The brief history of experimental research of cosmic ray variations in Yakutia

Some unknown historical facts of cosmic ray studies in the north-east of the former Soviet Union related to the Yakutsk scientific group are reported for the benefit of the international scientific community. It focuses on the founders of Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of Siberian Branch of Russian Academy of Sciences. A chronology of measurements of cosmic ray intensity variations since 1949 in Yakutia (Sakha Republic; NE Siberia) is given. In particular, for the first time the data of the first solar cosmic ray event registered at Yakutsk (GLE04), with a small ionization chamber S-2 (volume: 20 L) are presented. Moreover, the data of the large ionization chamber ASK-1 (volume: 950 L) for the 1953–2003 period useful for specialists in the field of cosmic ray variations are also shown.     

Cosmic ray anisotropy based on Yakutsk station in real time

The method has been developed to calculate galactic cosmic ray anisotropy parameters by using on-line data of the neutron monitor 24-NM-64 and muon telescope at the Yakutsk station. The preliminary analysis shows that characteristic changes in the anisotropy parameters caused by the first spherical harmonics of cosmic ray angular distribution are observed 1–2 days before the onset of the most part of large-scale geophysical disturbances on the Earth. There is reason to believe that the attraction of data of geophysical observations of other kinds will allow to develop the forecast methods for the arrival of large-scale interplanetary disturbances at the Earth.     

Fluctuations of cosmic rays and IMF in the vicinity of interplanetary shocks

Fluctuations of cosmic rays and interplanetary magnetic field upstream of interplanetary shocks are studied using data of ground-based polar neutron monitors as well as measurements of energetic particles and solar wind plasma parameters aboard the ACE spacecraft. It is shown that coherent cosmic ray fluctuations in the energy range from 10 keV to 1 GeV are often observed at the Earth’s orbit before the arrival of interplanetary shocks. This corresponds to an increase of solar wind turbulence level by more than the order of magnitude upstream of the shock. We suggest a scenario where the cosmic ray fluctuation spectrum is modulated by fast magnetosonic waves generated by flux of low-energy cosmic rays which are reflected and/or accelerated by an interplanetary shock.     

The effect of aerosols on climate and aerosol climatology on the basis of observations from space

Principal aspects of the effect of aerosols on climate are discussed and the possibilities of obtaining a climatic data set of global aerosols are analyzed. Based on the analysis of space images, new data have been obtained on gigantic dust outbreaks in various regions of the Earth. It has been shown that dust outbreaks can propagate over hundreds and sometimes thousands of kilometers. The western Sahara - Atlantic Ocean is the major region of propagation of these outbreaks. The continent-to-continent trajectories of dust clouds have been discovered (from Africa to the coast of America, from Central Asia to the Pacific Ocean). Maps of the sources of strong dust transformations have been studied and drawn. In particular, an anthropogenic dust source has been found out on the northeastern coast of the Aral Sea. A striped mesostructure of dust formations has been analyzed, determined by both the inhomogeneous surface and peculiarities of the eddy dust transport. The techniques have been discussed in detail for retrieving the parameters of aerosol size distribution and the vertical profiles of the coefficients of aerosol extinction in the stratosphere and lower mesosphere from the data on the brightness of the twilight and daytime horizon as well as occultation measurements of solar radiation attenuation by the atmosphere.The difficulty of reliably predicting possible environmental changes arises both from the problems of estimating complex interactions of numerous processes and from a lack of information concerning various environmental parameters. For example, an important factor in present day climatic changes is the increased dust content of the atmosphere due to man's activities. However, a reliable estimate of this influence is found to be impossible due to the absence of definitive data on the global distribution of atmospheric dust and the properties of dust in various parts of the world [4,5,13–15]. The impact of aerosols on climate has been discussed in detail in a number of monographs [12–15].Observations from space have opened up new possibilities for studying atmospheric dust. For this purpose, both the imagery and spectrometry of the Earth's atmosphere from space are used. Rather attractive are the prospects for laser sounding [1].     

Estimation of the solar proton spectrum in the GLE70 event

The GLE event on December 13, 2006 as observed by network station neutron monitor data is investigated (is considered). The GLE energetic spectrum suggested for this event is estimated taking into account the primary differential spectrum of galactic cosmic rays, coupling coefficients and integral multiplicities of concrete detectors at different latitudes and levels of observation. It is noted that the additional increase of solar protons is also manifested in the ionization chamber ASK-1 data at the Yakutsk station.