共查询到20条相似文献，搜索用时 375 毫秒
1.
R.R.S. De Mendonça J.-P. Raulin F.C.P. Bertoni E. Echer V.S. Makhmutov G. Fernandez 《Journal of Atmospheric and Solar》2011,73(11-12):1410-1416
We present results obtained at El Leoncito (CASLEO, San Juan, Argentina) with the CARPET charged particles detector installed in April 2006. The observed modulation of the cosmic ray flux is discussed as a function of its time variability and it is related to longer solar activity variations and to shorter variations during solar and geomagnetic transient activity. Short period (few minutes, few hours) cosmic ray modulation events are observed during rain time (precipitation) and significant variations of the atmospheric electric field. Complementary observations of the atmospheric electric field indicate that its time variations play an important role in the detected cosmic ray event. 相似文献
2.
The solar wind modulates the flux of galactic cosmic rays impinging on Earth inversely with solar activity. Cosmic ray ionisation is the major source of air's electrical conductivity over the oceans and well above the continents. Differential solar modulation of the cosmic ray energy spectrum modifies the cosmic ray ionisation at different latitudes, varying the total atmospheric columnar conductance. This redistributes current flow in the global atmospheric electrical circuit, including the local vertical current density and the related surface potential gradient. Surface vertical current density and potential gradient measurements made independently at Lerwick Observatory, Shetland, from 1978 to 1985 are compared with modelled changes in cosmic ray ionisation arising from solar activity changes. Both the lower troposphere atmospheric electricity quantities are significantly increased at cosmic ray maximum (solar minimum), with a proportional change greater than that of the cosmic ray change. 相似文献
3.
The cosmic ray flux through the atmosphere at different levels of solar activity is simulated. The Geant program package has been used to determine the atmospheric zones where the maximal contrast of the released ray energy originates between the periods of solar minimum and maximum. The geographic coordinates and altitudes of these zones have been calculated. The results can be used to search for statistical correlations between the solar activity variations and dynamics of atmospheric transparency. 相似文献
4.
The effect of solar and galactic cosmic ray variations on the duration of elementary synoptic processes (ESPs) in the Atlantic-European sector of the Northern Hemisphere has been studied. It has been found that solar cosmic ray (SCR) bursts result in an increase in the duration of ESPs, which belong to the western and meridional forms of atmospheric circulation. Forbush decreases in galactic cosmic rays (GCRs) are accompanied by an increase in the duration of ESPs, which belong to the meridional atmospheric circulation form, and in a decrease in the duration of ESPs, which are related to the western and eastern circulation forms. It has been assumed that the observed variations in the ESP duration are caused by the effect of short-period cosmic ray variations on the intensity of cyclonic processes at middle and high latitudes, namely, the regeneration of cyclones near the southeastern coast of Greenland after SCR bursts and the development of blocking anticyclones over the northeastern Atlantic, Europe, and Scandinavia during GCR Forbush decreases. 相似文献
5.
6.
Ilya G. Usoskin Laurent Desorgher Peter Velinov Marisa Storini Erwin O. Flückiger Rolf Bütikofer Gennady A. Kovaltsov 《Acta Geophysica》2009,57(1):88-101
A brief review of the research of atmospheric effects of cosmic rays is presented. Numerical models are discussed, that are
capable to compute the cosmic ray induced ionization at a given location and time. Intercomparison of the models, as well
as comparison with fragmentary direct measurements of the atmospheric ionization, validates their applicability for the entire
atmosphere and the whole range of the solar activity level variations. The effect of sporadic solar energetic particle events
is shown to be limited on the global scale, even for the most severe event, but can be very strong locally in polar regions,
affecting the physical-chemical properties of the upper atmosphere, especially at high altitudes. Thus, a new methodology
is presented to study cosmic ray induced ionization of the atmosphere in full detail using realistic numerical models calibrated
to direct observations. 相似文献
7.
In this paper, we present a new calculation of the atmospheric neutrino flux in the energy range 10–107 GeV, which reveals sizable differences in muon neutrino flux predictions obtained with known hadronic models. The calculation
is based on the method of solving nuclear cascade equations in the atmosphere, which takes into account the nonscaling behavior
of inclusive cross sections for particle production, the increase in the total inelastic hadron-nucleus cross sections, and
the non-power-law character of the primary cosmic ray spectrum. The efficiency of the method was recently tested in atmospheric
muon flux calculations. The results of neutrino spectrum calculations have been compared with Frejus, AMANDA-II, and IceCube
measurement data. 相似文献
8.
利用Morlet小波变换方法对北京宇宙线台站的地面宇宙线强度在地磁暴前后的变化特征进行分析,得到:1)在平静期,北京宇宙线数据存在准24h周期性的特征,且通过分析周期为12h的Morlet小波"模",发现值稳定,且小于0.6;2)以90天为时间窗口,对2004年7月地磁暴前后的小波频谱变化进行详细分析,发现当发生大地磁暴时,宇宙线的静日准24h周期被打破,其他周期的波动开始增强.进一步研究发现,周期12h的波动在大地磁暴数小时到1天左右会出现显著增强,这一现象在2001、2002和2004年期间的大地磁暴前得到验证.3)Morlet小波"模"数据的急速增大是发生地磁暴的先兆特征,当小波模变化达到一定的阈值就可能发生大磁暴.本文分析了周期为12h时小波的模数据,对强地磁暴事件进行统计,选定阈值0.6,并通过2003年的6次大地磁暴进行预报验证,结果表明该方法不仅能够对大地磁暴事件进行预报,而且提前量满足预报需求,为基于宇宙线实测数据预报地磁暴方法提供了重要基础. 相似文献
9.
O. I. Akhmetov 《Geomagnetism and Aeronomy》2009,49(5):664-669
The seasonal effect of the daily variations in the cosmic ray intensity on the conductivity of the Earth-high-conductivity layer column has been analyzed based on the observations of the cosmic ray intensity, atmospheric current, and electric field vertical component, performed from summer 2006 to spring 2007 at Apatity station. The method for correcting the measurements of the atmospheric current and electric field vertical component under complex tropospheric conditions by numerically simulating the spatial structure of the current and field lines in the observation region has been proposed. It has been indicated that cosmic rays are the main source of ions in the winter polar lower atmosphere and are responsible for the type of daily variations in the conductivity, whereas the daily variations in the atmospheric current more depends on the conductivity rather than on the vertical electric field. 相似文献
10.
The spatial and temporal structure of the effects of solar activity (SA) and galactic cosmic ray (GCR) flux variations on the lower atmosphere circulation has been studied based on NCEP/NCAR reanalysis archive for 1948–2006 and MSLP (Climatic Research Unit, UK) data for 1873–2000. It has been shown that the GCR effects on pressure variations are characterized by a strong latitudinal and regional dependence, which is determined by specific features of the tropospheric circulation in the studied regions. The distribution of the correlation coefficients for mean yearly values of atmospheric pressure with the GCR flux intensity is closely related to the position of the main climatological fronts. The periodic (∼60 years) changes in the correlation sign of the pressure at high and middle latitudes with Wolf numbers have been revealed. It has been suggested that the changes of the sign of SA/GCR effects on atmospheric pressure are caused by the changes of the macrocirculation epochs, which, in turn, may be related to large-scale processes on the Sun. 相似文献
11.
A. V. Belov R. T. Gushchina E. A. Eroshenko K. F. Yudakhin V. G. Yanke 《Geomagnetism and Aeronomy》2007,47(2):251-255
Results of the continuous ground-based monitoring of the cosmic ray flux by neutron monitors are used as an experimental material for many works devoted to studying cosmic ray variations. Long-term stability of detectors is the problem of an extreme importance. Two independent methods for estimating long-term stability of neutron monitor operation have been proposed. The quantitative estimates have been obtained for 90 detectors that operated and have been operating during more than one solar cycle. The conditions responsible for long-term stability of a detector and the causes of instability have been considered. 相似文献
12.
The distribution of the cosmic ray flux over the Earth is not uniform, but the result of complex phenomena within the Sun–Earth environment. A Forbush decrease (Fd) is a rapid decrease in the intensity of cosmic rays. A given Fd can appear in different forms at different locations of the Earth. An investigation of simultaneous observations of Fd events by a selection of cosmic ray stations remains a subject of interest among researchers and numerous methods of analysis can be found in literature. Although these studies have contributed significantly to our knowledge, the variability in the manifestations of Fds demonstrates that there are still open questions in this field. The present work suggests that multivariate analysis is a simple method that can be used to discriminate between globally simultaneous and non-simultaneous Fds. 相似文献
13.
V. P. Antonova N. N. Volodichev S. V. Kryukov A. P. Chubenko A. L. Shchepetov 《Geomagnetism and Aeronomy》2009,49(6):761-767
The unit for detecting thermal neutrons, which makes it possible to study variations in cosmic rays of the interplanetary
and geophysical origin, has been created at the high altitude cosmic ray station (3340 m above sea level) near the Earth’s
crust fault. It has been established that variations in thermal neutrons are of the same nature as high-energy variations
registered with a neutron supermonitor in the absence of seismic activity. The flux of thermal neutrons from the Earth’s crust
during seismic activity in December 2006 has been registered for the first time. The flux value is higher than the background
level by 5–6%. The method for detecting the flux of thermal neutrons from the Earth’s crust with the simultaneous registration
of high-energy neutrons has been proposed. 相似文献
14.
A.L. Mishev 《Journal of Atmospheric and Solar》2010,72(16):1195-1199
The cause of the correlation between cloud cover and cosmic ray intensity is still a subject of discussion. The atmospheric transparency is the primary signature of the atmospheric state. The ability to use neutron monitor and Cherenkov telescope data in order to study atmospheric processes is demonstrated. The recently designed lead free neutron monitor at the Basic Environmental Observatory Moussala (42.11N, 23.35E, 2925 m a.s.l.) is described. The possibility to use Cherenkov telescope measurements for estimation of atmospheric transparency is demonstrated on the basis of Monte Carlo simulations and experimental data. The Monte Carlo simulations are carried out with CORSIKA code assuming FLUKA and QGSJET II hadron interaction models. Experimental data from Cherenkov telescope are presented. Several physical mechanisms related to the influence of cosmic rays on the cloud cover, respectively, the atmospheric transparency are widely discussed. 相似文献
15.
We present a compelling similarity of impulsive nitrate enhancements observed in polar ice from the northern and southern hemispheres. This analysis concentrates on the period 1940–1950, during which time the first four recorded solar cosmic ray ground-level enhancements (GLEs) occurred. GLEs are strong solar proton events. We show that large and sudden enhancements in the nitrate records from both hemispheres were observed within weeks following the recorded solar cosmic ray ground-level event. The observation of impulsive nitrate enhancements simultaneously in both hemispheres shortly after a large fluence solar proton event is strong evidence in support of a causal connection and argues strongly for rapid transport of atmospheric nitrates generated through the polar atmosphere by energetic solar proton events. 相似文献
16.
Track densities of heavy cosmic rays have been studied in hypersthene crystals taken from seven known depths below a fusion crust in the Shalka meteorite. By comparing these with a theoretical model, a preatmospheric radius of 20 ± 2cm has been estimated for the meteorite, assuming it to have been originally spherical. The fossil track-length distributions show a prominent peak in the region of 12–15 μm; and this has been attributed, on the basis of accelerated-ion calibration experiments, to cosmic ray Fe ions. The value (≥0.38 ± 0.04) of relative abundance of Fe ions to the total Fe-group ions (20 ≤ Z. ≤ 28) found in the cosmic ray flux averaged over the last ～19 m.y. is shown to be broadly similar to those given by present-day measurements. 相似文献
17.
V. V. Shutenko I. I. Astapov N. S. Barbashina A. N. Dmitrieva R. P. Kokoulin K. G. Kompaniets A. A. Petrukhin I. I. Yashin 《Geomagnetism and Aeronomy》2013,53(5):571-579
The intensity of the atmospheric muon flux depends on many factors: the energy spectrum of primary cosmic rays and the state of the Earth’s heliosphere, magnetosphere, and atmosphere. The wide-aperture URAGAN muon hodoscope (Moscow, Russia, 55.7° N, 37.7° E, 173 m a.s.l.) makes it possible to investigate not only variations in the muon flux intensity but also temporal changes in the parameters of its angular distribution. These changes are analyzed using the vector of local anisotropy and its projections, which have different sensitivities to the parameters of modulation of both primary cosmic rays in the heliosphere and the Earth’s magnetosphere and secondary cosmic rays as they pass through the Earth’s atmosphere. The vector of local anisotropy is the sum of unit vectors (directions of the reconstructed muon tracks) normalized to the number of tracks. The results of an analysis of long-term variations in mean hourly projections of the vector of local anisotropy obtained from the 2007–2011 URAGAN hodoscope data are presented. 相似文献
18.
V. A. Dergachev P. B. Dmitriev O. M. Raspopov H. Jungner 《Geomagnetism and Aeronomy》2006,46(1):118-128
Direct and indirect data on variations in cosmic rays, solar activity, geomagnetic dipole moment, and climate from the present to 10–12ka ago (the Holocene Epoch), registered in different natural archives (tree rings, ice layers, etc.), have been analyzed. The concentration of cosmogenic isotopes, generated in the Earth’s atmosphere under the action of cosmic ray fluxes and coming into the Earth archives, makes it possible to obtain valuable information about variations in a number of natural processes. The cosmogenic isotopes 14C in tree rings and 10Be in ice layers, as well as cosmic rays, are modulated by solar activity and geomagnetic field variations, and time variations in these concentrations gives information about past solar and geomagnetic activities. Since the characteristics of natural reservoirs with cosmogenic 14C and 10Be vary with climate changes, the concentrations of these isotopes also inform about climate changes in the past. A performed analysis indicates that cosmic ray flux variations are apparently the most effective natural factor of climate changes on a large time scale. 相似文献
19.
《Journal of Atmospheric and Solar》2002,64(7):795-804
We report on the recent studies on the long-term influence of cosmic rays on the Earth's environment. While on short time-scales solar activity is the driver for atmospheric changes suspected to be due to cosmic rays, for long time-scales the heliosphere, i.e. the circumsolar region occupied by the expanding part of the Sun's atmosphere, has to be considered. The heliosphere is identified as an important shield against interstellar influences and hazards. It has been demonstrated by quantitative modelling that a change of the interstellar medium surrounding the heliosphere as a result of the Sun's quasi-Keplerian motion around the galactic center triggers significant changes of planetary environments caused by enhanced fluxes of neutral atoms as well as by the increased cosmic ray fluxes. We give a compilation of recent space science results of interest to the atmospheric science community. 相似文献
20.
The Global Atmospheric Electrical Circuit and Climate 总被引：2，自引：1，他引：2
R. G. Harrison 《Surveys in Geophysics》2004,25(5-6):441-484
Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescales. 相似文献