A Mechanism of Solar Variability Effect on Radiative Balance of the Earth Atmosphere

Possible mechanisms of solar-climatic connections, which may be of importance as over short and long time intervals, are discussed. The variations of energetic balance of Earth's climatic system for the last fifty years are estimated. It is ascertained that the disbalance between the flux of solar energy that comes to the Earth and radiates to space is of 0.1% for the last ten years. The suggested mechanism makes it possible to explain not only the observed variation of the enthalpy of the Earth's climatic system for the period 1910-1980, but also the climate anomalies during last thousand years: the climate optimum in 12 century, and"small glacial period" in 16-17 centuries.      

Regional tropospheric responses to long-term solar activity variations

The influence of ∼200-year solar activity variations (de Vries cyclicity) on climatic parameters has been analyzed. Analysis of palaeoclimatic data from different regions of the Earth for the last millennium has shown that ∼200-year variations in solar activity give rise to a pronounced climatic response. Owing to a nonlinear character of the processes in the atmosphere–ocean system and the inertia of this system, the climatic response to the global influence of solar activity variations has been found to have a regional character. The regions where the climatic response to long-term solar activity variations is stable and the regions where the climatic response is unstable, both in time and space, have been revealed. It has also been found that a considerable lag of the climatic response and reversal of its sign with respect to the solar signal can occur. Comparison of the obtained results with the simulation predictions of the atmosphere–ocean system response to long-term solar irradiance variations (T > 40 years) has shown that there is a good agreement between experimental and simulation results.     

Solar cosmic rays in the near Earth space and the atmosphere

Solar energetic particles (SEPs) constitute a distinct population of energetic charged particles, which can be often observed in the near Earth space. SEP penetration into the Earth’s magnetosphere is a complicated process depending on particle magnetic rigidity and geomagnetic field structure. Particles in the several MeV energy range can only access to periphery of the magnetosphere and the polar cap regions, while the GeV particles can arrive at equatorial latitudes. Solar protons with energies higher than 100 MeV may be observed in the atmosphere above ∼30 km, and those with energies more than 1 GeV may be recorded even at the sea level. There are some observational evidences of SEP influence on atmospheric processes. Intruding into the atmosphere, SEPs affect middle atmosphere odd-nitrogen and ozone chemistry. Since spatial and temporal variations of SEP fluxes in the near Earth space are controlled by solar activity, SEPs may present an important link between solar activity and climate. The paper outlines dynamics of SEP fluxes in the near Earth space during the last decades. This can be useful for tracing relationship between SEPs and atmospheric processes.     

The atmospheric cosmic- and solar energetic particle radiation environment at aircraft altitudes

Galactic cosmic rays interact with the solar wind, the earth's magnetic field and its atmosphere to produce hadron, lepton and photon fields at aircraft altitudes. In addition to cosmic rays, energetic particles generated by solar activity bombard the earth from time to time. These particles, while less energetic than cosmic rays, also produce radiation fields at aircraft altitudes which have qualitatively the same properties as atmospheric cosmic rays. We have used a code based on transport theory to calculate atmospheric cosmic-ray quantities and compared them with experimental data. Agreement with these data is seen to be good. We have then used this code to calculate equivalent doses to aircraft crews. We have also used the code to calculate radiation doses from several large solar energetic particle events which took place in 1989, including the very large event that occurred on September 29^th and 30^th of that year. The spectra incident on the atmosphere were determined assuming diffusive shock theory.     

Surface temperatures at the nearside of the Moon as a record of the radiation budget of Earth’s climate system

Understanding the balance between incoming radiation from the Sun and outgoing radiation from Earth is of critical importance in the study of climate change on Earth. As the only natural satellite of Earth, the Moon is a unique platform for the study of the disk-wide radiation budget of Earth. There are no complications from atmosphere, hydrosphere, or biosphere on the Moon. The nearside of the Moon allows for a focus on the solar radiation during its daytime, and on terrestrial radiation during its nighttime. Additionally, lunar regolith temperature is an amplifier of the terrestrial radiation signal because lunar temperature is proportional to the fourth square root of radiation as such is much more sensitive to the weak terrestrial radiation in nighttime than the strong solar radiation in daytime. Indeed, the long-term lunar surface temperature time series obtained inadvertently by the Heat Flow Experiment at the Apollo 15 landing site three decades ago may be the first important observation from deep space of both incoming and outgoing radiation of the terrestrial climate system. A revisit of the lunar surface temperature time series reveals distinct characteristics in lunar surface daytime and nighttime temperature variations, governed respectively by solar and terrestrial radiation.     

近地环境的电状态

通过电过程的耦合是太阳对气象耦合影响的机制之一,本文扼要地综述了迄今为止人们对近地环境内电流和电场的观测结果以及在此基础上所建立的经验和理论模式;给出了在平均状况下和太阳活动下近地环境电性能的总概貌,重点在靠近地球表面的低层、中层大气区域;着重介绍了该区域内的大气电性能及其受太阳活动的调制.      

Possible DC electric field in the ionosphere related to seismicity

This paper presents the method for calculation of DC electric field in the atmosphere and the ionosphere generated by model distribution of external electric current in the lower atmosphere. Appearance of such current is associated with enhancement of seismic activity that is accompanied by emanation of soil gases into the atmosphere. These gases transfer positive and negative charged aerosols. Atmospheric convection of charged aerosols forms external electric current, which works as a source of conductivity current in the atmosphere–ionosphere electric circuit. It is shown that DC electric field generated in the ionosphere by this current reaches up to 10 mV/m, while the long-term vertical electric field disturbances excited near the Earth surface do not exceed 100 V/m. Such limitation of the near-ground field is caused by the formation of potential barrier for charged particles at the Earth surface in a process of their transport from soil to atmosphere.     

Be-7 nuclei produced by galactic cosmic rays and solar energetic particles in the earth''s atmosphere

Be-7 radioactive nuclei with a half-life of 53.3 days result from spallation reactions of galactic cosmic rays(GCR) and solar energetic particles (SEP) with N and O nuclei in the Earth's atmosphere. We calculate the average global production of Be-7 in the atmosphere by GCR and SEP The result indicates that an intense SEP event produces a large amount of Be-7 in the polar stratosphere and part of them could be transported to the surface at lower latitudes. The ground-level measurement of Be-7 in Japan exhibits the possibility of enhancement in the Be-7 radioactivity associated with the intense SEP event on July 14, 2000. In addition, the present experiment shows seasonal variations in the surface Be-7 concentration which peaks in spring and autumn. We discuss the possible air mass mixing between the stratosphere and troposphere to explain the measured seasonal variations. The surface concentration of Pb-210 nuclei indicates a similar trend to that of Be-7 and we suggest two possible explanations.     

Total solar irradiance and climate

The solar radiation is the fundamental source of energy that drives the Earth’s climate and sustains life. The variability of this output certainly affects our planet. In the last two decades an enormous advance in the understanding of the variability of the solar irradiance has been achieved. Space-based measurements indicate that the total solar irradiance changes at various time scales, from minutes to the solar cycle.Climate models show that total solar irradiance variations can account for a considerable part of the temperature variation of the Earth’s atmosphere in the pre-industrial era. During the 20th century its relative influence on the temperature changes has descended considerably. This means that other sources of solar activity as well as internal and man-made causes are contributing to the Earth’s temperature variability, particularly the former in the 20th century.Some very challenging questions concerning total solar irradiance variations and climate have been raised: are total solar irradiance variations from cycle to cycle well represented by sunspot and facular changes? Does total solar irradiance variations always parallel the solar activity cycle? Is there a long-term variation of the total solar irradiance, and closely related to this, is the total solar irradiance output of the quiet sun constant? If there is not a long-term trend of total solar irradiance variations, then we need amplifying mechanisms of total solar irradiance to account for the good correlations found between total solar irradiance and climate. The latter because the observed total solar irradiance changes are inconsequential when introduced in present climate models.     

Possible influence of cosmic rays on climate through thunderstorm clouds

With decreasing of cosmic ray (CR) intensity caused by increasing of solar activity (SA) or in some short periods of Forbush-decreases, the intensity of secondary CR relativistic electrons decreases and the probability of formation of thunderstorm clouds and discharges between clouds or between clouds and ground is also expected to decrease. This will influence on weather and climate. In this case is very important to have more detail information on the atmospheric electric field distribution in the atmosphere, additional to information what gave now electric field sensors (EFS) only in about one point near the ground. We show that CR not only influenced on atmospheric electric field phenomenon, but can give practically continuous information on the atmospheric electric field distribution in the atmosphere. We extend our theory of CR atmospheric electric field effect on electron–photon, muon and neutron component including different multiplicities. We take into account that about 0.07 of neutron monitor counting rate caused by negative soft muons captured by lead nucleons and formed mesoatoms with generation of several MeV energy neutrons from lead. In this case the neutron monitor or neutron super-monitor works as analyzer that detects muons of only one, negative sign. It is very important because the atmospheric electric field effect have opposite signs for positive and negative muons that main part of this effect in the muon telescope or in ionization chamber is compensated and we can observe only small part of total effect of one sign muons. On the basis of our general theory of CR atmospheric electric field effects with taking into account of negative soft muon acceleration and deceleration in the Earth atmosphere (in dependence of direction and intensity of electric field) we discuss the possibility of existing this effect in CR neutron monitor counting rate and in different multiplicities and calculate the expected effects in dependence of atmospheric electric field distribution in the atmosphere. We show that the comparison of observed effects with theoretically expected will give important information on the value of atmospheric electric field and its distribution in the atmosphere. We consider also the possible influence of secondary relativistic electrons of CR and relativistic electrons precipitated from the Earth’s radiation belts on thunderstorms and lightnings, and through this – on climate change.     

1998年9月24日地磁暴前宇宙线各向异性特性分析

分析了日本Nagoya 宇宙线闪烁体望远镜30°, 49°, 64° 倾角的东、西、南、北方向探测数据的变化特点, 运用小波分析方法定性地探讨了磁暴前后宇宙线南北、东西各向异性的变化特征. 研究发现, 当发 生大地磁暴时, 地面宇宙线强度的各向异性特征将发生非常大的变化, 这种变化一般在磁暴发生前10~20 h就开始出现. 当描述这种各向异性特征的各向异性指数的小波系数变化达到一定阈值时, 就可能有大地磁暴发生.      

The Living With a Star (LWS) Sentinels

This paper gives a short account of the development of the living with a star Sentinels element. The Sentinels element is the heliospheric portion of the NASA program focused on improving our understanding of geo-effective events in the Sun–Earth connected system. The primary objectives of Sentinels are the investigation of the initiation and evolution of solar transients in the inner heliosphere, the acceleration and propagation of solar energetic particles, and the long term climatic change and structure of the inner heliosphere into which all of these geo-effective structures erupt. Due to the large volume of space to be covered, Sentinels will have to rely on, besides a dedicated mission, the observations of spacecraft from other programs of NASA and international partners along with a robust theoretical and modeling effort. The upcoming Sentinels Science and Technology Definition Team will develop specific details of this element.     

Is the Earth’s orbital motion linked to the spin rotation of the Sun?

Time variations of the magnetic field of the Sun, seen as a star (the data 1968–2018, with more than 27 thousand daily measurements of the solar mean magnetic field), allowed to specify the rotation period of the gravitating solar mass: 27.027(6)?days, synodic. This indicates a presumably unknown physical connection between motions of the Sun and the Earth: in the course of a year our star accomplishes nearly 27 half-revolutions, while the planet itself performs an identical number of its spinnings during one complete axial revolution of the Sun. True origin of this strange Sun–Earth resonance is unknown, but it is supposed the phenomenon might be caused by slight coherent perturbations of gravity within the solar system.     

Evaluation of solar proton spectra using balloon cosmic ray observations and Monte Carlo simulation results

We have developed a method to evaluate the spectrum of solar energetic protons at the top of the Earth’s atmosphere from the measurements of our balloon cosmic ray experiment. By using the Monte Carlo PLANETOCOSMICS code based on Geant4 we compute the interaction of solar protons [10 MeV–10 GeV] with the Earth’s atmosphere. We obtain the angular and energy distributions of secondary particles (p, e⁻, e⁺, photons, muons) at different atmospheric levels as a function of primary proton spectra. By comparing the calculated depth dependence of the particle flux with the data obtained by our balloon experiment we can deduce the parameters of the solar proton spectrum that best fit the observations. In this paper we discuss our solar proton spectrum estimation method, and present results of its application to selected solar proton events from 2001 to 2005.     

On the usefulness of atmospheric and oceanic angular momentum in recovering polar motion and gravity field variations in a unified process

Earth rotation parameters (ERPs) are excited by variations in the mass distribution on the Earth’s surface and the exchange of angular momentum between the atmosphere and oceans and the solid Earth. The same mass redistribution causes temporal changes in the gravity field coefficients with the second degree harmonics related to the rotational deformation and hence to changes in the Earth’s inertial tensor. If precise models of the atmospheric and oceanic angular momentum (AM) are available solution for polar motion and degree 2 Stokes harmonics can be unified. In this study we utilize SLR tracking of LAGEOS to compare (i) degree 2 harmonics from ERPs and gravitation, and (ii) LAGEOS excitation functions and geophysical data (mass + motion). Finally, we investigate to what extent a unified approach is possible with current models for AM data and gravity mass change estimated from ERP within orbit determinations.     

磁扰动和磁静时近地等离子体片中脉冲电场的分布

Ｇｅｏｔａｉｌ卫星的电场数据被用于分析近地磁尾等离子体片中电场在磁扰动（Ｄｓｔ＜－２５ｎＴ）和磁静时（Ｄｓｔ＞－２５ ｎＴ的统计分布．结果表明，伴随着地向高速离子流，在Ｘ＞－１６Ｒｅ以内区域出现强电场（高达 ５—８ ｍＶ／ｍ）．磁扰动期间强电场的幅值较磁静时大，并且出现在更靠近地球的位置．较强和较靠近地球的强电场与磁扰动时更薄的等离子体片和更接近地球的等离子体片内边界相联系．观测结果意味着磁扰动期间的亚暴可能更有效地将高能粒子注射到环电流中．这对磁暴和亚暴的关系问题的解决有重要意义．     

Longitudinal variations of the ionospheric trough position

For the first time a comprehensive pattern of the longitudinal effect of the ionospheric trough position was obtained. We present new results with longitudinal variations of the winter trough position as a function of geomagnetic latitude for both hemispheres and conditions of high and low solar activity and all local time hours. We used a large observational data set obtained onboard the Kosmos-900, Interkosmos-19 and CHAMP satellites for quiet geomagnetic conditions. We found that a magnitude of the trough position longitudinal effect averaged for a fixed local time is greater in the daytime (6–8°) than in the nighttime (3–5°). The longitudinal effect magnitude reaches its maximum (16°) in the morning (at 08 LT) in the Southern hemisphere at high solar activity. But on certain days at any solar activity the longitudinal effect magnitude can reach 9–10° even at night. The shape of the longitudinal effect was found to differ significantly in two hemispheres. In the Northern hemisphere the trough is usually closest to the pole in the eastern (American) longitudinal sector, and in the Southern hemisphere the trough is closest in the western (Eurasian) longitudinal sector. The magnitude and shape of the longitudinal effect is also different during low and high solar activity. The Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) simulations demonstrate that during low solar activity, the longitudinal variations of the daytime trough position is mainly determined by longitudinal variations of the ionization function, formed due to the longitudinal variations in the solar zenith angle and the atomic oxygen density distribution. The longitudinal variations of the nighttime trough position is formed by the longitudinal variations in ionization of precipitating auroral particles, neutral atmosphere composition, and electric field.     

Effects of various dissipation range onset models on the 26-day variations of low-energy galactic cosmic-ray electrons

The effect of various models presented by Leamon et al. (2000) for the dissipation range cutoff wavenumber on the 26-day variations of galactic cosmic-ray electrons in a Fisk-Parker hybrid field is investigated, by means of a three-dimensional steady-state numerical modulation code. Analytical expressions for the mean free paths parallel and perpendicular to the heliospheric magnetic field are adapted from the works of 31 and 28, respectively. Note that only solar minimum conditions are considered, and that only qualitative agreement with data is sought. Effective diffusion for galactic electrons pertaining to 26-day variations is found to be dominated by the ratio of the perpendicular to parallel mean free paths at low energies, and the relationship between changes in cosmic-ray intensities and the modulation parameter postulated by Zhang (1997) is found to no longer hold when this ratio drops below a critical value. Use of ion inertial scale dependent models for the dissipation range cutoff leads to possible second linearities in the relative amplitudes as functions of latitude gradient.     

The solar cosmic ray ground-level enhancements on 20 January 2005 and 13 December 2006

Close to the current solar activity minimum, two large solar cosmic ray ground-level enhancements (GLE) were recorded by the worldwide network of neutron monitors (NM). The enormous GLE on 20 January 2005 is the largest increase observed since the famous GLE in 1956, and the solar cosmic-ray event recorded on 13 December 2006 is among the largest in solar cycle 23. From the recordings of the NMs during the two GLEs, we determined the characteristics of the solar particle flux near Earth.     

太阳宇宙线源物质的高色球层模式和重离子丰度过量机制的探讨

本文利用太阳能量粒子事件中重离子平均丰度过量的资料,计算得到太阳能量粒子源物质的温度,提出了描述太阳宇宙线能量粒子源物质的新模式——高色球层模式;太阳耀斑观测确定,太阳宇宙线耀斑的加速区一般最可能出现在低日冕甚至高达几万公里的高度,从而,太阳宇宙线的源和加速区通常不位于同一区域;进而提出了描述太阳能量粒子事件中重离子丰度过量的可能机制——其源物质是通过太阳黑子的冻结型无力场从高色球层输送到活动区,形成耀斑前加速区内重离子丰度大和耀斑后宇宙线中重元素丰度的过量.