Atmospheric Pressure Variations Research Articles

A new method for determining air permeabilities of wood-based panels

In this study, a new apparatus for measuring the air permeability of wood-based panel specimens without using water displacement was developed with the aim of decreasing the influence of variation in atmospheric pressure on permeability measurement. Validation experiments were conducted using plywood, oriented strand board (OSB), particleboard, and medium-density fiberboard (MDF) panels and a control specimen sealed with an epoxy resin. The background (leakage) flow of the apparatus was evaluated based on the experimental results of the control specimen. A methodology for the determination of air permeability based on Darcy’s law for gases and the evaluated background flow rate was proposed. The results of the current study were compared with those obtained in a previous study, indicating that the new method provides valid measurements for wood-based panels with high and low air permeability. No significant influence of variation in atmospheric pressure on the experimental results was observed, suggesting that the proposed method is suitable for a long-term continuous experiment for evaluating a specimen with extremely low permeability

Response of sea level to tide, atmospheric pressure, wind forcing and river discharge in the Kitimat Fjord System

The response of sea level to tide, atmospheric pressure, wind forcing, and river discharge in the Kitimat Fjord System (KFS) is investigated by using observations from tide gauges and results from a high-resolution ocean circulation model. Tidal harmonic analysis of the observed hourly sea level at the head and mouth of Douglas Channel shows that the largest semidiurnal tide (M2) alone accounts for 79% of the total sea level variance, and the top four major tidal constituents (M2, S2, K1, and O1) account for 94% of the total variance. In addition, the amplitude of M2 increases slightly from 1.586 to 1.647 m between the mouth and the head. For the observed subtidal sea level, the local inverse barometer response due to the variation of atmospheric pressure accounts for 59% of the variance. The variation of subtidal sea level difference between the mouth and the head of Douglas Channel is observable and can be largely attributed to the along-channel wind (54%) with an additional 13% of the variation due to the daily-averaged and seasonal-cumulative river discharges.A fjord-shelf three-dimensional ocean circulation model for KFS is developed to simulate the sea level variability. The model performance in simulating the sea level is assessed by comparing model results with observed harmonic constituents of ~70 tidal stations inside the model domain and time series recorded at the two tide gauges of KFS. The modelled tides are in good agreement with observations with a domain-averaged root-mean-square error estimate of ~0.04 m for M2. For the subtidal sea level, the model is able to capture the observed synoptic variations. Further analysis suggests that the underestimates of subtidal sea level in the ocean circulation model are mainly due to the weaker-than-observed wind forcing taken from the atmospheric model especially during the peak of strong down-fjord katabatic wind events.

Simulation of Propagation of Acoustic-Gravity Waves Generated by Tropospheric Front Instabilities into the Upper Atmosphere

A numerical model of the propagation of acoustic-gravity waves excited by pressure fluctuations on the Earth’s surface is developed. Propagation of acoustic-gravity waves generated by instabilities of tropospheric fronts into the upper atmosphere is simulated. The experimental data on atmospheric pressure variations during 2016 year registered on a net of four microbarographs located in the Moscow region are processed. A case of very significant pressure fluctuations (up to 30 times larger than the average level) is selected, which were caused by an atmospheric front arrival. Observed surface pressure field variations for this field were approximated and used as the lower boundary condition for simulating the vertical wave propagation. The numerical simulations showed that just after the boundary source activation, the infrasonic waves in the upper atmosphere may have amplitudes of perturbations of temperature up to 100 K, and horizontal velocity up to 60 m/s. Internal gravity waves come into the upper atmosphere later and far horizontally away from the wave source. The influence of the limited dimensions of the computational domain on the simulation results is investigated. The conditions at the horizontal boundaries of the computational domain, which allow the runaway of waves beyond the domain are proposed. The frequency spectrum of waves in the non-isothermal atmosphere is analyzed.

Towards understanding relationships between atmospheric pressure variations and long-period horizontal seismic data: a case study

SUMMARYVariations in atmospheric pressure have long been known to introduce noise in long-period (>10 s) seismic records. This noise can overwhelm signals of interest such as normal modes and surface waves. Generally, this noise is most pronounced on the horizontal components where it arises due to tilting of the seismometer in response to changes in atmospheric pressure. Several studies have suggested methodologies for correcting unwanted pressure-induced noise using collocated microbarograph records. However, how applicable these corrections are to varying geologic settings and installation types (e.g. vault versus post-hole) is unclear. Using coefficients obtained by solving for the residuals of these corrections, we can empirically determine the sensitivity of instruments in a specific location to the influences of pressure. To better understand how long-period, pressure-induced noise changes with time and emplacement, we examine horizontal seismic records along with barometric pressure at five different Global Seismographic Network stations, all with multiple broadband seismometers. We also analyse three Streckeisen STS-2 broadband seismometers, which are collocated with a microbarograph, at the Albuquerque Seismological Laboratory. We observe periods of high magnitude-squared-coherence (γ2-coherence; γ2 > 0.8) between the seismic and pressure signals which fluctuate through time, frequency, and even between seismic instruments in the same vault. These observations suggest that these tilt-generated signals are highly sensitive to very local (<10 m) site effects. However, we find that in cases where instruments are not located at a large depth (<100 m), the pressure-induced noise is polarized in a nearly constant direction that is consistent with local topographic features or the geometry of the vault. We also find that borehole instruments at a large depth (>100 m) appear to be unaffected by pressure-loading mechanisms outlined by Sorrells (1971) but possibly by Newtonian attraction. Correlating the induced-noise polarization direction with times of high coherence, we work to identify sensors that are ultimately limited by pressure-induced horizontal noise as well as period bands that can benefit from pressure corrections. We find that while the situation is complex, each sensor appears to have its own unique response to pressure. Our findings suggest that we can determine empirical relationships between pressure and induced tilt on a case by case basis.

Relative importance of surface air temperature and density to interannual variations in monthly surface atmospheric pressure

AbstractThe spatial inhomogeneity of air pressure drives the atmospheric circulation. The interannual variation of the pressure can be affected by both air temperature and density. The goal of this study is to identify, for the near‐surface air, whether the variation of the density or temperature is more important in the interannual variation of the pressure. The physical relation of the pressure (P) with density (D) and temperature (T), denoted as P = D ⋅ T for simplicity, is nonlinear. To be convenient for estimating the relative importance, a normalized linear regression is used to fit the relation, which is finally written as P = AD + BT. Tests show that the linear fitting is robust; it is perfect everywhere in the globe. Because of the normalizations, the D and T are in magnitude of 1, but can be positive or negative. Derivations and calculations indicate that the coefficients A and B are both positive. What they reflect are the partial correlations of the pressure with the D and T, which are both equal to 1 across the entire field. For the normalized fitting, the A and B can be used to estimate the contributions of the D and T to the variation of the pressure. The linear fitting method can provide quantitative results for the dominance. The original nonlinear relation, due to the special form for the issue, can be used to qualitatively deduce the dominance. Comparisons suggest that the results obtained from the linear fitting are consistent with those qualitatively reached from the nonlinear physical relation. The consistency is true, no matter what the relation is between the two influencing factors. Corresponding to the negative relation between the density and temperature, there are two patterns. One is that the pressure increases with density but decreases with temperature. In this case, density dominates the variation of pressure. The second is that the pressure increases with temperature but decreases with density, and thus temperature dominates the variation of pressure. The third pattern is for the positive relation between density and temperature. In this case, density and temperature both have positive contributions to the variation of pressure, and which of them is more important can further be assessed with the linear fitting method.

Atmospheric Manifestations of the Strong Earthquakes

Based on the analysis of data from the Geophysical Observatory “Mikhnevo” and the Center for Geophysical Monitoring of Moscow of the Institute of Geosphere Dynamics of the Russian Academy of Sciences, the response of the atmospheric boundary layer to the strong earthquakes with magnitudes starting from ≥7 is considered. It is shown that the Tohoku earthquake (March 11, 2011, Japan) can be associated with the variations in atmospheric pressure with periods ranging from 8 to 11 h that emerged after this event, whereas a series of the strong earthquakes discussed in the work are accompanied by the variations in the atmospheric pressure with periods close to the singlets of the fundamental free oscillation of the Earth 0S2. Another effect after the earthquakes is the presence of the acoustic-gravity waves in the atmosphere with a period close to the Brunt-Vaisala period at large distances from the epicenter.

Pressure Effects on the SEIS‐InSight Instrument, Improvement of Seismic Records, and Characterization of Long Period Atmospheric Waves From Ground Displacements

AbstractMars atmospheric pressure variations induce ground displacements through elastic deformations. The various sensors of the InSight mission were designed in order to be able to understand and correct for these ground deformations induced by atmospheric effects. Particular efforts were made, on one hand, to avoid direct pressure and wind effects on the seismometer and, on the other hand, to have a high performance pressure sensor operating in the same frequency range as the seismometer. As a consequence of these technical achievements and the low background seismic noise of Mars, the InSight mission is opening a new science domain in which the ground displacements can be used to perform atmospheric science. This study presents an analysis of pressure and seismic signals and the relations between them. After a short description of the pressure and seismic sensors, we present an analysis of these signals as a function of local time at the InSight location. Then the coherent signals recorded by both pressure and seismic sensors are described and interpreted in terms of atmospheric signals and ground deformation processes. Two different methods to remove the pressure effects recorded by SEIS sensors are presented, and their efficiency is estimated and compared. These decorrelation methods allow the pressure generated noise to be reduced by a factor of 2 during the active day time period. Finally, an analysis of SEIS signals induced by gravity waves demonstrates the interest of ground displacement measurements to characterize their arrival azimuth.

Simulation of the mushroom cloud generated from a high-energy explosion using large-eddy simulation

We performed numerical simulations of a 20 kT heavy explosion to predict the rise and diffusion of mushroom cloud after the atmospheric pressure is recovered around the burst point. We proposed a new formulation of governing equations based on the anelastic approximation and density weighted variables to implement the atmospheric stratification by employing potential temperature to account for the effect of atmospheric pressure variation in altitude. To validate the simulation results, we chose similar explosive yield cases performed at the Nevada sites to compare the mushroom cloud height and diameter. Parametric studies were performed by varying the grid size and global subgrid-scale coefficients, Cs, to find the appropriate value that guarantees reliability of simulation results. Based on the optimal simulation results, the cooling process of mushroom cloud and the suppressed ascending air currents around tropopause were investigated.

What Pulsating H2 Emissions Suggest about the H2 Resource in the Sao Francisco Basin of Brazil

Proterozoic sedimentary basins very often emit natural hydrogen gas that may be a valuable part of a non-carbon energy infrastructure. Vents in the Sao Francisco Basin in Brazil release hydrogen to the atmosphere mainly during the daylight half of the day. Daily temperature and the regular daily tidal atmospheric pressure variations have been suggested as possible causes of the pulsing of H2 venting. Here, we analyze a ~550 m-diameter depression that is barren of vegetation and venting hydrogen mainly at its periphery. We show that daily temperature changes propagated only ~1/2 m into the subsurface and are thus too shallow to explain the H2 variations measured at 1-m depth. Pressure changes could propagate deeply enough, and at the depth at which the cyclic variations are measured hydrogen concentration will have the observed phase relationship to atmospheric pressure changes provided: (1) the pressure wave is terminated by geologic barriers at about 25% of its full potential penetration distance, and (2) the volume of gas in the vents is very small compared to the volume of gas tapped by the venting. These constraints suggest that there is a shallow gas reservoir above the water table under the ~550 m-diameter barren-of-vegetation depression. The 1D-analytical and finite-element calculations presented in this paper help define the hydrogen system and suggest the further steps needed to characterize its volume, hydrogen flux and resource potential.

Closed‐end capillary rise—An experimental study

AbstractThe spontaneous rise of Newtonian liquids in closed‐end capillaries is investigated with three different organics. Rise rate and equilibrium height are significantly reduced by a compression induced minor elevation in air pressure within the capillaries. We verify our earlier mathematical analysis quantifying viscous dissipation within air, and also show that the dynamic contact angle plays a material role. The relative importance of these varies with capillary dimensions. We also quantify the influence of atmospheric pressure variation and the temperature induced fluctuations in the rise height. A single parameter that relates static and dynamic contact angles is sufficient to match all of the data. This parameter is obtained from an open‐capillary experiment.

Vertical Propagation of Acoustic Gravity Waves from the Lower Atmosphere during a Solar Eclipse

This paper presents the results of the analysis of a numerical experiment on the generation of acoustic gravity waves (AGWs) in the lower atmosphere and their propagation into the upper atmosphere. The observed variations in atmospheric pressure during the passage of a solar eclipse on March 20, 2015, over Kaliningrad (54° N, 20° E) are considered the be a wave source. The calculation results showed that the passage of a solar eclipse is accompanied in the lower atmosphere by an increase in wave activity in the AGW range with periods of ~4–20 min. In the upper atmosphere, at altitudes of ~200 km, disturbances are formed due to the dissipation of AGWs coming from the lower atmosphere; these disturbances propagate with characteristic periods of ~50 min. The propagation direction of these disturbances was opposite to the propagation direction of the solar eclipse region along the Earth’s surface. The results of the numerical experiment are in qualitative agreement with the results of observations of ionospheric disturbances during the solar eclipse on March 20, 2015.

Effects and Correction of Atmospheric Pressure Loading Deformation on GNSS Reference Stations in Mainland China

Atmospheric pressure loading (APL) deformation is one component of nontectonic deformation for Global Navigation Satellite System (GNSS) time series and is a kind of deformation response caused by a redistribution of atmospheric pressure. In this paper, we present an atmospheric data processing strategy to compute the APL based on a spherical harmonic expansion of the global atmosphere pressure changes. We also provide a sample model to describe the relativity between the global atmosphere pressure changes and APL vertical deformation. The results show that the variation of air mass has a major impact on the north-eastern area of East China, the eastern area of North China, and Northeast China, and the vertical crustal displacement caused by the atmosphere changes in these regions can reach about 20 mm. The correction of APL for vertical time series of GNSS reference stations in different regions indicates that the arid area of the Northwest China, Northeast China, Central China, and North China are greatly affected by APL. While for the station located in Sichuan-Yunnan region, the amplitude and period change are small after correction of APL for vertical time series of GNSS reference stations, which reveals that the area is seriously affected by tectonic movement and water migration loading. The correlation between atmospheric pressure changes and crustal deformation is analyzed, which shows that APL has a serious impact on the north-eastern area of North China, the Northeast China, and the eastern area of Central China when the variations in atmospheric pressure in mainland China are the same. The research results of this paper will provide some reference value for the study of crustal structural deformation and the establishment of geodetic datum.

Search for Atmospheric Wave Signatures by Simultaneous Collocated Barometer and Gravimeter Measurements

A spatial distribution model for air density perturbations during the propagation of internal gravity waves (IGWs) is used to derive estimates for gravity perturbations generated by these waves. The estimates show that superconducting gravimeters are capable of detecting IGWs generated by any wave source in the lower atmosphere. Series of barometric and gravimetric measurements at Moxa, Germany (50.6° N, 11.6° E), for 2000–2018 are processed using digital filtering to search for pressure and gravity perturbations with time scales of ~10 min to ~10 h. The annual change in the atmospheric pressure variation with variation scales on the order of and less than 1 h shows a summer maximum, which disappears at higher scales. The summer maximum can be attributed to the effect of IGWs with periods on the order of and less than 1 h from convective clouds that occur in the summer half of the year. The annual change in the gravity variation shows maximums in winter and summer for all the variation scales under consideration. They can be explained by modulating the solar semidiurnal gravitational tide by a semiannual change in the perturbation of the Earth’s gravitational potential.

Measurement and Forecasting of Port Tide Hydrostatic Component in North Tyrrhenian Sea (Italy)

Starting from the end of the 90s not perodic and unpredictable variations in the depth of harbor waters were observed. Long period (from 24 hours to a few days) and wide amplitude are their main features. Experience showed that this phenomenon is a risk for harbor navigation and mooring. It may be a serious obstacle to waterside port activities. The first observation of the data does not link the super-highs and the super-dry tides to the meteorological dynamic of sea-atmosphere interaction (i.e. Storm Effect). More, the attempt to compensate for these sea depth fluctuations by means of the well-known offshore hydrobarometric inverse parameter (1 [cm] sea level variation for &#451 [hPa] atmospheric pressure variation) underestimates the amplitude of the phenomenon. In the first years of 2000, the Italian Ministry of Transport launched a national project for the definition of thee-amplitude and time of these tidal anomalous waves. The measure of harbors hydrobarometric inverse factors showed a much more intense value than the theoretical one (computed for the offshore). These amplification factors are characteristic of each harbor and can be double (in exceptional cases even more) than offshore. The delay between the arrival times of these tidal waves (induced phenomenon) respect to the time of arrival of the atmospheric pressure variation (inducing phenomenon) depends on 1) morphology of the port basin sea floor and 2) harbor and off-shre water dynamics relationship (first approximation). For these reasons the hydro barometric inverse parameter is not effectiveness computable but it can be determined statistically.

On the Problem of Taking into Account the Effect of Meteorological Factors on Large Precision Systems: A Case Study of the Baksan Large-Base Laser Interferometer

Variations in ambient temperature and atmospheric pressure coincide with the wave train of the lunar–solar tide in the diurnal and semidiurnal frequency ranges, where they have the greatest influence on deformation measurements by laser interferometers. Based on data from the Baksan laser interferometer of the Sternberg Astronomical Institute of Moscow University over a 15-year observation period, it is shown that the response of large measuring systems to these variations has a pronounced frequency dependence. Using the constructed mathematical model the problem of taking into account how meteorological factors influence measurements is solved in the frequency domain with the aid of images of deformation time series and meteorological factors, obtained by Fourier transform. A transient function is constructed in the form of the so-called aperiodic link, which takes into account the frequency dependence and delay of thermoelastic deformation of the measuring system on the variation in ambient temperature. The converted temperature and pressure images are subtracted from the deformation image using the corresponding transient functions. As a result, the new deformation image bears virtually no influence of meteorological factors; inverse transform yields a new deformation time series.

Atmospheric Pressure Variations Induced by the Tohoku Earthquake

The response of atmospheric pressure to the Tohoku earthquake on February 11, 2011 (magnitude M ~ 9), is analyzed using the results of instrumental observations made at the Mikhnevo Geophysical Observatory, Institute of Geosphere Dynamics, Russian Academy of Sciences (IDG RAS). It is shown that the earthquake gave rise to atmospheric pressure fluctuations with periods as long as 8.5, 9.4, 10, and 10.4 h. Waves in an isothermal atmosphere with a source at the earthquake epicenter are considered as a possible cause of excitation of these basic variations.

Fast feasibility assessment of water bodies free oscillations energy potential use

The author has developed an operational method of assessing the expediency of implementing innovative projects on the use of the hydropower potential of the natural oscillations of water in an uncertain hydrological conditions. It is determined that the total hydropower potential of Ukraine, in addition to natural runoff, are waves and currents, which are constantly offered innovations. It is shown that the capacities of the reservoirs determine their individual spectra, the construction of which is a time consuming study. Self-oscillations are excited by a single pulse external to the reservoir of power. Impulse external force acts Dolgoprudny wave is comparable with the natural oscillations of the reservoir frequency: periodic inlet-forming power of the Sun and moon; wind waves, which leads to f and Negev; the accumulation of water in one part of the reservoir, caused by the streams flowing into and flowing year or rainfall; abrupt variations in atmospheric pressure above the water surface or ice cover; seismic phenomena. Substantiates the connection between the external seal centrifugal force and the part of the fluctuations of the hydrometeorological characteristics of this sealing which is created by centrifugal force, and constructed a genetic method of long-term marine forecasts. The pond is seen as a generator of sasova waves and currents in an uncertain hydrological conditions. For the calculations applied the genetic method, the result of which is the construction of amplitude-frequency characteristics of oscillations of the pool, excited by an external force. Typical spectra level oscillations and currents of water bodies For decision making on the appropriateness of potential it is proposed to compare the calculated unit cost of electricity with the cost of energy produced by alternative methods. The characteristics of GES, which should be considered when assessing the feasibility of using the energy potential of natural oscillations of the reservoir.

Characterization of a local dust storm on Mars with REMS/MSL measurements and MARCI/MRO images

The REMS instrument on board the Curiosity rover has been collecting meteorological data from Gale crater on Mars since August 2012. A dust storm that developed north of Gale crater in sol 852 of the Mars Science Laboratory (MSL) mission spread above the location of the Curiosity rover during sols 853–855 (December 30, 2014 to January 1, 2015, areocentric solar longitude Ls 263°, MY32). The storm was observed by the MARCI imaging instrument on the Mars Reconnaissance Orbiter and its effects in the local meteorology were recorded in situ by the REMS instrument on MSL. Here we present a detailed report of the effects of the storm at Gale crater. Using MARCI images, we measured the size and altitude of the dust storm, which reached a size of 482,000 km2, attained an altitude of 19 km above the ground, and dispersed through the Gale crater and its surrounding area the next sol. The dispersion of the dust from the storm was roughly in agreement with the expected values of the winds on Ls 263° from climatological values in the Mars Climate Database (MCD). REMS data show that the storm produced the following effects when the dust arrived at Gale: (1) An increase in the daily amplitude of the atmospheric pressure variation (~15 ± 3 Pa) mainly through a reduction of the daily minimum pressure (~12 Pa) in the late afternoon hours. (2) A decrease of the UV signal (~30%). (3) An unexpected increase in the temperature of the air close to the surface (~14 ± 4 K) in the early afternoon (LT~14–15). (4) A cooling of the surface near noon (~6 ± 4.5 K). The warming of local air was contrary to previous observations of effects of dust storms on the Martian surface. This could be due to the vertical distribution of dust when the storm arrived at Gale crater, which was less vertically extended than in the previous sol. However, the data does not allow for a quantitative evaluation of this hypothesis. Although the storm could be observed from orbit only over one single sol above Gale crater its effects over the local meteorology lasted longer and dissipated in a time-scale of 3 sols.

Radon concentration in groundwater sources of the Baikal region (East Siberia, Russia)

In this study, we conduct a systematic study of groundwater radioactivity in the territories around Lake Baikal in Siberia, including Pribaikalie and Transbaikalia. The database includes more than 200 measurements of 222Rn from monitored water sources in the study region. We classify the groundwater sources in the Baikal region into seven groups (I–VII) that differ in radon concentration in space and time. The spatial distribution of water sources belonging to certain groups depend on geochemical and structural factors. In Transbaikalia, intrusive rocks with elevated contents of uranium are abundant. In Pribaikalie, many water sources are classified into Groups I and II (Q < 100 Bq/L). Group I includes groundwater with background concentrations, and Group II includes groundwater with anomalous concentrations of radon. Water sources belonging to elevated radon concentration Groups III to VI are considered as anomalies. Faulting is one of the main causes of radon anomalies as groundwater in the fault zones is enriched with 222Rn due to the increased permeability of rocks and rock crushing resulting from displacements of the fault walls.Monitoring of water sources in Pribaikalie shows that 222Rn concentrations vary also in time mainly within the range of values corresponding to a particular group. The oscillatory pattern of the temporal variations is clearly revealed by radon measurements conducted every two weeks and depends mainly on meteorological factors. Seasonal variations in air temperature and atmospheric pressure lead to changes in groundwater temperature, dilution of groundwater due to precipitation, freezing the top layer of soil, and other phenomena. As a result, the concentration regularly increases in winter and decreases in summer. In this study, seismic activity has not been revealed as significant factor of impact on the concentration of radon in groundwater, since strong earthquakes did not occur during the monitoring period.

Characterization of LFG Emissions Factors for MSW Landfills

Conform municipal solid waste (MSW) landfills will continue to be used, in the nearest future, in accordance with environmental protection legislation. Due to this fact, the environmental factors such as: water, air, fauna and vegetation, soil, as well as the human health will be affected. The Greenhouse Gases (GHG) emissions (CH4, CO2, N2O, other nitrogen oxides, water vapor steams) are taken into consideration being responsible for a great part of the world environmental changes, 3÷5%, approximately. It is to be noted that, on the national territories, the GHG emissions should be considered due to a bad management of those. The MSW landfilling allows collecting landfill gas (LFG) in a place by collection and treatment of CH4, CO2 and H2S, for economical purposes and human beings health protection. Methane (CH4) is a strong GHG but has economical value and in the same time, is an important energetic source. Collecting this gas involves important costs. Waste disposal have to be analyzed from the point of view of its enclosed constituents, humidity kept, permeability, biodegradation rate, compacting density, temperature inside the landfill body and atmospheric pressure variations. This article is dedicated to studying the parameters of LFG collection wells, which are used as part of vertical collection systems. For this purpose, the modeling approaches to the main processes occurring in the porous medium of the landfill (MSW) are taken into account.