universe, we must live in the preferred frame (if we are at rest with respect to the cosmological expansion). We show that the preferred topological frame must also be the comoving frame in a homogeneous and isotropic cosmological space–time. Some implications of topologically identifying time are also discussed.  相似文献   

Simulation of gas dynamics and radiation in volcanic plumes on Io     

J. Zhang  D.B. Goldstein  N.E. Gimelshein  D.A. Levin 《Icarus》2003,163(1):182-197

Modeling results of volcanic plumes on Jupiter’s moon Io are presented. Two types of low density axisymmetric SO₂ plume flows are modeled using the direct simulation Monte Carlo (DSMC) method. Thermal radiation from all three vibrational bands and overall rotational lines of SO₂ molecules is modeled. A high resolution computation of the flow in the vicinity of the vent was obtained by multidomain sequential calculation to improve the modeling of the radiation signature. The radiation features are examined both by calculating infrared emission spectra along different lines-of-sight through the plume and with the DSMC modeled emission images of the whole flow field. It is found that most of the radiation originates in the vicinity of the vent, and non-LTE (non-local-thermodynamic equilibrium) cooling by SO₂ rotation lines exceeds cooling in the v₂ vibrational band at high altitude.In addition to the general shape of the plumes, the calculated average SO₂ column density (∼10¹⁶ cm⁻²) over a Pele-type plume and the related frost-deposition ring structure (at R ∼ 500 km from the vent) are in agreement with observations. These comparisons partially validate the modeling. It is suggested that an observation with spatial resolution of less than 30 km is needed to measure the large spatial variation of SO₂ near a Pele-type plume center. It is also found that an influx of 1.1 × 10²⁹ SO₂ s⁻¹ (or 1.1 × 10⁴ kg s⁻¹) is sufficient to reproduce the observed SO₂ column density at Pele. The simulation results also show some interesting features such as a multiple bounce shock structure around Prometheus-type plumes and the frost depletion by plume-induced erosion on the sunlit side of Io. The model predicts the existence of a canopy shock, a ballistic region inside the Pele-type plume, and the negligible effect of surface heating by plume emission.  相似文献   

Starbursts near supermassive black holes: young stars in the Galactic Centre, and gravitational waves in LISA band     

Yuri Levin 《Monthly notices of the Royal Astronomical Society》2007,374(2):515-524

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Quasi-linear model for the plasma mechanism of narrow-band microwave burst generation     

B. N. Levin  V. F. Mel'Nikov 《Solar physics》1993,148(2):325-340

Characteristic features of the plasma model for radio emission from the extending fronts of solar flare energy release are studied. It is shown that the electron distribution is formed near the thermal fronts as stationary beam injection through the boundary into the cold plasma semi-space. A principal new result is a conclusion about the localization of a plasma turbulence region — the source of emission in a narrow layer before the thermal front, that makes it possible to explain the burst narrow-band feature in a natural way. Wide capabilities of the flare loop structure analysis using the narrow-band emission parameters are demonstrated.  相似文献   

Macrobenthic community response to copper in Shelter Island Yacht Basin, San Diego Bay, California     

Neira C  Mendoza G  Levin LA  Zirino A  Delgadillo-Hinojosa F  Porrachia M  Deheyn DD 《Marine pollution bulletin》2011,62(4):701-717

We examined Cu contamination effects on macrobenthic communities and Cu concentration in invertebrates within Shelter Island Yacht Basin, San Diego Bay, California. Results indicate that at some sites, Cu in sediment has exceeded a threshold for “self defense” mechanisms and highlight the potential negative impacts on benthic faunal communities where Cu accumulates and persists in sediments. At sites with elevated Cu levels in sediment, macrobenthic communities were not only less diverse but also their total biomass and body size (individual biomass) were reduced compared to sites with lower Cu. Cu concentration in tissue varied between species and within the same species, reflecting differing abilities to “regulate” their body load. The spatial complexity of Cu effects in a small marina such as SIYB emphasizes that sediment-quality criteria based solely on laboratory experiments should be used with caution, as they do not necessarily reflect the condition at the community and ecosystem levels.  相似文献   

Editorial—The 3rd International Workshop on Modeling the Ocean (IWMO 2011)     

Lie-Yauw Oey  Tal Ezer  Bo Qiu  Jarle Berntsen  Ruoying He 《Ocean Dynamics》2013,63(2-3):307-309

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Semantically based reclassification of Danish land-use and land-cover information     

Martin Rudbeck Jepsen  Gregor Levin 《International journal of geographical information science》2013,27(12):2375-2390

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Soil loss,water ponding and sediment deposition variations as a consequence of rainfall intensity and land use: a multi‐criteria analysis     

Tal Svoray  Shimon Ben‐Said 《地球表面变化过程与地形》2010,35(2):202-216

Prediction of areas prone to land degradation in agricultural catchments is a complex task. This is due to the difficulties encountered in data gathering over wide regions and in the translation of existing scientific knowledge to a quantitative and spatially explicit risk assessment system. This paper incorporates the use of remotely sensed data, terrain analysis and a multi‐criteria mechanism for evaluating risks of soil loss, water ponding, and sediment deposition in a mid‐size agricultural Mediterranean catchment, under 80 years of intensive cultivation. The research uses simulations to study the effect of topographic attributes, soil characteristics, vegetation cover, rainfall intensity and human activities on the three above‐mentioned processes. The results show that, from the methodological point of view, the integration of knowledge from several experts yields better predictive results than relying on a single expert, even the one found to be most consistent. Also, the use of a simple weighted linear combination was more useful than the more sophisticated computerized programming technique. From the phenomenological point of view, the increase in rainfall intensity and land‐use transformation from orchard to field‐crops has led to a significant increase in soil loss and sediment yield, while extreme changes in tillage direction have only yielded minor changes in water ponding. The developed system's predictive capabilities also show that the outcomes can be used as a basis for decisions on catchment management in regions of high environmental sensitivity. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Editorial—International Workshop on Modeling the Ocean (IWMO) special issue in Ocean Dynamics     

Lie-Yauw Oey  Tal Ezer  Yasumasa Miyazawa  Chau-Ron Wu 《Ocean Dynamics》2010,60(2):299-300

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