共查询到20条相似文献，搜索用时 609 毫秒
1.
I.G. Usoskin M. Voiculescu G.A. Kovaltsov K. Mursula 《Journal of Atmospheric and Solar》2006,68(18):2164-2172
Studies of the relation between cosmic rays (CR) (solar activity) and atmospheric cloudiness are mostly based on the satellite ISCCP cloud data. However, doubts have been cast that these relations can be an artifact of instrumental effects, i.e., of the masking/obscuring low clouds by higher clouds in the satellite view. If this is the case, most of the earlier results based on ISCCP data would be devaluated. Here, we reanalyze the ISCCP cloud coverage data and its relation with the cosmic ray-induced ionization, and show that the correlation between low clouds and CR is affected by higher clouds in some geographical regions, but not everywhere. In turn, our results show that low clouds also may affect the relation of higher clouds with CR in some regions. Accordingly, correlation analysis can be performed only when the strong relation between clouds of different types is taken into account. In particular, studies based on global or latitudinal (zonally averaged) cloud data should be revised. 相似文献
2.
The volumetric generation rate of secondary electrons, produced by cosmic radiation in the Earth’s atmosphere and able to accelerate in a thundercloud electric field, has been calculated as a function of height above sea level. It is recommended to use the obtained function as a source when modeling atmospheric breakdown in thunderstorm fields with the participation of relativistic runaway electron avalanches. It has been indicated that ionization of the atmosphere by a cosmic particle with an energy of 1016 eV cannot initiate lightning. 相似文献
3.
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
4.
The thermospheric and ionospheric effects of the precipitating electron flux and field-aligned-current variations in the cusp have been modelled by the use of a new version of the global numerical model of the Earths upper atmosphere developed for studies of polar phenomena. The responses of the electron concentration, ion, electron and neutral temperature, thermospheric wind velocity and electric-field potential to the variations of the precipitating 0.23-keV electron flux intensity and field-aligned current density in the cusp have been calculated by solving the corresponding continuity, momentum and heat balance equations. Features of the atmospheric gravity wave generation and propagation from the cusp region after the electron precipitation and field-aligned current-density increases have been found for the cases of the motionless and moving cusp region. The magnitudes of the disturbances are noticeably larger in the case of the moving region of the precipitation. The thermospheric disturbances are generated mainly by the thermospheric heating due to the soft electron precipitation and propagate to lower latitudes as large-scale atmospheric gravity waves with the mean horizontal velocity of about 690 ms–1. They reveal appreciable magnitudes at significant distances from the cusp region. The meridional-wind-velocity disturbance at 65° geomagnetic latitude is of the same order (100 ms–1) as the background wind due to the solar heating, but is oppositely directed. The ionospheric disturbances have appreciable magnitudes at the geomagnetic latitudes 70°–85°. The electron-concentration and -temperature disturbances are caused mainly by the ionization and heating processes due to the precipitation, whereas the ion-temperature disturbances are influence strongly by Joule heating of the ion gas due to the electric-field disturbances in the cusp. The latter strongly influence the zonal- and meridional-wind disturbances as well via the effects of ion drag in the cusp region. The results obtained are of interest because of the location of the 相似文献
5.
The increasing concentration of greenhouse gases in the atmosphere is expectedalso to modify the mesosphere and lower thermosphere (MLT region). However,the greenhouse cooling – instead of heating – at these heights is revealed by modelsand generally confirmed by observations. This should more or less affect variousionospheric parameters at these heights. The spatial and temporal structure oftemperature trends in the MLT region is quite complex and, therefore, such structureshould occur for trends in the lower ionosphere as well. In the lower part of theionosphere below about 90 km, the rocket measurements of electron density, theindirect phase reflection height measurements and the A3 radio wave absorptionmeasurements reveal trends corresponding to cooling and shrinking of the mesosphere,while riometric measurements of cosmic noise absorption provide inconclusive results.The radio wave absorption and rocket electron density measurements clearly display asubstantial dependence of trends on height. Ionosonde data show that there is amodel-expected trend in the maximum electron concentration of the E region ionosphere;foE is slightly increasing. On the other hand, the height of the normal E layer, h'E, isslightly decreasing. The nighttime LF radio wave reflection height measurements near95 km support an idea of increasing electron density. However, rather scarce rocketmeasurements display a negative trend in electron density at 90–120 km. The role ofthe solar cycle and other longer-term variability of natural origin in the determinationof observational trends must not be neglected. In spite of the general qualitativeagreement with model expectations, there is still some controversy between variousobservational trend results (hopefully, apparent rather than real), which needs to beclarified. 相似文献
6.
Numerical calculations of galactic cosmic ray (GCR) ionization rate profiles are presented for the middle atmosphere and lower ionosphere altitudes (35–90 km) for the full GCR composition (protons, alpha particles, and groups of heavier nuclei: light L, medium M, heavy H, very heavy VH). This investigation is based on a model developed by Velinov et al. (1974) and Velinov and Mateev (2008), which is further improved in the present paper. Analytical expressions for energy interval contributions are provided. An approximation of the ionization function on three energy intervals is used and for the first time the charge decrease interval for electron capturing (Dorman 2004) is investigated quantitatively. Development in this field of research is important for better understanding the impact of space weather on the atmosphere. GCRs influence the ionization and electric parameters in the atmosphere and also the chemical processes (ozone creation and depletion in the stratosphere) in it. The model results show good agreement with experimental data (Brasseur and Solomon 1986, Rosenberg and Lanzerotti 1979, Van Allen 1952). 相似文献
7.
Kazuho Horiuchi Tomoko Uchida Yuko Sakamoto Aoi Ohta Hiroyuki Matsuzaki Yasuyuki Shibata Hideaki Motoyama 《Quaternary Geochronology》2008,3(3):253-261
The cosmogenic nuclide 10Be was analyzed by using accelerator mass spectrometry on an ice core drilled at the Dome Fuji station, inland Antarctica, for 700–1900 yr CE. The measured concentration of 10Be in the Dome Fuji ice core and the derived 10Be flux show similar fluctuations, with both increasing at known solar-activity minima over the last millennium in agreement with earlier observations of 10Be and 14C. Based on the similar nature of the 10Be flux to the reconstructed 14C production rate patterns, a 10Be–14C correlation age model for the Dome Fuji ice core was successfully constructed. This age model agrees well with the initial version of the tephrochronology of the core. The 10Be-flux record contains information on variability in the amount of cosmic radiation incident on the atmosphere, which is mainly attributable to high-frequency change in solar activity and low-frequency background intensity adjustment of the geomagnetic field. High-resolution 10Be analyses of the Dome Fuji ice cores promise to provide potentially important information on the history of cosmic radiation intensity over the past several hundred thousand years. 相似文献
8.
We have used the thermodynamic model of the climate to estimate the effect of variations in the oceanic cloud cover on the surface temperature of the Earth in the North Hemisphere (NH) during the period 1984–1990. We assume that the variations in the cloud cover are proportional to the variation of the cosmic ray flux measured during the same period. The results indicate that the effect in the temperature is slightly noticeable when we consider the surface hemispheric temperature on July 1987, finding an average temperature anomaly between −0.06°C and −0.14°C, along a latitudinal band between 20° and 40°. The surface temperature averaged globally in the NH presents a decrease of 0.01°C in average, which is almost the same for continents and oceans. However, these values are not significant when compared to the overall variability of the time series with and without forcing. 相似文献
9.
J. La&#x;tovi
ka 《Journal of Atmospheric and Solar》2009,71(14-15):1514-1528
The global pattern of long-term trends and changes in the upper atmosphere and ionosphere has been presented by Laštovička et al. [2006a. Global change in the upper atmosphere. Science 314 (5803), 1253–1254]. Trends in the mesospheric temperature, electron concentration in the lower ionosphere, electron concentration and height of its maximum in the E-region, electron concentration in the F1-region maximum, thermospheric neutral density and F-region ion temperature qualitatively agree with consequences of the enhanced greenhouse effect and form a consistent pattern of global change in the upper atmosphere. Three groups of parameters were identified as not-fitting this global pattern, the F2-region ionosphere, mesospheric water vapour, and the mesosphere/upper thermosphere dynamics. The paper reports progress in development of the global pattern of trends with emphasis to these three open problems. There are several other factors contributing to long-term trends, namely the stratospheric ozone depletion, mesospheric water vapour concentration changes, long-term changes of geomagnetic activity and of the Earth's magnetic field. 相似文献
10.
P. H. Gregory 《Pure and Applied Geophysics》1978,116(2-3):309-315
The atmosphere near the ground contains a mixed population of pollen and spores in the 1 to 90 m diameter range. Continuous sampling at Rothamsted Experimental Station at 2 m above ground level indicated concentrations averaging 12,000 m–3 over 5 summer months, but 1 million m–3 can occur for short periods. Concentrations change rapidly with locality, season, time of day or night and weather. Normally concentration in the troposphere decreases logarithmically with height. The occurrence of long distance transport of pollen and spores by wind is demonstrated by sampling from aircraft, and supported by much circumstantial evidence. Possible effects of this air spora on the atmosphere may be sought in alterations to: opacity, ionization, condensation nuclei, and sinks for minor gases. 相似文献
11.
A. A. Krivolutsky A. A. Kuminov A. A. Kukoleva A. I. Repnev N. K. Pereyaslova M. N. Nazarova 《Geomagnetism and Aeronomy》2008,48(4):432-445
Using the data on solar proton fluxes measured on board the GOES satellites, the most powerful solar proton events (SPEs) of solar cycle 23 are selected, and ionization rates in the atmosphere in these periods at high latitudes of the Northern Hemisphere are calculated. Assuming that each ion pair formed at the retardation of solar protons in the atmosphere leads to the formation of 1.25 molecules of nitric oxide, 2.0 molecules of the OH radical, and one oxygen atom, changes in the content of ozone, nitrogen and other compounds were calculated using a photochemical model. The calculations showed that the strongest ionization and destruction of ozone was caused by SPEs that occurred on July 14, 2000; November 8, 2000; November 4, 2001; and October 28, 2003. The results can form the basis for compiling the catalog of changes in ionization and ozone in the atmosphere caused by solar proton activity. 相似文献
12.
Recent analysis of monthly mean cloud data from the International Satellite Cloud Climatology Project uncovered a strong correlation between low cloud and the cosmic ray flux for extensive regions of the Earth. Additional data have been recently released covering the period up to September 2001 with which we have made a new study of the geographical variation of the correlation between low cloud and predicted ionization level from cosmic rays at an altitude of 2 km. When analysed globally, we find that the correlations do not correspond to the latitude variation of cosmic ray flux and they are not field significant. Nonetheless they appear to be marginally field significant over broad latitude and longitude bands with a peak positive correlation at 50 degrees North and South and a tendency to negative correlation at lower latitudes. The correlation is strongest over the North and South Atlantic. Several of these features are consistent with the predictions of the electroscavenging process.We use a simple model to calculate the climatic impact should the correlation be confirmed. We show that, under the most favorable conditions, a reduction in low cloud cover since the late 19th century, combined with the direct forcing by solar irradiance can explain a significant part of the global warming over the past century, but not all. However, this computation assumes that there is no feedback or changes in cloud at other levels. 相似文献
13.
Significant quantities of aerosol aluminum are transported from continental regions through the atmosphere to the oceans. Enrichments in the concentration of dissolved aluminum in open ocean surface seawater suggest that dissolution of aerosol aluminum is an important source of dissolved aluminum to these waters. Atmospheric aerosols collected at Enewetak Atoll were exposed to seawater and artificial rain water to determine directly the importance of atmospheric deposition as a source of marine dissolved aluminum.The results of these experiments indicate that 8–10% of the aluminum in atmospheric aerosols of crustal origin over the North Pacific is soluble in seawater. Approximately 5–6% dissolves very rapidly ( < 0.6 hr). An additional 3–4% dissolves within 60 hr. This bimodal dissolution of aerosol aluminum of crustal origin suggests that this aluminum is present in two forms. The rapidly dissolving fraction is likely aluminum already weathered from primary minerals, while the more slowly dissolving fraction is probably aluminum from the aluminosilicate matrix.Nearly the same amount of aerosol aluminum dissolved in artificial rain water (pH= 5.5) in 6 hr as dissolved in seawater (pH= 8) in 60 hr. The lower pH appears to not only increase the dissolution rate but may also increase the quantity of aerosol aluminum that dissolves. Dissolved organic matter in seawater appears to have relatively little effect on aerosol aluminum dissolution.Considering measured total aerosol aluminum fluxes, aluminum dissolution of 5–10% would constitute the major source for dissolved aluminum in surface waters of the open North Pacific. The calculated residence time of dissolved aluminum in the upper 100 m of the tropical North Pacific ranges from 2 to 6 years. 相似文献
14.
J. Střeštik 《Annales Geophysicae》1998,16(7):804-811
The series of daily Ap-indices has been subdivided into pentades (1932–1936 etc.) and spectra with fine-frequency resolution have been calculated for the indices in each of these intervals. Daily sunspot numbers have been processed in the same way. The average spectrum from all spectra in the pentades, as well as the spectrum from the whole interval have been calculated, and significant peaks have been determined. There is a significant difference between the spectra in the pentades containing the solar activity minimum (1932–1936, 1942–1946 etc.) and those containing the solar activity maximum (1937–1941, 1947–1951 etc.). Most peaks can be interpreted as a response to solar rotation and to the structure of solar wind speed (two high-speed streams per solar rotation), both modulated by the 11-year, annual and semi-annual waves. No significant peak corresponding to the period of the synodic month, or its half has been found. This result suggests that the influence of lunar cycles on some natural phenomena (if any) is not mediated by geomagnetic activity. 相似文献
15.
O. Vittori A 《Pure and Applied Geophysics》1968,69(1):360-364
Summary Airborne particulate matter was sampled at Mt. Cimone, Italy, to determine the size distribution of black spherules in the 1–5 diameter range. The magnetic fraction of airborne particulate matter was separated by forcing air through a strong magnetic sampling device, where ferromagnetic particles accumulated on microscope slides.Sizes of the black spherules were determined by counting under a microscope. Samples were dissolved and analyzed for iron content. Distribution was found to be in agreement with that of deep-sea sediment and satellite high atmosphere samples. The rate of terrestrial accretion of cosmic matter composed of black spherules appears to be approximately 10–15 g cm–2 sec–1. 相似文献
16.
On the stationary charge distribution on aerosol particles in a bipolar ionic atmosphere 总被引：1，自引：0，他引：1
N. A. Fuchs 《Pure and Applied Geophysics》1963,56(1):185-193
Summary By the «limiting sphere» method the combination coefficients for gaseous ions and aerosol particles were calculated, allowing for the jump in ion concentration at the surface of the particles. Hence the stationary charge distribution on aerosol particles in a symmetrical bipolar ionic atmosphere was determined. The use of the Boltzmann equation for this purpose proposed by some authors is theoretically wrong asthis equation applies to equilibrium rather than to stationary states. In practice, the Boltzmann equation can be used for particles with radius 3·10–5 cm (under atmospheric pressure). Within this range the image forces and the jump in ion concentration may be neglected. The conditions of the applicability of the steady diffusion equations to the theory of the stationary charge distribution in aerosols are discussed. 相似文献
17.
Etch rates and etchable lengths of cosmic ray tracks in meteoritic crystals have been used by several workers to derive the charge spectrum of ancient cosmic rays. This is done by comparing the fossil cosmic ray track record with fresh accelerator-produced calibration tracks. These calibration tracks are generally produced at room temperature, while meteorites spend a high proportion of their lifetimes orbiting at large distances from the Sun ( 3–5 AU) and are, consequently, at much lower temperatures (typically 100–150 K) during most of their cosmic ray exposure ages. We have irradiated crystals of apatite, olivine, enstatite and diopside held at 77, 293, 473 and 573 K, with 2 MeV/nucleon81Br ions, and then etched them. We find that their track etching properties are dependent upon the temperature of the mineral during registration. The track etch velocity generally increases with registration temperature up to 300 or 500 K (the upper limit depending upon the type of crystal). Our results also indicate that the annealing sensitivity of fission tracks in fluorapatite may be influenced by the registration temperature. This temperature dependence has important implications not only for cosmic ray particle identification but also for fission track dating of meteorites in view of the fact that the meteorite parent bodies were at elevated temperatures at the beginning af their life when244Pu fission tracks were being generated abundantly. 相似文献
18.
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
19.
M. G. Ogurtsov 《Geomagnetism and Aeronomy》2007,47(1):118-128
Information about variations in solar activity and climate on the time intervals from 130 years to four–five last centuries, including results of instrumental measurements (Wolf numbers, actinometry, thermometry) and indirect indicators (ice core acidity, NO 3 ? ion concentration in polar ice, temperature tree-ring reconstructions), has been analyzed for the Northern Hemisphere and its high-latitude part. It has been obtained that the observed relation between secular variations in solar activity and near-Earth temperature resulted from the effect of the corresponding variation in aerosol transparency of the stratosphere on terrestrial climate. It has been also indicated that long-term variations in the aerosol content of the stratosphere can, in turn, be related to secular cycles in atmospheric ionization caused by variations in fluxes of ionizing cosmic particles. 相似文献
20.
The longitudinal profile of atmospheric cascades is sensitive to the energy, mass of the primary particle and to atmospheric state. In this work are compared ionization yield functions Y for winter, summer and US standard profiles of Earth's atmosphere. The various profiles are obtained on the basis of CORSIKA 6.52 code simulations using FLUKA 2006 and QGSJET II hadronic interaction subroutines. The energy deposit of proton induced cascade processes in the atmosphere is calculated for different types of atmospheres. The ion pair production in the atmosphere and the contribution of the different shower components, precisely the electromagnetic, muon and hadronic is estimated according applied atmospheric types. In addition simulations with different hadronic interaction models GHEISHA 2002, FLUKA 2006 and QGSJET II are carried out. The ion pair production in the atmosphere and the contribution of different shower components is estimated according the assumed hadronic interaction models. The yield function Y for total ionization, respectively, for the different components is compared. The observed differences are widely discussed. General conclusion concerning the application of various atmospheric profiles and hadron interaction models is carried out. 相似文献