Atmospheric Pressure Variations Research Articles

Manifestation of fault zones in geophysical fields

Geophysical fields influenced by tectonics faults were observed, and instrumental observation results are analysed in the article. It is shown that fault zones are characterized by geophysical fields that are more variable than those in midmost segments of crustal blocks, more intense responses to weak external impacts such as lunar and solar tides and atmospheric pressure variations, and intensive relaxation. Transformation of energy between geophysical fields varying in origin takes place mainly in the fault zones.

Affection Laws of Atmospheric Pressure to Gas Emission at Fully Mechanized Working Face

Gas emission is affected by many factors. Effects of atmospheric pressure on coal mine gas emission have become a rising concern. Basing on the gas emission at Y485 fully mechanized working face of Tangshan mine and atmospheric pressure, the paper had carried out online monitoring with sensors for 20 days continuously. Calculating the average values of atmospheric pressure and the expectation values of return air gas concentration of each hour on every monitoring date according to monitoring data, affection laws of atmospheric pressure to gas emission at fully mechanized working face were studied combining the weather and temperature of monitoring dates. It pointed out that the atmospheric pressure declines along with the rising of temperature and the gas emission at fully mechanized working face could be restrained if the atmospheric pressure rises, otherwise it could be promoted to release, the affection of variation of atmospheric pressure to gas emission was 0.0575%/hPa on cloudy day, and was 0.0446%/hPa on sunny day, and it was predicted that the peak time of gas emission at fully mechanized working face was from 12 o’clock to 16 o’clock according to the data processing results.

Atmospheric pressure variations at extratropical latitudes associated with Forbush decreases of galactic cosmic rays

Changes of troposphere pressure associated with short-time variations of galactic cosmic rays (GCRs) taking place in the Northern hemisphere’s cold months (October–March) were analyzed for the period 1980–2006, NCEP/NCAR reanalysis data being used. Noticeable pressure variations during Forbush decreases of GCRs were revealed at extratropical latitudes of both hemispheres. The maxima of pressure increase were observed on the 3rd–4th days after the event onsets over Northern Europe and the European part of Russia in the Northern hemisphere, as well as on the 4th–5th days over the eastern part of the South Atlantic opposite Queen Maud Land and over the d’Urville Sea in the Southern Ocean. According to the weather chart analysis, the observed pressure growth, as a rule, results from the weakening of cyclones and intensification of anticyclone development in these areas. The presented results suggest that cosmic ray variations may influence the evolution of extratropical baric systems and play an important role in solar-terrestrial relationships.

The Effect of Atmospheric Temperature and Pressure on the Occurrence of Acute Myocardial Infarction in Kaunas

OBJECTIVE. The aim of the study was to evaluate the impact of meteorological variables (atmospheric temperature and pressure) on the daily occurrence of acute myocardial infarction (AMI). MATERIAL AND METHODS. The study used the daily values of atmospheric temperature and pressure in 2000-2007. The meteorological data were obtained from the Lithuanian Hydrometeorological Service for Kaunas. The relative risks of event occurrence were computed for 5°C atmospheric temperature and for 10-hPa atmospheric pressure variations by means of the Poisson regression model. RESULTS. The occurrence of AMI and atmospheric temperature showed an inverse linear relationship, while the occurrence of AMI and atmospheric pressure, a positive linear relationship. Among the youngest subjects (25-44 years old), no relationships were detected. Contrary, among the subjects aged 45-64 years and those aged 65 years and older, the occurrence of AMI significantly decreased with higher temperature (P=0.001 and P=0.002, respectively). A decrease in atmospheric temperature by 10ºC reduced the risk of AMI by 8.7% in the age groups of 45-64 and 65 years and older and by 19% in the age group of 25 years and older. Among the first AMI cases, the risk increased by 7.5% in the age group of 45-64-year olds and by 6.4% in the age group of 25-64-year olds. The relationship between atmospheric temperature and pressure, and AMI occurrence was found to be linear but inverse. An increase in atmospheric pressure by 10 hPa resulted in an increase in risk by 4% among the subjects aged 65 years and more and by 3% among the subjects aged 25 years and more. CONCLUSIONS. Atmospheric temperature and pressure variations had the greatest effect on middle-aged and aging subjects (starting from 45 years). At younger age, the effect of such factors on the AMI risk was considerably lower.

Intratympanic Hemorrhage and Concussion in a Football Offensive Lineman

BackgroundA 26-year-old arena football lineman participating in a “bull in the ring” blocking and tackling drill was blindsided by an opposing teammate. He sustained a direct helmet-to-helmet blow to the right temporal area. ObjectivesThis case describes a unique mechanism of ear barotrauma (intratympanic hemorrhage) and concussion caused by helmet-to-helmet contact in American football. Case ReportInitial sideline evaluation revealed mild headache, confusion, dizziness, photophobia, and tinnitus, all consistent with a concussion diagnosis. Physical examination revealed a large postauricular contusion over the right mastoid process and diffuse right intratympanic hemorrhage on examination. No hemotympanum or effusion of the middle ear was noted. Abnormalities were seen on vestibular testing and visual accommodation and convergence testing. Computed tomography and magnetic resonance imaging were performed with attention to the temporal bones and were normal. Neuropsychological testing was abnormal compared to baseline. Audiology testing was within normal limits. Diagnosis was intratympanic hemorrhage secondary to barotrauma caused by helmet-to-helmet contact, with mastoid contusion and season-ending concussion. ConclusionsThe tympanic membrane (TM) is a highly vascular membrane that is very sensitive to variations of atmospheric pressure. Overpressure can enter the external auditory canal, stretching and displacing the TM medially and causing injury to the tympanic membrane secondary to barotrauma. This concussed football player was never able to return to play due to his postconcussive symptoms. He had no residual hearing or ear problems.

Oceanographic response to the passage of hurricanes in Belle Bay, Newfoundland

This study describes the changes in the sea surface elevation, temperature, and current pattern in Belle Bay, a side basin in a broad fjord on the south coast of Newfoundland, as a response to the passage of atmospheric instabilities. Between 11 July and 15 October 2011, Belle Bay experienced the passage of an oceanic storm (July), the hurricanes Katia and Maria (September), and hurricane Ophelia (October). In spite of the large atmospheric pressure variations, wind seems to be the main mechanism driving the sharp fluctuations in temperature and bottom currents. The response of Belle Bay to wind forcing resulted in a combination of barotropic and baroclinic processes. The barotropic response was modulated by a topographic effect, where the sea level elevation was higher near bathymetric constriction zones. The baroclinic response consisted in a deepening of the thermocline in a range of 30–40 m, evidenced by a significant increase in the temperature.

Solar diurnal anisotropy measured using muons in GRAPES-3 experiment in 2006

The GRAPES-3 experiment at Ooty contains a large-area (560 m2) tracking muon detector. This detector consists of 16 modules, each 35 m2 in area, that are grouped into four supermodules of 140 m2 each. The threshold energy of muons is sec(θ) GeV along a direction with zenith angle θ and the angular resolution of the muon detector is 6°. Typically, it records ~4×109 muons every day. The muon detector has been operating uninterruptedly since 2001, thus providing a high statistics record of the cosmic ray flux as a function of time over one decade. However, prior to using these data, the muon rate has to be corrected for two important atmospheric effects, namely, variations in atmospheric pressure and temperature. Because of the near equatorial location of Ooty (11.4°N), the seasonal variations in the atmospheric temperature are relatively small and shall be ignored here. Due to proximity to the equator, the pressure changes at Ooty display a dominant 12 h periodic behaviour in addition to other seasonal changes. Here, we discuss various aspects of a novel method for accurate pressure measurement and subsequent corrections applied to the GRAPES-3 muon data to correct these pressure-induced variations. The pressure-corrected muon data are used to measure the profile of the solar diurnal anisotropy during 2006. The data, when divided into four segments, display significant variation both in the amplitude (~45%) and phase (~42 m) of the solar diurnal anisotropy during 2006, which was a period of relatively low solar activity.

Non-Barotraumatic Tooth Fracture During Scuba Diving

When dental pain or tooth fracture occurs during diving, variations in atmospheric pressure are usually considered as etiology. We present a case of a military diver referred for dental pain which appeared during diving. Diagnoses suggested by the diving medical specialist were barodontalgia and dental barotrauma. The dental exam, however, highlighted a tooth fracture due to the in-diving use of an inappropriate mouth regulator which yielded excessive occlusal pressure on a tooth with pre-existing extensive dental restoration. This case highlights the importance of the use of an adapted mouthpiece by divers, and the need for awareness of physicians and dentists who treat divers of the implications of scuba diving on dental and oral medicine.

Global dust storm signal in the meteorological excitation of Mars' rotation

AbstractThe meteorological excitation of Mars' rotation refers to the change of Mars' orientation parameters caused by meteorological processes, e.g., that portion due to variations of atmospheric circulation and surface pressure, and a cryospheric part due to the variable Martian polar ice caps associated with the CO2 sublimation/condensation effects. Global dust storms (GDSs) are unique meteorological events on Mars that cause changes in surface pressure, polar caps extent, and circulation patterns on a global scale, which in turn alter Mars' rotation under the conservation of Mars' total angular momentum. In this paper, the GDS signal in the meteorological excitation of Mars' rotation is investigated on seasonal, diurnal, and semidiurnal time scales, based on the Martian Climate Database. On seasonal scales, the cryospheric excitation plays a less important role in general, due to its location at high latitudes, than its atmospheric counterpart. The GDS brings (−3%, +15%) changes in the amplitude of annual polar motion and length‐of‐day (LOD) variation and (+22%, −34%) changes in the amplitude of semiannual polar motion and LOD variation. On diurnal and semidiurnal scales, the cryospheric excitation can be fully neglected in comparison to its atmospheric counterpart. A significant GDS signal is found with respect to the diurnal polar motion and semidiurnal LOD excitation variation, because of strong atmospheric tides arising from GDS effects. The amplitude increases in diurnal polar motion and semidiurnal LOD variation during some periods of the Martian year may reach 3–5 times as large as those during the same stage in a typical Martian year.

Influence de la pression atmosphérique et de ses variations sur la rupture prématurée des membranes

In popular belief, a higher rate of premature rupture of membranes (PROM) might be associated with atmospheric pressure (AP) variations. Results of past studies are contradictory. We aimed to assess whether or not AP values influence the rate of PROM. We performed a retrospective longitudinal study of women admitted for PROM from January 1st, 2009 to December 3rd, 2009. AP values for 2009 were obtained at the local meteorological station. AP values (average, minimum and maximum) and its variations did not influence the rate of PROM for 341 patients included in the study, as well as in the group of 187 patients with a negative result of vaginal swab or amniotic fluid sample. After exclusion of premature PROM, mean AP variation the days before PROM was higher than AP variations of the days without PROM (6.3hPa IC95% [5.65-7.00] vs. 5.2 IC95% [4.70-5.79], P=0.029). No higher rate of occurrence of PROM was noticed during the days with low AP (AP less than average AP of the year equal to 1009hPa or AP less than normal AP equal to 1013.2hPa) or during the days with a high variability (maximal AP-minimal AP greater than 5hPa). Our data did not support the hypothesis that AP influence the rate PROM.

Uniformity and stability of the CMS RPC detector at the LHC

The Resistive Plate Chambers (RPCs) are employed in the CMS experiment at the LHC as dedicated trigger system both in the barrel and in the endcap. This note presents results of the RPC detector uniformity and stability during the 2011 data taking period, and preliminary results obtained with 2012 data. The detector uniformity has been ensured with a dedicated High Voltage scan with LHC collisions, in order to determine the optimal operating working voltage of each individual RPC chamber installed in CMS. Emphasis is given on the procedures and results of the High Voltage calibration. Moreover, an increased detector stability has been obtained by automatically taking into account temperature and atmospheric pressure variations in the CMS cavern.

Optimization of Ventilating Energy Distribution for Controlling Coal Spontaneous Combustion of Sealed Panel in Underground Coal Mines

In underground coal mines, the energy difference from sealed fire area to general mine atmosphere and variations in atmospheric pressure cause leakage, which can affect the stable status of sealed fire area even lead to reburning. In this study, a quantitative analysis method was presented to optimize ventilating energy distribution, which coupled the atmospheric pressure fluctuation. The method was applied to the sealed fire area management in a high gas emission coal mine. Based on analysis results, the “one into and four outs” system, four fire dams in air-outflow condition with continuous nitrogen injection, was realized stably by setting up adjustable ventilation facilities reasonably. After the ventilating energy distribution was optimized, oxygen and carbonic oxide concentration of sealed fire area declined remarkably with less than 5% and 10ppm respectively. The state was maintained one month, which established a basis for the unsealing of sealed fire area.

The first results of studies of temporary variations in soil-radon activity of faults in Western Pribaikalie

Radon concentrations in soil air are variable depending on factors that are considered external (planetary) and internal (geodynamic) relative to the Earth. In active fault zones, variations of gas emanations are most intense. A permanent monitoring station was established near Tyrgan settlement in Western Pribaikalie to study temporal variations of soil radon concentration, Q, in the faults of the Baikal rift, East Siberia. This station is located in the zone of the Primorsky normal fault that is the largest in the region. The station is equipped with radon radiometer PPA01M03 that records Q values every 85 minutes and also monitors a number of meteorological parameters, including atmospheric pressure, humidity, and air temperature. We analysed records of two measurement sessions (148 and 66 days) covering a part of the year during which field measurement of Q are possible in the cold climate conditions of the area under study. According to the available monitoring data, variations of radon concentrations in the Primorsky fault zone may vary by more than one order of magnitude through a springsummerautumn period, and such variations are oscillatory. Significant changes of permeability in time occur due to intensive changes in the state of stresses of the rock massives under the impacts of the planetary and geodynamic factors. The influence of the first group of factors, i.e. planetary ones, is manifested by synchronous oscillations of radon concentrations and atmospheric pressure, which phases of occurrence are opposed. Domination of daily and fourday periods gives evidence that the state of stresses of the rock massives is impacted by the lunar tides and cyclonic phenomena associated with the interaction between the Earth and the Sun. The influence of the second group of factors, i.e. geodynamic ones, is suggested by an evident relation between radon emanations and seismic events, including the catastrophic earthquake in Japan (March 11, 2011, M=9.0). Tectonophysics The external and internal factors are acting together, but their roles are different with regard to variations of radon concentrations in different periods of time. In the monitoring periods, radon emanation variations were mainly controlled by the planetary factors. Radon exhalation increases and decreases according to periodic variations in atmospheric pressure, which, in additional to ‘pumping’ effects, may lead to opening/closure of pores and cracks in the rocks. While external pressures are reduced, internal stresses are released by relatively weak earthquakes. The guiding influence of atmospheric pressure on the yield of radon is disturbed when internal stresses are in excess of a certain level due to intensive movements along faults in the Baikal rift or displacements of plates in neighbouring active zones (for example, due to the strongest earthquake in Japan). In such relatively short periods of time, when seismic activity is increased, the influence of tectonic stresses on permeability of rocks and radon emanations becomes dominant. Based on our analysis of the measurements of soil radon concentrations obtained on the local site in the Primorsky fault zone through the monitoring period, it became possible, for the first time for Pribaikalie, to reveal and theoretically model the principal specific features of variation of soil radon concentrations, Q, in time and the dependence of such variations on the external and internal factors. Prospects of these studies are related to installation of a network of monitoring stations in the territory of the Baikal rift and assurance of longterm monitoring sessions.

Metrological Analysis of Geopotential Gravity Field for Harbor Waterside Management and Water Quality Control

Sea level oscillations are the superposition of many contributions. In particular, tide is a sea level up-down water motion basically depending on three different phenomena: the Earth-Moon-Sun gravitational relationship, the water surface fluid reaction to atmospheric meteorological dynamic, and the Newtonian vertical adjustment of the sea surface due to atmospheric pressure variations. The first tide component (astrotide) is periodic and well known in all points of the Earth surface; the second one is directly related to the meteorological phenomenon, and then it is foreseeable; the Newtonian component, on the contrary, is not readily predictable by a general hydrostatic law, because theJfactor that represents the Newtonian transfer (from the atmospheric weight to the consequent sea level) is variable in each harbor area. The analysis of the gravity field permits to forecast the sea level variation due to meteorological tide events, and its metrological analysis highlights a compensation in the inverse hydrobarometric factor to be taken into account to correctly compensate atmospheric pressure variations in semibinding basins. This phenomenon has several consequences in Harbor Waterside management and in water quality control as shown by the reported case studies and introduces a new reference parameter: the so-called Water 1000.

G1101 風洞実験用空気軸受型3分力ロードセルの開発研究(GS11 物体まわり流)

An air suspended load cell, which is available to measure steady aerodynamic forces on the spinning golf ball in the wind tunnel flow, has been developing during these five years. The characteristic to measure two components of forces as drag and side ones had already been accomplished with sufficient accuracy. However, the performances of the lift force direction had not been achieved by the influences of atmospheric pressure changes. The sufficient accuracy has accomplished, in this study, mainly by two improvements of the light-weight of ball supporting unit and the cancellation mechanism of atmospheric pressure variations. The lift force on highly spinning golf ball in the wind tunnel flow are measured and compared with the results of gauge type load cell.

A NUMERICAL STUDY ON LONG-WAVE GENERATION DUE TO ATMOSPHERIC-PRESSURE VARIATION

The generation and propagation of long waves due to atmospheric-pressure variation have been numerically simulated, where the atmospheric-pressure waves are assumed to travel in the eastern direction over East Chine Sea. The wave height of long waves is larger as the moving velocity of the recovery point of water surface pressed by the atmospheric pressure is close to the long-wave celerity. Before attenuation of the harbor oscillation in Urauchi Bay, Kamikoshiki Island, the incidence of long waves can continue because of the oscillation system generated between the main island of Kyushu and Okinawa Trough. The pressure profiles of atmospheric-pressure waves supposed to have concerned the large harbor oscillation in Urauchi Bay from 2009 to 2010 are classified into four patterns based on the Grid Point Value pressure data. The incident long waves causing the largest harbor oscillation in Urauchi Bay on Feb. 25, 2009 has been simulated with the estimated pressure-profile pattern, such that the largest harbor oscillation in Urauchi Bay should occur due to the atmospheric-pressure waves.

Performance of the Gas Gain Monitoring system of the CMS RPC muon detector and effective working point fine tuning

The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detectorin the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination ofthe stability in the working point conditions due to gas mixture changes in the closed loop recirculationsystem. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms.

Enhanced ring lasers: a new measurement tool for Earth sciences

We report the progress in the technology of fabrication of large ring lasers that has resulted in an increase in instrumental rotation sensitivity by as much as a factor of 3, to δΩ = 1.2 × 10-11 rad s-1 Hz-1/2, which makes the domain of changes in the angular velocity of Earth's rotation, ΔΩ/Ω ≈ 10-9, accessible to a local rotation sensor. New studies show that the largest contribution to the observed deviation in sensor performance with respect to the computed shot noise limit is caused by the micro-seismic background activity of the Earth. Our efforts have been concentrated on the improvement of sensor stability, including correction of drift effects, which are caused by the aging of the laser gas, fixing scale factor instabilities induced by atmospheric pressure variations, and minimising the temperature variations resulting from corresponding adiabatic expansion and compression of the local air around the instrument. To achieve this, we have recently introduced a pressure-stabilising vessel with dimensions slightly larger than the ring laser apparatus, such that it encloses the entire structure. By monitoring the optical frequency in the ring laser cavity continuously and stabilising the scale factor in a closed loop system with the pressure-stabilising vessel, it has become possible to extend the range of sensor stability from the short term (1 — 3 days) to well into the mid-term regime (>40 days), and possibly even well beyond that. Once a sufficiently long timeseries of the ring laser data has been recorded, we will be able to define the range of temporal stability in more detail. The extension of the regime of stability gives access to geophysical signals at frequencies substantially lower than previously observable with ring lasers.

Titanium ball joint total ossicular replacement prosthesis – Experimental evaluation and midterm clinical results

During reconstruction of the ossicular chain, there is a need to address the forces and loads caused by the ambient atmospheric pressure variations and the resulting tympanic membrane movements. It is understood that when a rigid middle ear prosthesis is inserted the malleoincudal joint, a keyfactor in controlling pressure variations in the middle ear space is bypassed. In this paper we describe a modified total titanium ossicular replacement prosthesis with an innovative micro ball joint in the headplate which is designed to compensate for tympanic membrane movements caused by atmospheric pressure variations. The characteristics of this modified prosthesis were examined in temporal bone experiments and compared to the standard titanium total ossicular reconstruction prosthesis. Sound-induced stapes footplate movements were investigated by means of a Laser vibrometer and revealed no significant differences between the two prostheses in vitro. Intraoperatively, the insertion of the modified prosthesis required more delicate handling. The angle between the shaft and the headplate was variable and ranged from 60 to 90° as estimated by the surgeon. Twelve consecutive patients were eligible for clinical evaluation. The pure tone average (PTA) air-bone gap after a mean follow up period of 32 months was 18.8 dB. Furthermore, no extrusion, dislocation or other adverse events were observed. We conclude that the modified total ossicular replacement prosthesis with integrated micro ball joint yields similar volume velocities of the stapes footplate in the laboratory experiments compared to the standard rigid prosthesis. The audiological and morphological results are encouraging and show that the mobile prosthesis headplate adjusting to the level of the tympanic membrane is a further step in the development of a physiological middle ear implant.This article is part of a Special Issue entitled “MEMRO 2012”.

Online application for the barometric coefficient calculation of the NMDB stations

The primary processing of the neutron monitor data includes all the necessary actions and procedures that each cosmic ray station follows in order to provide the worldwide neutron monitor network with good quality data. One of the main corrections of the primary data is the pressure correction due to the barometric effect. The barometric effect induces variations to the measured data of the neutron monitors which are related to the variations of the local atmospheric pressure of the stations. This correction requires the definition of the barometric coefficient which is calculated experimentally. The accurate calculation of the coefficient is a prerequisite for the quality of the data. This paper presents the implementation of an online tool which calculates the barometric coefficient of a cosmic ray station, by taking advantage of the fact that most stations publish their data on the Neutron Monitor Data Base.