Global assessments of the NCEP Ensemble Forecast System using altimeter data     

Campos  Ricardo Martins  Alves  Jose-Henrique G.M.  Penny  Stephen G.  Krasnopolsky  Vladimir 《Ocean Dynamics》2020,70(3):405-419

Ocean Dynamics - Forecasts of 10-m wind (U10) and significant wave height (Hs) from the National Centers for Environmental Prediction (NCEP) Ensemble Forecast System are evaluated using altimeter...  相似文献   

Observations of near-inertial oscillations along the Brazilian continental shelf break     

de Freitas  Pedro Paulo  Amorim  Felipe de Luca Lopes  Mill  Guilherme Nogueira  da Costa  Vladimir Santos  Gabioux  Mariela  Cirano  Mauro  Paiva  Afonso de Moraes 《Ocean Dynamics》2019,69(10):1203-1215

Ocean Dynamics - Near-inertial oscillations (NIO) are intermittent motions with a frequency close to the inertial frequency and represent an important fraction of the energy to the currents in the...  相似文献   

On the Description of Transverse Wave Propagation Along Thin Magnetic Flux Tubes     

Tsap  Yu. T.  Stepanov  A. V.  Kopylova  Yu. G. 《Geomagnetism and Aeronomy》2018,58(7):942-946

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Mesoscale eddies and baroclinic instability over the eastern Sakhalin shelf of the Sea of Okhotsk: a model-based analysis     

Dmitry V. Stepanov 《Ocean Dynamics》2018,68(10):1353-1370

Based on an eddy-permitting numerical model, the mesoscale variability in the East-Sakhalin Current is investigated during the winter-spring period. Analysis of necessary conditions for the development of baroclinic instability showed that the nearshore component of the East-Sakhalin Current is potentially baroclinic unstable in the first half-year. The simulated circulation uncovered a generation of anticyclonic eddies on the eastern Sakhalin shelf. It was established that a spatial scale of these eddies and the first baroclinic Rossby radius of deformation are values of the same order; a lifetime of these eddies varies from 4 to 6 weeks, given the Rossby number varies from 0.05 to 0.2. Analysis of the rate of eddy energy conversion on the eastern Sakhalin shelf showed that the generation of the revealed mesoscale eddies results from, mainly, baroclinic instability, whereas barotropic instability can be both favoring and preventing to the generation of these eddies.  相似文献   

Eddy energy sources and mesoscale eddies in the Sea of Okhotsk     

Dmitry V. Stepanov  Nikolay A. Diansky  Vladimir V. Fomin 《Ocean Dynamics》2018,68(7):825-845

Based on eddy-permitting ocean circulation model outputs, the mesoscale variability is studied in the Sea of Okhotsk. We confirmed that the simulated circulation reproduces the main features of the general circulation in the Sea of Okhotsk. In particular, it reproduced a complex structure of the East-Sakhalin current and the pronounced seasonal variability of this current. We established that the maximum of mean kinetic energy was associated with the East-Sakhalin Current. In order to uncover causes and mechanisms of the mesoscale variability, we studied the budget of eddy kinetic energy (EKE) in the Sea of Okhotsk. Spatial distribution of the EKE showed that intensive mesoscale variability occurs along the western boundary of the Sea of Okhotsk, where the East-Sakhalin Current extends. We revealed a pronounced seasonal variability of EKE with its maximum intensity in winter and its minimum intensity in summer. Analysis of EKE sources and rates of energy conversion revealed a leading role of time-varying (turbulent) wind stress in the generation of mesoscale variability along the western boundary of the Sea of Okhotsk in winter and spring. We established that a contribution of baroclinic instability predominates over that of barotropic instability in the generation of mesoscale variability along the western boundary of the Sea of Okhotsk. To demonstrate the mechanism of baroclinic instability, the simulated circulation was considered along the western boundary of the Sea of Okhotsk from January to April 2005. In April, the mesoscale anticyclonic eddies are observed along the western boundary of the Sea of Okhotsk. The role of the sea ice cover in the intensification of the mesoscale variability in the Sea of Okhotsk was discussed.  相似文献   

Seismic network detection probability assessment using waveforms and accounting to event association logic     

Vladimir Pinsky  Avi Shapira 《Journal of Seismology》2017,21(1):69-82

The geographical area where a seismic event of magnitude M?≥?M _t is detected by a seismic station network, for a defined probability is derived from a station probability of detection estimated as a function of epicentral distance. The latter is determined from both the bulletin data and the waveforms recorded by the station during the occurrence of the event with and without band-pass filtering. For simulating the real detection process, the waveforms are processed using the conventional Carl Johnson detection and association algorithm. The attempt is presented to account for the association time criterion in addition to the conventional approach adopted by the known PMC method.  相似文献   

Electrical triggering of earthquakes: results of laboratory experiments at spring-block models          下载免费PDF全文

Victor A. Novikov  Vladimir I. Okunev  Vadim N. Klyuchkin  Jing Liu  Yuri Ya. Ruzhin  Xuhui Shen 《地震科学（英文版）》2017,30(4):167-172

Recently published results of field and laboratory experiments on the seismic/acoustic response to injection of direct current(DC) pulses into the Earth crust or stressed rock samples raised a question on a possibility of electrical earthquake triggering. A physical mechanism of the considered phenomenon is not clear yet in view of the very low current density(10~(-7)–10~(-8) A/m~2) generated by the pulsed power systems at the epicenter depth(5–10 km) of local earthquakes occurred just after the current injection. The paper describes results of laboratory‘‘earthquake' triggering by DC pulses under conditions of a spring-block model simulated the seismogenic fault. It is experimentally shown that the electric triggering of the laboratory ‘‘earthquake'(sharp slip of a movable block of the spring-block system) is possible only within a range of subcritical state of the system, when the shear stress between the movable and fixed blocks obtains 0.98–0.99 of its critical value. The threshold of electric triggering action is about 20 A/m~2 that is 7–8 orders of magnitude higher than estimated electric current density for Bishkek test site(Northern Tien Shan, Kirghizia) where the seismic response to the man-made electric action was observed. In this connection, the electric triggering phenomena may be explained by contraction of electric current in the narrow conductive areas of the faults and the corresponding increase in current density or by involving the secondary triggering mechanisms like electromagnetic stimulation of conductive fluid migration into the fault area resulted in decrease in the fault strength properties.  相似文献   

Empirical model for estimating Fourier amplitude spectra of ground acceleration in Taiwan region     

Vladimir Sokolov  Chin‐Hsiung Loh  Kuo‐Liang Wen 《地震工程与结构动力学》2000,29(3):339-357

A collection of ground‐motion recordings (1070 acceleration records) of moderate (5.1⩽M_L⩽6.5) earthquakes obtained during the execution of the Taiwan Strong Motion Instrumentation Program (TSMIP) since 1991 was used to study source scaling model and attenuation relations for a wide range of earthquake magnitudes and distances and to verify the models developed recently for the Taiwan region. The results of the analysis reveal that the acceleration spectra of the most significant part of the records, starting from S‐wave arrival, can be modelled accurately using the Brune's ω‐squared source model with magnitude‐dependent stress parameter Δσ, that should be determined using the recently proposed regional relationships between magnitude (M_L) and seismic moment (M₀) and between M₀ and Δσ. The anelastic attenuation Q of spectral amplitudes with distance may be described as Q=225 ƒ^1.1 both for deep (depth more than 35 km) and shallow earthquakes. The source scaling and attenuation models allow a satisfactory prediction of the peak ground acceleration for magnitudes 5.1⩽M⩽6.5 and distances up to about 200 km in the Taiwan region, and may be useful for seismic hazard assessment. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Mafic Intrusions of ca. 2400 Ма Large Igneous Province in the Belomorian Mobile Belt: First Baddeleyite U–Pb ID-TIMS Data     

Stepanova  A. V.  Salnikova  E. B.  Samsonov  A. V.  Egorova  S. V.  Stepanov  V. S. 《Doklady Earth Sciences》2020,493(2):617-620

Doklady Earth Sciences - U–Pb ID-TIMS dating of igneous baddeleyite from metamorphosed coronitic gabbronorites in the сentral part of the Belomorian mobile belt, Fennoscandian shield...  相似文献