首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
A joint analysis of paleodata on variations in cosmic ray fluxes, solar activity, geomagnetic field, and climate during the period from ～10000 to ～100000 years ago has been performed. Data on the time variations in the concentration of 14C and 10Be cosmogenic isotopes, which are generated in the Earth’s atmosphere under the action of cosmic ray fluxes modulated by solar activity and geomagnetic field variations, were used to detect variations in solar activity and the geomagnetic dipole. Information about climate changes has been obtained mainly from variations in the concentration of stable isotopes in the natural archives. A performed analysis indicates that the variations in cosmic ray fluxes under the action of variations in the geomagnetic field and solar activity are apparently one of the most effective natural factors of long-term climate changeability on a large time scale.  相似文献   

2.
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   

3.
本文介绍了宇宙线空间物理学在我国的形成和主要研究内容,包括:(1)空间探测,有火箭探测、卫星探测;地面宇宙线台站观测;宇宙线的水下测量;(2)宇宙线空间物理学研究,有宇宙线的日地传输;宇宙线强度变化与CME事件;宇宙线的源物质与加速过程;宇宙线的地球物理效应.最后提到宇宙线与人体健康,特别是流行性感冒、大的太阳质子事件与地震现象、太阳宇宙线事件与天气和气候等的统计研究.  相似文献   

4.
Modulation of galactic cosmic rays in cycles 19–23 of solar activity has been determined based on observations of their long-term variations on the ground and in the near-Earth space. The extreme values of long-term variations in cosmic rays, obtained from the data of continuous cosmic radiation monitoring on the ground and in the near-Earth space in the last five solar cycles, have been analyzed. The results are compared with the extrema in the characteristics of solar magnetic fields and the sunspot numbers in these cycles. The similarities and differences in cosmic ray modulation between different cycles are discussed.  相似文献   

5.
  相似文献   

6.
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   

7.
Based on observations of long-term variations in galactic cosmic rays (CRs) on Earth and in the near-Earth space, we have determined, using our own semiempirical model, modulation of galactic CRs during solar cycles 19–23. The modulation model relates CR variations to the characteristics of the solar magnetic field obtained for the surface of the solar wind source at distances of 2.50 and 3.25 solar radii. The main focus is CR behavior at the minimums of cycles 19–23 and specific features of CR modulation at a prolonged (as compared to previous cycles) minimum of cycle 23, which is still ongoing. CR modulation at minimums related to a change in the solar field dipole component during this period of the cycle has been considered. It is indicated that the long-term variations in CRs are better described if the last two years (2007 and 2008) of cycle 23 with anomalously low solar activity (SA) are included in the model. The role and value of the contribution of the cyclic variations in each index used in the proposed CR modulation model to the observed CR modulation have been estimated.  相似文献   

8.
We analyze variations in the rigidity spectrum of primary cosmic rays during Forbush effects recorded in cycles 20–24 of solar activity on the basis of data from the global network of neutron monitor stations processed by global survey. We investigate variations in the rigidity spectrum index of Forbush effects as a function of the solar activity level, phases of the effect, polarity the total magnetic field of the Sun, type and parameters of the source of cosmic ray modulation, etc. Comprehensive analysis of our results revealed regularities in the dynamics of the energy spectrum of galactic cosmic rays that reflect the dynamic processes occurring in the interplanetary space.  相似文献   

9.
The study of variations in the electron flux in the outer Earth radiation belt (ERB) and their correlations with solar processes is one of the important problems in the experiment with the Electron-M-Peska instrument onboard the CORONAS-Photon solar observatory. Data on relativistic and subrelativistic electron fluxes obtained by the Electron-M-Peska in 2009 have been used to study the outer ERB dynamics at the solar minimum. Increases in outer ERB relativistic electron fluxes, observed at an height of 550 km after weak magnetic disturbances induced by high-velocity solar wind arriving to the Earth, have been analyzed. The geomagnetic disturbances induced by the high-velocity solar wind and that resulted in electron flux variations were insignificant: there were no considerable storms and substorms during that period; however, several polar ground-based stations observed an increase in wave activity. An assumption has been made that the wave activity caused the variations in relativistic electron fluxes.  相似文献   

10.
The main data have been summarized, and the results, achieved using data from the worldwide network during the entire period of ground-based observations of solar cosmic rays (SCRs) from February 28, 1942, when they were discovered, have been generalized. The methods and equipment for registering SCRs have been described. The physical, methodical, and applied aspects, related to the SCR generation, as well as the SCR interaction with the solar atmosphere, transport in the IMF, motion in the Earth’s magnetosphere, and the affect on the Earth’s atmosphere, have been discussed. It has been indicated that the fundamental results were achieved in this field of space physics during 70 years of studies. Special attention has been paid to up-to-date models and concepts of ground-level enhancement (GLE). The most promising tendencies in the development and application of this effective method of solar-terrestrial physics have been outlined.  相似文献   

11.
Reconstructions of solar activity in the past epochs based on information on the past atmospheric content of the cosmogenic 14C isotope are nowadays actively discussed. The 14C isotope is generated in the atmosphere of the Earth under the influence of cosmic rays, and its concentration in annual tree rings carries information on the past solar activity. However, the concentration of this isotope in annual tree rings may also be influenced by climatic factors. In the present work, the possible correlation between variations in the 14C atmospheric content and in the Earth’s global temperature from the late 14th century to the middle of the 19th century is studied. It is shown that variations in global temperature may produce changes in the 14C atmospheric content and consequently have to be taken into account in reconstructions of the past solar activity.  相似文献   

12.
Long-period variations in the cyclonic activity at middle and subpolar latitudes of the North Atlantic are studied on the basis of the data from the MSLP archive of the surface pressure (Climatic Research Unit, UK) for 1874–1995. It has been found that in the cold half year (the period of the most intense formation and development of extra-tropical cyclones) in the studied region, oscillations of the surface pressure with periods close to the main periods of solar activity (～80 and ～11 years) are observed. The obtained results make it possible to assume that solar activity and related variations in the galactic cosmic rays are one of the factors influencing the intensity of cyclonic processes at midlatitudes on the time scales of ～10 to ～100 years.  相似文献   

13.
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   

14.
We analyze the longest temperature series from Prague, Bologna and Uccle. We partition daily minimum and maximum temperatures and their differences in two subsets as a function of high vs low solar activity, using the superimposed epochs method. Differences display patterns with significant amplitudes and time constants ～3 months. These are recognized in all stations and are stable against a change in the analyzed period. Amplitude of variations is ～1 °C. Differences between average annual values corresponding to high vs low activity periods are also ～1 °C. Solar activity may account for these long-term temperature variations. These variations also present local characteristics, which may render identification of a global correlation delicate. We discuss possible physical mechanisms by which solar variation could force climate changes (e.g. through solar activity itself, the EUV part of the solar flux, cosmic rays, the downward ionosphere-earth current density, etc.).  相似文献   

15.
The influence of helio/geophysical factors on the solar energy input to the lower atmosphere has been studied at the network of actinometric stations of Russia in different latitudinal belts. It was found that there are appreciable changes in the half-yearly values of total radiation associated with galactic cosmic ray (GCR) variations in the 11-yr solar cycle, the increase of GCR flux being accompanied by a decrease of the total radiation at higher latitudes and by its increase at lower latitudes. Auroral phenomena and solar flare activity are likely to affect the solar radiation input to the high-latitudinal belt together with GCR variations, the increase of both these factors resulting in the decrease of total radiation. The changes found in the total radiation fluxes in the lower atmosphere seem to be related to the cloud cover variations associated with the solar and geophysical phenomena under study. The variations of the solar radiation input in the 11-yr-cycle amounting to ±4–6% may be an important factor affecting tropospheric dynamics.  相似文献   

16.
Evidence of the solar activity modulation of the Earth’s climate has been observed on several parameters, from decadal to millennial time scales. Several proxies have been used to reconstruct the paleoclimate as well as the solar activity. The paleoclimate reconstructions are based on direct and/or indirect effects of global and regional climate conditions. The solar activity reconstructions are based on the production of the 14C isotope due to the interaction of cosmic ray flux and the Earth’s atmosphere. Because trees respond to climate conditions and store 14C, they have been used as proxies for both for climate and solar activity reconstructions. The imprints of solar activity cycles dating back to 10,000 years ago have been observed on tree-ring samples using 14C data, and those dating back to 20 million years ago have been analyzed using fossil tree-growth rings. All this corresponds to the Cenozoic era. However, solar activity imprints on tree rings from earlier than that era have not been investigated yet. In this work, we showed that tree rings from the Mesozoic Era (of ~200 million years ago) recorded 11- and 22-year cycles, which may be related to solar activity cycles, and that were statistically significant at the 95 % confidence level. The fossil wood was collected in the southern region of Brazil. Our analysis of the fossils' tree-ring width series power spectra showed characteristics similar to the modern araucaria tree, with a noticeable decadal periodicity. Assuming that the Earth’s climate responds to solar variability and that responses did not vary significantly over the last ~200 million years, we conclude that the solar–climate connection was likely present during the Mesozoic era.  相似文献   

17.
The level of scattered radiation is analyzed using data of diurnal solar coronograph observations at the Mountain Astronomic Station in the period 1957?C2010 around coronal spectral lines at 5303 ? and 6374 ?. The observations were performed near the solar limb and were normalized by the intensity of the solar disk center. The measurements revealed variations on different timescales: seasonal variations, local maxima on timescales of a few years, and long-term trends. The local changes in the level of scattered radiation were found to be probably due to volcanic eruptions. An analysis revealed a tendency towards an increased in scattered radiation by approximately 40% during the last 50 years. The variations in the level of scattered radiation are compared with the concentration of atmospheric aerosols. The long-term growth in scattered radiation compares well with changes in the Earth??s near-surface temperature and is possibly associated with global climate change.  相似文献   

18.
During the prolonged and deep minimum of solar activity between cycles 23 and 24, an unusual behavior of the heliospheric characteristics and increased intensity of galactic cosmic rays (GCRs) near the Earth’s orbit were observed. The maximum of the current solar cycle 24 is lower than the previous one, and the decline in solar and, therefore, heliospheric activity is expected to continue in the next cycle. In these conditions, it is important for an understanding of the process of GCR modulation in the heliosphere, as well as for applied purposes (evaluation of the radiation safety of planned space flights, etc.), to estimate quantitatively the possible GCR characteristics near the Earth in the upcoming solar minimum (~2019–2020). Our estimation is based on the prediction of the heliospheric characteristics that are important for cosmic ray modulation, as well as on numeric calculations of GCR intensity. Additionally, we consider the distribution of the intensity and other GCR characteristics in the heliosphere and discuss the intercycle variations in the GCR characteristics that are integral for the whole heliosphere (total energy, mean energy, and charge).  相似文献   

19.
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   

20.
The relation of the fluxes of relativistic electrons in geostationary orbit during magnetic storms to the state of the magnetosphere and variations in the solar wind parameters is studied based on the GOES satellite data (1996–2000). It has been established that, in ～52–65% of all storms, the fluxes of electrons with energies higher than 0.6 and 2 MeV during the storm recovery phase are more than twice as high as the electron fluxes before a storm. It has been indicated that the probability of such cases is closely related to the prestorm level of fluxes and to a decrease in fluxes during the storm main phase. It has been found that the solar wind velocity on the day of the storm main phase and the geomagnetic activity indices at the beginning of the storm recovery phase are also among the best indicators of occurrence of storms with increased fluxes at the storm recovery phase.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号