Automatically positioning microseismic sources in mining by the stereo tomographic method using full wavefields

For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.

The Role of Barrier Layer in Southeastern Arabian Sea During the Development of Positive Indian Ocean Dipole Events

Using data from Argo and simple ocean data assimilation (SODA), the role of the barrier layer (BL) in the southeastern Arabian Sea (SEAS: 60°E-75°E, 0°-10°N) is investigated during the development of positive Indian Ocean Dipole (IOD) events from 1960 to 2008. It is found that warmer sea surface temperature (SST) in the northern Indian Ocean appears in June in the SEAS. This warm SST accompanying anomalous southeastern wind persists for six months and a thicker BL and a corresponding thinner mixed layer in the SEAS contribute to the SST warming during the IOD formation period. The excessive precipitation during this period helps to form a thicker BL and a thinner mixed layer, resulting in a higher SST in the SEAS. Warm SST in the SEAS and cold SST to the southeast of the SEAS intensify the southeasterly anomaly in the tropical Indian Ocean, which transports more moisture to the SEAS, and then induces more precipitation there. The ocean-atmosphere interaction process among wind, precipitation, BL and SST is very important for the anomalous warming in the SEAS during the development of positive IOD events.

ENSO cycle and climate anomaly in China

The inter-annual variability of the tropical Pacific Subsurface Ocean Temperature Anomaly （SOTA） and the associated anomalous atmospheric circulation over the Asian North Pacific during the E1 Nifio-Southern Oscillation （ENSO） were investigated using National Centers for Environmental Prediction/ National Center for Atmospheric Research （NCEP/NCAR） atmospheric reanalysis data and simple ocean data simulation （SODA）. The relationship between the ENSO and the climate of China was revealed. The main results indicated the following： 1） there are two ENSO modes acting on the subsurface tropical Pacific. The first mode is related to the mature phase of ENSO, which mainly appears during winter. The second mode is associated with a transition stage of the ENSO developing or decaying, which mainly occurs during summer; 2） during the mature phase of E1Nifio, the meridionality of the atmosphere in the mid-high latitude increases, the Aleutian low and high pressure ridge over Lake Baikal strengthens, northerly winds prevail in northern China, and precipitation in northern China decreases significantly. The ridge of the Ural High strengthens during the decaying phase of E1 Nifio, as atmospheric circulation is sustained during winter, and the northerly wind anomaly appears in northern China during summer. Due to the ascending branch of the Walker circulation over the western Pacific, the western Pacific Subtropical High becomes weaker, and south-southeasterly winds prevail over southern China. As a result, less rainfall occurs over northern China and more rainfall over the Changjiang River basin and the southwestern and eastern region of Inner Mongolia. The flood disaster that occurred south of Changjiang River can be attributed to this. The La Nifm event causes an opposite, but weaker effect; 3） the ENSO cycle can influence climate anomalies within China via zonal and meridional heat transport. This is known as the ＂atmospheric-bridge＂, where the energy anomaly within the tropical Pacific transfers to the mid-high latitude in the northern Pacific through Hadley cells and Rossby waves, and to the western Pacific-eastern Indian Ocean through Walker circulation. This research also discusses the special air-sea boundary processes during the ENSO events in the tropical Pacific, and indicates that the influence of the subsurface water of the tropical Pacific on the atmospheric circulation may be realized through the sea surface temperature anomalies of the mixed water, which contact the atmosphere and transfer the anomalous heat and moisture to the atmosphere directly. Moreover, the reason for the heavy flood within the Changjiang River during the summer of 1998 is reviewed in this paper.

Evaluation model for freeway incident management system

In order to evaluate the general situation and find special problems of the freeway incident management system, an evaluation model is proposed. First, the expert appraisal approach is used to select the primary evaluation index. As a result, 81 indices and the hierarchical structures of the index such as the object layer, the sub-object layer, the criterion layer and the index layer are determined. Then, based on the fuzzy characteristics of each index layer, the analytical hierarchy process（AHP）and the fuzzy comprehensive evaluation are applied to generate the weight and the satisfaction of the index and the criterion layers. When analyzing the relationship between the sub-object layer and the object layer, it is easy to find that the number of sub-objects is too large and sub-objects are significantly redundant. The partial least square （PLS） is proposed to solve the problems. Finally, an application example, whose result has already been accepted and employed as the indication of a new project in improving incident management, is introduced and the result verifies the feasibility and efficiency of the model.

Some Interesting Features for External Region of Spherical Symmetric Mass in New Theory of Gravitation VGM

This paper briefly discusses some interesting features for the external region of the spherical symmetric mass in the new theory of gravitation VGM, i.e. the theory of gravitation by considering the vector graviton field and the metric field, such as pseudo-singularity, curvature tensor, static limit, event horizon, and the radial motion of a particle. All these features are different from the corresponding features obtained from general relativity.

The Kelvin Wave Processes in the Equatorial Indian Ocean during the 2006-2008 IOD Events

The present study investigates the role of Kelvin wave propagations along the equatorial Indian Ocean during the 2006-2008 Indian Ocean Dipole(IOD).The 2006 IOD lasted for seven months,developing in May and reaching its peak in December,while the 2007 and 2008 IODs were short-lived events,beginning in early May and ending abruptly in September,with much weaker amplitudes.Associated with the above IODs,the impulses of the sea surface height(SSH) anomalies reflect the forcing from an intraseasonal time scale,which was important to the evolution of IODs in 2007 and 2008.At the thermocline depth,dominated by the propagation of Kelvin waves,the warming/cooling temperature signals could reach the surface at a particular time.When the force is strong and the local thermocline condition is favorable,the incoming Kelvin waves dramatically impact the sea surface temperature(SST) in the eastern equatorial Indian Ocean.In July 2007 and late July 2008,the downwelling Kelvin waves,triggered by the Madden-Julian Oscillation(MJO) in the eastern and central equatorial Indian Ocean,suppressed the thermocline in the Sumatra and the Java coast and terminated the IOD,which made those events short-lived and no longer persist into the boreal fall season as the canonical IOD does.

Urban Boundary-Layer Stability and Turbulent Exchange during Consecutive Episodes of Particle Air Pollution in Beijing,China

Based on measurements at the Beijing 325-m Meteorological Tower,this study reports an analysis of atmospheric stability conditions and turbulent exchange during consecutive episodes of particle air pollution in Beijing(China),primarily due to haze and dust events(15–30 April 2012).Of particular interest were relevant vertical variations within the lower urban boundary layer(UBL).First,the haze and dust events were characterized by different atmospheric conditions,as quite low wind speed and high humidity are typically observed during haze events.In addition,for the description of stability conditions,the bulk Richardson number(RiB) was calculated for three different height intervals: 8–47,47–140,and 140–280 m.The values of RiB indicated an apparent increase in the occurrence frequency of stably-stratified air layers in the upper height interval—for the 140–280-m height interval,positive values of RiB occurred for about 85% of the time.The downward turbulent exchange of sensible heat was observed at 280 m for the full diurnal cycle,which,by contrast,was rarely seen at 140 m during daytime.These results reinforce the importance of implementing high-resolution UBL profile observations and addressing issues related to stably-stratified flows.

Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.

Relationship between the rock mass deformation and places of occurrence of seismological events

Static effort of rock mass very rarely causes of rock burst in polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts will be shown.

Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Ni o Events

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.

Reflection of Typhoon Morakot-The Challenge of Compound Disaster Simulation

Climate change has altered locally singletype disasters to large-scale compound disasters because of increasing intensity and frequency of extreme rainfall events.The compound disasters can combine small-scale floods,debris flows,shallow landslides,deep-seated landslides,and landslide lakes into a large-scale single disaster event.Although simulation models and evaluation tools are available for single-type disasters,no single model is well developed for compound disasters due to the difficulty of handling the interrelationship between two successive single-type disasters.This study proposes a structure for linking available single-type simulation models to evaluate compound disasters and provides a useful tool of decision making for warning and planning of disaster reduction.

Paleoearthquake Studies along the Nalinlaka Fault of the Late Pleistocene in Lhasa,Tibet

As the most import fault of the Late Pleistocene in the Lhasa area,the Nalinlaka fault is a left-lateral thrust fault,striking NWW,dipping SSW with a high dip angle,and extending over 33km.According to studies on the latest strata on the Nalinlaka fault zone,this fault zone has been obviously active since the Late Pleistocene and the movement left behind some geomorphologic phenomena on the earth's surface,especially at the sites of the gully west of Cijiaolin and around Xiecun village.For example,some rivers,ridges and terraces are displaced,forming beheaded gullies and fault escarps.The horizontal displacements since the Late Pleistocene at the above two places are 54m ～ 87m,20m ～ 67m,respectively.Based on studies on the 4 trenches along the fault using the progressive constraining method,we conclude that there might have been 5 paleoearthquake events along the Nalinlaka fault since 70ka B.P.,the ages of each paleoearthquake are 68.53,54.40,< 41.23,21.96,9.86ka B.P.,and the average recurrence interval is 14.67ka.Because of the limits of trenches and earthquake events exposed by each trench,no single trench completely revealed all 5 events.There may therefore be some errors in determining the upper and lower limits of some events in this article.

Coral Reef Recovery Status in South Andaman Islands after the Bleaching Event 2010

The Andaman and Nicobar Islands are one of the Union Territories of India, located in the eastern part of the Bay of Bengal. In 2010 summer, the increment in sea surface water temperature （up to 34℃） resulted in the bleaching of about 74% to 77% of corals in the South Andaman. During this event, coral species such as Acropora cerealis, A. humilis, Montipora sp., Favia paIlida, Diploastrea sp., Goniopora sp. Fungia concinna, Gardineroseries sp., Porites sp., Favites abdita and Lobophyllia robusta were severely affected. This study is to assess the recovery status of the reef ecosystem by estimating the percentage of Live Coral cover, Bleached coral cover, Dead coral with algae, Rubble, Sandy fiat, Algal assemblage and other associated organisms, The sedimentation rate （mg cm^-2 d^-1） and coral coverage （%） were assessed during this study period. The average sedimentation rate was ranged between 0.27 and 0.89 mg cm^-2 d^1. The observed post bleaching recovery of coral cover was 21.1% at Port Blair Bay and 13.29% at Havelock Island. The mortality rate of coral cover due to this bleaching was estimated as 2.05% at Port Blair Bay and 9.82% at Havelock Island. Once the sea water temperature resumed back to the normal condition, most of the corals were found recovered.

Discovery of the Surface Rupture Zone on the South of Helishan in Gaotai,Gansu Province

According to a new investigation in the northern Hexi corridor,the remains of two surface rupture zones were discovered on the southern margin fault of the Helishan. One rupture has a length of approximately 7km and the other 10km. The two surface rupture zones might have been produced by the latest earthquake event. On the surface rupture is continuous scarp and free face caused by the rupture. The scarp is about 1 ～ 1. 5m high and on some sites,nearly up to 2m. According to the OSL results,the latest T1 terrace and higher flood plain forming in 3000a B. P. are dislocated by the fault. The above reveals the rupture age to be later than the T1 terrace. However,in the historical data and earthquake catalogue,we didn't find related information about the fault and surface rupture in this area. The 180 A. D. Biaoshi M8. 0 earthquake and the 756 A. D. Zhangye-Jiuquan M7. 0 earthquake are documented in historical data. It is inferred by textual research that the two earthquakes are related to the northern marginal fault of Yumushan in the south of the basin. Due to a lack of reliable evidence,there are still many arguments on this inferred conclusion. Thus we hold that the two surface rupture zones were produced by one of the two large earthquakes or other unrecorded historical event. The research on the activity and surface rupture of this fault can offer valuable information for the tectonic study and strong earthquake risk estimates of this region in the future.

User-Level Sentiment Evolution Analysis in Microblog

People's attitudes towards public events or products may change overtime,rather than staying on the same state.Understanding how sentiments change overtime is an interesting and important problem with many applications.Given a certain public event or product,a user's sentiments expressed in microblog stream can be regarded as a vector.In this paper,we define a novel problem of sentiment evolution analysis,and develop a simple yet effective method to detect sentiment evolution in user-level for public events.We firstly propose a multidimensional sentiment model with hierarchical structure to model user's complicate sentiments.Based on this model,we use FP-growth tree algorithm to mine frequent sentiment patterns and perform sentiment evolution analysis by Kullback-Leibler divergence.Moreover,we develop an improve Affinity Propagation algorithm to detect why people change their sentiments.Experimental evaluations on real data sets show that sentiment evolution could be implemented effectively using our method proposed in this article.

Clustered trajectories anonymity in wireless sensor networks

This paper proposes a clustered trajectories anonymity scheme （CTA） that enhances the kano nymity scheme to provide the intended level of source location privacy in mobile event monitoring when a global attacker is assumed. CTA applies isomorphic property of rotation to create traces of the fake sources distributions which are similar to those of the real sources. Thus anonymity of each trajectory and that of the clustered is achieved. In addition, location kdiversity is achieved by dis tributing fake sources around the base station. To reduce the time delay, tree rooted at the base sta tion is constructed to overlap part of the beacon interval of the nodes in the hierarchy. Both the ana lytical analysis and the simulation results prove that proved energy overhead and time delay. our scheme provides perfect anonymity with improved energy overhead and time delay.

Investigation on very large scale motions(VLSMs) and their influence in a dust storm

Based on the real-time synchronous measurements of the wind velocity,temperature,the PM10 concentration at 16 m and 47 m during a dust storm event,in which Reynolds number Re exceeds 6×106,this study reveals the existence of the very large scale motions(VLSMs) during the stable stage both in the stream velocity and the temperature field at the two heights,whose streamwise scales reach up to 10 times the thickness of the boundary layer.The streamwise velocity and the PM10 concentration display a similar frequency corresponding to the peaks of their energy spectra,which implies that the VLSMs of streamwise flow have a significant role in dust transportation.In contrast,the salient deviations of the PM10 concentration at 47 m from the Gaussian distribution are revealed,which means that 47 m is not in the dust transportation layer,but is a region where the dust transportation layer and the outer flow intersect each other.Analysis demonstrates that the energy spectra of the PM10 concentrations at 16 m and 47 m display the "-1" scaling law feature,which has the same frequency range(0.001-0.1 Hz) as that of the wind velocity.This provides a new paradigm for the existence of the self-similarity scaling region in turbulent flow.

Incident-based traffic congestion control strategy

Traffic incident happens frequently in urban traffic network and it affects normal operation of traffic system seriously so that study on incident-based congestion control strategies is very important. This study addresses the problem of the temporary vehicle movement bans design under incident-based traffic congestion situation. A bi-level programming model is proposed to formulate this problem. The upper level problem is to minimize the total travel cost in the view of traffic management agencies, and the lower level problem is to present travelers’ dynamic route choice behavior under temporary vehicle movement bans using the simulation of cell transmission model, then a genetic algorithm is employed to solve the proposed bi-level programming model. Computational results show that the temporary vehicle movement bans measure is able to alleviate the traffic network incident-based congestion effectively and improve system performance of traffic network.

Responses of zonal wind at -40°N to stratospheric sudden warming events in the stratosphere, mesosphere and lower thermosphere

Based on the data at^40°N at different longitudes during different stratospheric sudden warming(SSW)events,the responses of zonal winds in the stratosphere,mesosphere and lower thermosphere to SSWs are studied in this paper.The variations of zonal wind over Langfang,China(39.4°N,116.7°E)by MF radar and the modern era retrospective-analysis for research and applications(MERRA)wind data during 2010 and 2013 SSW and over Fort Collins,USA(41°N,105°W)by lidar and MERRA wind data during 2009 SSW are compared.Results show that the zonal wind at^40°N indeed respond to the SSWs while different specifics are found in different SSW events or at different locations.The zonal wind has significant anomalies during the SSWs.Over Langfang,before the onset of 2010 and 2013 SSW,the zonal wind reverses from eastward to westward below about 60–70 km and accelerates above this region,while westward wind prevails from 30 to 100 km after the onset of2010 SSW,and westward wind prevails in 30–60 and 85–100 km and eastward wind prevails in 60–85 km after the onset of2013 SSW.Over Fort Collins during 2009 SSW,eastward wind reverses to westward in 20–30 km before the onset while westward wind prevails in 20–30 and 60–97 km and eastward wind prevails in 30–60 and in 97–100 km after the onset.Moreover,simulations by the specified dynamics version of the whole atmosphere community climate model(SD-WACCM)are taken to explain different responding specifics of zonal wind to SSW events.It is found that the modulation of planetary wave(PW)plays the main role.Different phases of PWs would lead to the different zonal wind along with longitudes and the different amplitudes and phases in different SSW events can lead to the different zonal wind responses.