We study the 25 July 2004 event. By analyzing SOHO EIT images we establish a basic understanding of the large-scale interaction going on during this event. Magnetic reconnection between the expanding CME and the Southern hemispheric active regions (AR) will connect the leading polarities of the two ARs, lead to brightening in the ARs and transport CME field line foot points to distant ARs (observable as dimming at the foot points).We reproduce the large scale interactions during this event using three-dimensional magneto-hydrodynamic (MHD) simulations. We superimpose a magnetic source region that resembles the SOHO MDI images on a basic wind model. By emerging new flux at the centre of this region we initiate a Coronal Mass Ejection (CME). We monitor the evolution of this CME and study its interaction with the source region.

We investigated the characteristics of the events occurred on October/November 2003 and May2005, the properties of the correlated observations of ionospheric absorption, of the critical frequency of the ionospheric F2 layer and of geomagnetic activity at the ground level. Solar events are studied using the characteristics of CME and the temporal evolution of solar energetic particles in different energy ranges.
We have tried to determine: possible clues that could allow a forecast evaluation of the effects produced at the Earth's orbit by the interplanetary perturbations and as these effects are observed on the ionosphere and on the geomagnetic field, using some Antarctic observations.

Power-height (PH) observations of the radio echo reflected from the ionosphere were performed every 15 min at a frequency of 3 MHz at the Rome ionospheric observatory, during the period 3-22 January 2008. This work describes a computer software program (Coerenza) that is able to calculate the maximum coherence times of the ionosphere from PH data. Some examples of the use of the output data obtained by Coerenza will be shown and discussed.

We propose a new approach to the problem of real-time space weather modelling using readily available data from ACE and a number of ground stations. It is based on the regression modelling method [1-3], which combines the benefits of empirical and statistical approaches. It is capable of forecasting Dst, ap and Kp indices 3 hours ahead with high accuracy for different types of the solar wind. It can be also extended to forecast solar activity 1-2 days ahead. The typical elapsed time per forecast is a few seconds on an average PC. The proposed system can also be used for investigation of physical phenomena related to interactions between the solar wind and the magnetosphere, in particular uncovering new geoeffective parameters.

1. Parnowski A.S. Regression modeling method of space weather prediction // Astrophysics & Space Science. - 2009. - V. 323,¹ 5 P. 169-180. doi:10.1007/s10509-009-0060-4 [arXiv:0906.3271]
2. Parnovskiy A.S. Regression Modeling and its Application to the Problem of Prediction of Space Weather // Journal of Automation and Information Sciences. - 2009. - V. 41, ¹ 5. - P. 61-69. doi:10.1615/JAutomatInfScien.v41.i5.70
3. Parnowski A.S. Statistically predicting Dst without satellite data // Earth, Planets and Space. - 2009. - V. 61, ¹ 5. - P. 621-624.

Atmospheric drag, which is the least accurately modeled force for satellites in low Earth orbit, is today estimated by means of thermosphere models. A key input of such models is the solar spectral irradiance in the UV/EUV range, which is essential to characterize the amount of solar energy the upper atmosphere receives.
Variations in the energy received cause variations in density, the largest of which are related to the approximately 11-year solar cycle and the 27-day solar rotation. An upper atmosphere model requires a representative, accurate and uninterrupted measurement or proxy measurement of the solar UV/EUV emissions. In fact, F10.7 is the only observation available that meets the listed criteria, but several other proxies for solar activity are tested in this study too. Finding more appropriate solar inputs has become crucial to specify the effect of air drag on satellites and on debris. In most cases, such solar inputs have been defined by very empirical means, without a systematic comparison of their performance.

Using 17 years of mean densities inferred from observed orbit perturbations of the French STELLA satellite and a large selection of solar activity proxies, we provide a quantitative assessment of the performance of each proxy. We do this on different time scales as the performance of the proxies is found to be quite different for short (on the order of days to weeks) and long (months to years) time scales. This study establishes which solar inputs are most appropriate at each time scale and provides guidance on the choice of a better proxy or combination of proxies for operational density models. In particular, we show that a scale-dependent combination of proxies is required in order to properly model the impact of solar irradiance. This first part of the study focuses only on the solar irradiance proxies; the complete analysis of selected solar irradiance proxies together with the available geomagnetic activity proxies will be performed in the future.

After a geomagnetic storm the magnetosphere takes some time to recover to its quiet state. The largest geomagnetic storm happened on 2 September 1859, when a variation on the geomagnetic horizontal component, H, of 1600 ±10 nT was registered at Colaba Observatory. The quiet time value of H at Colaba was registered again about two hours later. However, for other weaker storms with H variations on the order of 100 nT it takes more than 1 day in reaching quiet time again. These observations are enough to state that the time that magnetosphere takes to reach quiet time after a disturbance depends strongly on the severity of the disturbance.
The recently published hyperbolic model (Aguado et al., 2010) for the recovery phase has been applied in this work for the historical largest storms where data were available, obtaining the recovery time of these events as an output of the model. The analysis of these so severe events, let to show that the recovery time is not a linear function of Dst peak value, butan exponential law, which can be approached to a linear relationship for storms with Dst peak value between -400 nT and -100 nT, in agreement with the work of Aguado et al. (2010).

The effects of galactic and solar cosmic rays (CR) in the middle atmosphere are considered in this work. We take into account the CR modulation by solar wind and the anomalous CR component also. In fact, CRs determine the electric conductivity in the middle atmosphere and influence the electric processes in it in this way. CR introduce solar variability in the terrestrial atmosphere and ozonosphere. A new analytical approach for CR ionization by protons and nuclei with charge Z in the lower ionosphere and the middle atmosphere is developed in this paper. For this purpose, the ionization losses (dE/dh) for the energetic charged particles according to the Bohr-Bethe-Bloch formula are approximated in three different energy intervals. More accurate expressions for CR energy decrease E(h) and electron production rate profiles q(h) are derived. q(h) is determined by the solution of a 3D integral with account of geomagnetic cut-off rigidity.

The integrand in q(h) gives the possibility for application of adequate numerical methods - in this case Gauss quadrature and Romberg extrapolation, for the solution of the mathematical problem. Computations for CR ionization in the middle atmosphere are made. The contributions of the different approximation energy intervals are presented. In this way the process of interaction of CR particles with the upper and middle atmosphere are described much more realistically. The full CR composition is taken into account. The computations are made for different geomagnetic cut-off rigidities R in the altitude interval 35-120 km. The COSPAR International Reference Atmosphere CIRA'86 is applied in the computer program for the neutral air density and scale height values. The proposed improved CR ionization model will contribute to the quantitative understanding of solar-atmosphere relationships.

The interval ionization rate estimation includes the electron production rate of the charge decrease interval and of both intermediate intervals which couple the main three energy intervals of the ionization losses function in the improved CR interaction model. These investigations are based on particle ionization theory developed by Bohr, Bethe and Bloch, on the base of quantum mechanics. Moreover, for the altitude above 50 km, one can further neglect energy changes of the high energetic particles, thus reducing the cosmic ray induced ionization (CRII) computation to an analytical thin target model. In the altitude range from 25-30 to 50 km, an intermediate target model needs to be used, that accounts also for the particle's deceleration due to ionization losses. The analytical and numerical full target model includes an analytical approximation of the direct ionization by CR primaries as well as CORSIKA/FLUKA programme system Monte-Carlo simulations with account of hadron interactions.

Our improved ionization rate model is important for investigation of the different space weather effects. The cosmic rays and XUV radiations determine to a great extent the chemistry and electrical parameters in the middle and upper atmosphere, where are situated strato-mesosphere and thermosphere. They create ozonosphere and influence actively the stratosphere ozone O₃ processes. But the ozonosphere controls the meteorological solar constant and the thermal regime and dynamics of the lower atmosphere, i.e. the weather and climate processes. CR influence dominates during the night and sunrise-sunset periods, because galactic CR are always bombarding the Earth atmosphere. The CR flux varies during the solar cycle in an opposite face to that of sunspots. This hypothesis of the solar-terrestrial relationships shows the way to a non-contradictory solution of the key problems of the solar-terrestrial physics.

The structure of the proposed model allows its decomposition in several submodels. In this case we take into account the physical meaning of the undependent variables subintervals. The ionization losses function is calculated taking into account the energetic particles charge decrease interval. The energy intervals investigation takes place according to the goal of the user of the model with respect to accuracy and interval types.

REFERENCES

Dorman, L. Cosmic Rays in the Earth's atmosphere and underground. Kluwer Academic Publishers, Dordrecht, 2004.

Velinov, P.I.Y., Dorman, L., Nestorov, G. Cosmic ray influence on the ionosphere and on radiowave propagation. Sofia, BAS Publ. House, 1974.

Press, W.H., Flannery, B.P., Teukolsky, S.A., Vetterling, W.T. Numerical Recipes in C++ - The Art of Scientific Computing. Cambridge University Press, Cambridge, 2002.

Ruder, H., Velinov, P.I.Y., Mateev, L.N. Compt. rend. Acad. bulg. Sci. 59 (7), 717-722, 2006.

Velinov, P.I.Y., Mateev, L.N. J. Atmosph. Sol.-Terr. Phys. 70, 574-582, 2008.

Velinov, P.I.Y., Ruder, H., Mateev, L.N. Compt. rend. Acad. bulg. Sci. 59 (7), 723-730, 2006.

Velinov P.I.Y., Mateev, L.N. Adv. Space Res., 42, 1586 - 1592, 2008.

The full chain of physical processes in the Sun-Earth system is extremely complex. In this presentation, we illustrate how we can use a suite of models, residing at CCMC (Community Coordinated Modeling Center), along with available observations, to understand the initiation, evolution and interaction of solar disturbances and their consequences for the near-Earth region/other planets. In addition, we will show how some of the research grade models, if running in an operational mode, can help address space weather needs by providing forecasting/nowcasting capabilities of significant space weather events. We will focus on two events that occurred in the year of 2010: the 3-6 April event that potentially caused the failure of the Galaxy 15 spacecraft, and the 1-5 August event that received broad media attention worldwide. The main models that we are going to use include the WSA+ENLIL+Cone model covering the Sun to 1 AU of interplanetary space, SWMF (Space Weather Modeling Framework) for the Earth's bowshock and magnetosphere, RBE for assessing the near-Earth radiation environment and auroral models for characterizing particle precipitation at the ionosphere.

The solar magnetic field plays indisputable a crucial role in the existence of solar eruptive events. The general consensus is that the energy needed to drive the eruption is provided through the magnetic field. The strength and morphology of the solar magnetic field is expected to have a determining effect on the CME properties, like size and speed. Large scale eruptions often disturb regions on the solar surface remotely from the eruption's source region, pointing to the importance of the large scale coronal field.
In this numerical study we investigate the evolution of a magnetic structure when driven by different boundary motions, or when immersed into a different ambient magnetic field. The aim of this study is to get a better insight in the trigger and onset of CMEs. The simulations are carried out in the framework of ideal MHD, where the MHD equations are solved on a three dimensional spherical grid. We will present the preliminary results of this study.

We present a numerical simulation of the proton event observed on March 1, 1979 by Helios-1, Helios-2 and IMP-8/ISEE-3 spacecraft. Of particular interest in this gradual solar energetic particle (SEP) event is the spatial configuration of these spacecraft: they are located at similar radial distances from the Sun (from 0.93 to 0.99 AU) but showing a significant spread in longitude with respect to the site of the associated solar source (from E58 to W08). Such an interplanetary scenario gives us an opportunity to test the capabilities of a new Shock-and-Particle model (developed within the frame of the Solar Energetic Particle Environment Modelling (SEPEM) project (ESA)) with the aim to take into consideration the contribution of the shock-accelerated particle population in space weather-oriented SEP prediction models. We simulate the shock propagation starting close to the Sun and fit both the solar wind background and the shock arrival time and some of the plasma jumps observed at each spacecraft. The model also allows the reproduction of the proton flux profiles in the upstream region of each measured SEP event, for different energy channels between 1.3 MeV and 87 MeV protons. We quantify the efficiency of the shock at injecting particles in its way toward each observer and discuss these results regarding the angular separation of the spacecraft. We also discuss the simulated scenario in terms of the derived particle transport conditions.

The paper investigates the association between high long-lasting solar /geomagnetic activity and pressure distribution changes in the winter lower atmosphere. The analysis maps Northern Hemisphere winter periods (December - March) in 1951-2003. Solar/geomagnetic activity is characterized by 30 day mean of R number/ by 30 day mean of daily sum Kp index respectively. Lower atmosphere pressure distributions are described by 30 day mean anomalies in geopotential height throughout the vertical profile (20 hPa - 850 hPa). Data are taken from NCEP/NCAR reanalysis. The evaluations of 30 day mean values of solar/geomagnetic activity and pressure anomalies were made with a five day step through the whole winter period. The composite maps, representing difference between high (R≥90) and low (R≤70) solar activity and high (Kp≥19) and low (Kp≤17) geomagnetic activity, show significant pressure decreases in the stratospheric polar region and appearance of a positive phase of the North Atlantic Oscillation in the troposphere in early winter (December - January). The phase is more closely associated with geomagnetic than solar activity. In late winter (February - March) significant pressure decreases appear in the troposphere only. This tendency applies specifically to the North Atlantic and northeast Pacific area. Statistical significance was evaluated using the Monte Carlo method.

In this report we present an analysis of the ionospheric response to moderate (Dst<70 nT), 11 October 2008, geomagnetic storm. TEC maps over European region were created on the base of GPS observations provided by IGS/EPN.
Strong short-term positive effect was detected near noon of 11 October 2008. The TEC enhancement exceeded 100% on latitudes of 65-35N and was decreased to lower latitudes. The positive effect was associated with large scale traveling disturbance. During storm there was observed the increase and modification of horizontal gradients structure and ionospheric trough had moved to equator, until 57-58 geomagnetic latitudes.

The electron density profiles, retrieved from the Formosat-3/COSMIC radio occultation measurements and also measurements from European ionospheric sounding stations (DIAS), were analyzed within the case-study to estimate the altitudinal modification of the ionosphere. The considerable enhancement of the peak electron density was observed in European region during 11-15 UT, it reached the factor of 2.8 in comparison with quiet conditions. The height of the ionospheric F2 layer was risen by 60 km. For graphical demonstration of the observed ionospheric effects global electron density maps were calculated on the base of globally distributed COSMIC RO profiles. Electron density maps for different altitude slices were analyzed. This positive effect was revealed distinctly in RO electron density profiles and products based on these data - ionospheric electron content and global maps of electron density.

The "Advanced Thermosphere Model for Orbit Prediction (ATMOP)" research project aims at building a new thermosphere model with the potential to spawn an operational version. It will enable precise air drag computation, which is mandatory for improved survey and precise tracking of objects in Low Earth Orbit and the initiation of appropriate measures to minimise risks to satellites and ground assets.
With thousands of objects orbiting the Earth and the majority of them in LEO, survey and tracking of the larger specimens among these objects becomes an indispensable task for space agencies and satellite operators. Orbit determination methods are used to predict the trajectory of the objects hours to days ahead, and the estimated orbits are updated each time an object is tracked. For the sake of operations, it is obvious that an accurate orbit prediction is necessary to locate an object in time and space in order not to loose connection. To minimise the risks coming from space objects, accurate knowledge of the orbits of all objects in space that can pose a risk on space (due to possible collisions) or ground assets (due to re-entry objects) is needed. This requires an accurate thermosphere model.
The thermosphere can vary rapidly and significantly in response to solar and geomagnetic activity (space weather), i.e., accurate orbit prediction requires accurate space-time nowcast and forecast of the thermosphere. Despite the presence in Europe of one of the three groups that have the capability to develop and maintain an operational semi-empirical thermosphere model (CNES/CNRS, the other two are in the US), and of one of the world's leading teams in the field of physical modelling of the atmosphere (UCL), Europe has currently neither a near-real-time thermosphere prediction model nor operational services to provide regular thermosphere nowcast and forecast.
The ATMOP project is designed to fill this gap through:
* Defining and assessing new proxies to describe the external forcing of the thermosphere;
* Developing an advanced semi-empirical Drag Temperature Model (DTM) that meets the requirements for operational orbit computations;
* Improving physical modelling of the thermosphere to assist the development of the advanced DTM and of a global physical model with data assimilation capabilities, which may ultimately become the successor to semi-empirical models;
* Developing schemes for near-real-time assimilation of thermospheric and ionospheric data into an advanced predictive DTM and into the physical Coupled Middle Atmosphere-Thermosphere (CMAT2) model.
The updated semi-empirical DTM that will be constructed in the framework of the ATMOP project will be based upon the most comprehensive database available to researchers. It will in particular include densities inferred from accelerometers onboard CHAMP and GRACE, which supplied high quality thermospheric density data over almost one solar cycle, including years of high geomagnetic activity (2003) and exceptional low solar activity (2008 -2010).
Survey and tracking of LEO objects is a task that involves more than geodetic and engineering tools, it involves solar and space science and aeronomy. The first and almost immediate external forcing of the thermosphere results from the direct interaction between EUV radiation and the neutral atmosphere: it predominantly drives the medium and long-term evolution of the thermosphere, (time scales of days to years). The second forcing process results from the solar wind impact on the magnetosphere and its coupling to the ionosphere and the complex interaction between the neutral and ionized components of the Earth atmosphere: it mostly drives short-term changes in response to rapid variations in the solar wind conditions, and the associated geomagnetic activity. The latter forcing process can be described in terms of energy deposition in the auroral zone and subsequent heat transport to mid and low latitudes. Because of the short time lag between geomagnetic forcing and the thermosphere response only rapid thermosphere modelling can be efficiently used for satellite orbitography and debris surveillance. The ultimate objective of our project is to perform precise thermosphere modelling within a time delay that will eventually enable operational thermosphere nowcasting and which we call 'near real-time' modelling.
Our model will have the potential to be adopted by national and European space agencies for operational tasks. Therefore, ATMOP contributes to ensuring the security of space assets from space weather events and the development of the European capability to reduce dependence of space operations on the US. It is included in the frame of the EU FP7 Space Call 3, FP7-SPACE-2010-1. It addresses the area 9.2.3 "Research into reducing the vulnerability of space assets"and is designed to support the development of operational measures to insure the "Security of space assets from space weather events" (SPA.2010.2.3-01).

An analytical model which generalizes the differential galactic cosmic ray spectrum in the heliosphere is proposed. The model parameterizes the spectrum at different physical conditions, including the most important effects controlling the cosmic ray intensity like diffusion - convection and energy losses.
Force-Field (FF) formalism is a good approximation for galactic cosmic rays in the inner heliosphere, but its accuracy decreases towards the outer heliosphere. On the other hand, convection-diffusion approximation improves with radial distance. The reason for the complementary behavior of these two approximations is that energy losses are relatively important in the inner heliosphere, but not in the outer heliosphere. By a suitable choice of parameters the proposed model turns into two approximations: one close to "force - field" model (describing the energy losses of cosmic ray in the inner heliosphere) and "convection-diffusion" equation (giving the reduction of cosmic ray intensity in the outer heliosphere).
The modulated galactic cosmic ray differential spectra are compared with force-field approximation to the one-dimensional transport equation and with solutions of two-dimensional cosmic ray transport equation. Fitted parameters from the model equations are related to three 11-year solar cycles: 20, 22 and 23 through IMAX92 [1], CAPRICE94 [2], AMS98 [3, 4] and BESS [5, 6] experimental spectra for protons and alpha particles.
For measurement data, the calculation of the model parameters is performed by Levenberg-Marquardt algorithm, applied to the special case of least squares. Algorithm that combines the rapid local convergence of Newton-Raphson method with globally convergent method for non-linear systems of equations is applied for theoretically obtained differential spectra. The proposed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component.
REFERENCES
1. Menn, W. et al. The absolute flux of protons and helium at the top of the atmosphere using IMAX, Astrophys. J., 533, 281, 2000.
2. Boezio, M. et al., The cosmic ray proton and helium spectra between 0.4 and 200 GV, Astrophys. J, 518, 457, 1999.
3. Alcaraz, J. et al., Cosmic protons. AMS collaboration, Phys. Lett. B, 490, 27, 2000a.
4. Alcaraz, J. et al. Helium in near Earth orbit AMS collaboration, Phys. Lett. B, 494, 193, 2000b.
5. Shikaze, Y. et al. Measurements of 0.2 - 20 GeV/n cosmic-ray proton and helium spectra from 1997 through 2002 with the BESS spectrometer. Astropart. Phys., 28, 154, 2007.
6. Yamamoto, A. Precise measurement of low energy (< TeV) cosmic-rays with BESS. International Workshop on Energy Budget in the High Energy Universe, ICRR, Univ. Tokyo, Feb. 22-24, 2000.
7. Buchvarova M., P.I.Y. Velinov. Cosmic Ray Spectra in Planetary Atmospheres. Universal Heliophysical Processes. Proceedings IAU Symposium No. 257, 2008, Cambridge University Press, pp. 471 - 474, 2009.
8. Buchvarova M., P.I.Y. Velinov. Empirical Model of Cosmic Ray Spectrum in Energy Interval 1 MeV - 100 GeV During 11 - Year Solar Cycle. J. Adv. Space Res., 45, Issue 8, 1, 1026 - 1034, 2010.

In this work we develop a universal technique that improves all the medium-term prediction methods based on their monthly updating using the last observations of smoothed sunspot number. The improvement of prediction is provided by adaptive Kalman filter that uses last six monthly mean measurements of sunspot number. These last six monthly mean sunspot numbers are observed six months later than the 13-month running mean (start point for the prediction updating). As usual, last six monthly mean sunspot numbers are not directly used in prediction algorithm because of large level of noise included in them, although they give significant information about cycle evolution in future. The proper procedure of noise filtration and their direct using for the prediction provides the increase of prediction accuracy for all the methods.

The prediction results obtained by any medium-term method are inputted to the Kalman filter that causes improvement of these predictions and are used for construction of state space stochastic model. Noise statistics of this model is determined on the basis of the developed identification method.

Our technique has been tested on the three medium-term methods of predictions from 6 to 18 months ahead which are now in operation: McNish-Lincoln method (NGDC), standard method (SIDC), combined method (SIDC). Accuracy of prediction for McNish-Lincoln method is increased by 26-30%, for standard method by 14-24% and for combined method by 20-57%.

The mean energy W expended in a collision of a radiation with atmospheric gases is directly linked to its efficiency to ionise these gases. This value has been used extensively for fast computation of ion production rates in planetary upper atmospheres starting with Earth's. Computing this parameter in transport kinetic models with experimental uncertainties can tell us more about the number of processes that have to be taken into account and the intrinsic uncertainties of the models.
Simulations of W values using a family of multi-stream kinetic transport codes are presented for several atmospheric gases of planetology interest such as CO₂, CO, N₂, O₂, O, CH₄, H and He. For the first time cross sections uncertainties and their propagation in the models are consistently calculated using a Monte Carlo approach. Results for the complete thermospheres of Venus, Earth, Mars, Jupiter and Titan are shown for the first time. Differences between experimental and theoretical values of W for single gases show where improvements can be made in the measurements of inelastic cross sections by electron impact of e.g., CO₂, CO and O₂ molecules. A simple method is finally derived to calculate W of gas mixtures from single-component gases. This work is also a step towards the building of a reliable cross section database, AtMoCiaD, to be used in the context of future planetary missions such as ExoMars or MAVEN.

It is well known that in periods of great SEP fluxes of energetic particles can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead: according to NOAA Space Weather Scales are dangerous Solar Radiation Storms S5-extreme (flux level of particles with energy > 10 MeV more than 10^5), S4-severe (flux more than 10^4) and S3-strong (flux more than 10^3). In these periods is necessary to switch off some part of electronics for few hours to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 storms). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (few GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics (about 30-60 minutes later). We describe here principles and experience of automatically working of program "SEP-Search". The positive result which shows the exact beginning of SEP event on the Emilio Segre' Observatory (2025 m above sea level, Rc=10.8 GV), is determined now automatically by simultaneously increasing on 2.5 St. Dev. in two sections of neutron supermonitor. The next 1-min data the program "SEP-Search" uses for checking that the observed increase reflects the beginning of real great SEP or not. If yes, automatically starts to work on line the programs "SEP-Research". We determine also the probabilities of false and missed alerts. The work of NM on Mt. Hermon is supported by Israel (Tel Aviv University and ISA) – Italian (UNIRoma-Tre and IFSI-CNR) collaboration.

In report Dorman et al. (2010) was described how works automatically the program "SEP-Search", determined on the basis of on-line one-minute NM data the beginning of great SEP event. The next one-minute data the program "SEP-Search" uses for checking that the observed increase reflects the beginning of real great SEP or not. If yes, automatically starts to work on line the program "SEP-Research/Spectrum". We consider two variants: 1) quiet period (no change in cut-off rigidity), 2) disturbed period (characterized with possible changing of cut-off rigidity). We describe the method of determining of the spectrum of SEP in the 1-st variant (for this we need data for at least two components with different coupling functions). For the 2-nd variant we need data for at least three components with different coupling functions. We show that for these purposes can be used data of total intensity and some different multiplicities, but better to use data from two or three NM with different cut-off rigidities. We describe in details the algorithms of the program "SEP-Research/Spectrum". We show how worked this program on examples of some historical great SEP events. The work of NM on Mt. Hermon is supported by Israel (Tel Aviv University and ISA) – Italian (UNIRoma-Tre and IFSI-CNR) collaboration.

REFERENCES:
Dorman et al., "Great SEP events and space weather, 1. Probabilities of false and missed alerts", Report on ESSW-7

In report Dorman et al. (2010) was described how works automatically the program "SEP-Research/Spectrum", determined on the basis of on-line one-minute NM data the SEP spectrum on the Earth. We show that after this can be determined the time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP. We consider several possibilities: 1) one of these three parameters is unknown, 2) two of these three parameters are unknown, 3) all these three parameters are unknown. We show that in the first case is necessary to determine energy spectrum of SEP on the Earth in two different moments of time and from two equations automatically can be determined the unknown parameter (energy spectrum in source or diffusion coefficient, or time of ejection; determination is made from one equation, and other is used for control of used model). In the second case is necessary to determine energy spectrum of SEP on the Earth in three different moments of time and from three equations automatically can be determined two parameters (for example, the energy spectrum in source and diffusion coefficient in the interplanetary space). In the third case by using data for four different moments of time can be determined all three unknown parameters (time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP), and one equations can be used for control of model. We describe in details the algorithms of the programs "SEP-Research/Time of Ejection", "SEP-Research/Source" and "SEP-Research/Diffusion". We show how worked these programs on examples of some historical great SEP events.

REFERENCES Dorman et al., "Great SEP events and space weather , 2. Automatically determination of solar energetic particle spectrum.", Report on ESWW-7.

Ionospheric characteristics over Korea are studied using the parameters observed at Anyang site (37.390N, 126.950E). Since 1973, Radio Research Agency(here after RRA) which is a government agency in Korea has been observing ionospheric conditions over Korea. The current model for ionospheric observation is DPS-4 from UMLCAR. The data used for present study covers past three solar cycles, solar cycle 21, 22 and 23. Based on the ionospheric parameters observed during these solar cycle periods, statistical behavior of the ionosphere over the Korea and the relation between solar radio burst events and abnormal behaviors of the observed ionospheric parameters has studied. This paper shows the analysis result of the ionospheric variation over Korea and the relation between solar radio burst events and abnormal behaviors.

One key consideration for models of the SEPE environment is the distribution of SEPEs in time. Events in this respect are defined as enhancements of energetic particles above the background level as detected by monitors in Earth orbit (such as GOES/SEM and IMP-8/GME). These enhancements can include contributions from multiple physical phenomena (mainly CMEs with some contribution from solar flares) and are defined in such a way as to ensure consecutive enhancements are not linked in terms of their flux levels (e.g. particles from preceding CME may contaminate the interplanetary medium and be re-accelerated). It was previously assumed that in addition to mitigating these flux dependencies that it was possible to ensure that SEPEs were independent in time resulting in a random or Poissonian distribution of events. Our analysis of multiple event lists generated using markedly different event definitions shows that there remains a time dependecy which should be considered by future models of the SEPE environment. There appears to be not only a short-term system memory but also a longer-term memory with greater concentrations of events at some times and sparsity of events at other times than is described by a Poisson distribution which can better be modelled by a Lévy distribution. This research is one part of development of space environment modelling in the Solar Energetic Particle Environment Modelling (SEPEM) project.

Two models for the prediction of solar energetic proton (SEP) enhancements are presented. The models are based on a linear filter and on a special type of dynamic artificial neural network known as the layer-recurrent neural network. SEPs modelling has become of great interest in connection with safety of crews and protection of technological systems of spacecrafts outside the shielding Earth's magnetosphere. The models proposed are fed with information consisting of the class of X-ray flares originated close to the centre of the solar disc, types II or IV of the radio bursts, and of the position angles, widths, and linear speeds of the full or partial halo CMEs observed. The models are designed to provide forecasts of the fluxes of protons with the energies exceeding 10 MeV in the libration point L1.

The first direct measurements of HF-backscatter echoing electron density structures were conduced by the ICI-2 sounding rocket launched into the cusp ionosphere over Svalbard 5 December 2008. The echoing targets for coherent HF radars are 10-m scale electron density structures, half the operating radar wave length. Descending from ~300-200 km altitude ICI-2 traversed volumes of HF backscatter detected by the CUTLASS radar, near the poleward boundary of the active cusp. ICI-2 carried a novel 4-Needle Langmuir Probe system capable to measure absolute electron density at 5.7 kHz sampling rate which means sub-meter resolution along the trajectory. The payload was also equipped with a high resolution electron spectrometer to resolve fine scale structures in the cusp auroral precipitation, and it carried an electric field experiment to measure the plasma drift surrounding the space craft. The 10-m plasma irregularities were observed near the trailing edge of km scale gradients in the electron density, which is in favour of the gradient drift instability. The electron density gradients on which the gradient drift instability could operate were apparently modulated by the electron precipitation. Furthermore, plasma structuring also occurred near the centre of the inverted V electron beam, indicating that a current driven instability process also is to be considered. It is well known that ionospheric plasma density irregularities at scales from hundred of meters to a few kilometres affects GHz frequencies used for satellite communication and navigation systems. The TEC errors based on the ICI-2 electron density data has been simulated.

The multi-spacecraft Cluster mission has been launched in 2000 and is still providing lots of high-resolution and high-quality data in the Earth's plasmasphere. In particular, the plasma density can be determined by several instruments and methods. With the 4 spacecraft, it is also possible to compute reliable density gradients. Establishing plasmaspheric density profiles is useful for space weather studies. In particular, it can be used in empirical models and data assimilative modeling of the Earth's plasmasphere, which can be linked to ionospheric models. We highlight plasmaspheric density profiles and density gradients determined by Cluster, and how field-aligned profiles can be derived from that.

The model of possible influence of space weather on Earth wheat markets is described. The model is based on cause-sequence chain "space weather" -" earth weather" - "agriculture production-crop" - "price". In the frame of the proposed approach, sensitivity of earth markets to space weather state are not universal phenomena, realized in any time and in any phase, but require for realization specific necessary conditions caused by critical state of atmosphere, agriculture production and wheat market.

Although attempts have been made (particularly in the US) to produce ionospheric analyses and forecasts with global physical models, to date only a limited amount of work has been done to assimilate neutral atmosphere (thermosphere) data and fully coupled thermosphere-ionosphere assimilation and modelling systems have yet to emerge. Within the ATMOP (Advanced Thermosphere Modelling for Orbit Prediction) project, the Data Assimilation for Global Analysis workpackage aims to build capability for the assimilation of multiple observational data types to produce global analyses of the thermosphere and ionosphere that can initialize forecast simulations by a global, coupled thermosphere-ionosphere physical model with a longer term view to the development of future operational systems.

The first task within this workpackage will be to finalize the design and structure of the thermospheric data assimilation system, which will include decisions on length of the time-window for assimilation, the assimilation methods to be used, and selection of assimilation control variables. In the global assimilation system, control variables should be independent from each other and the probability density functions of their errors should ideally have Gaussian form. For this reason, meteorological forecasting systems choose to construct control variables such as streamfunction, velocity potential and ageostrophic pressure, rather than using observed temperature, winds or density directly. The second task of the workpackage is to produce an automated processing system for the observations that can be used in the assimilation system. The quality control system needs to check for gross errors and make further checks to ensure that the observations are acceptably close to forecast fields produced by the physical model, a step that might use observation errors supplied by the data providers. An estimate of model forecast error is also needed in order for the assimilation system to assess the relative weight it should assign to model forecast and observational data in the analysis. A test of the observation processing scheme will be to examine the performance of the physical model when perturbations (observation minus model differences) calculated by the scheme are added to the model fields.

As a preliminary activity, to explore the extent to which physical model forecast fields and observations might or might not be acceptably close, we have made a quantitative comparison of temperature retrievals for the middle atmosphere from two limb-sounding instruments, the Earth Observing System Microwave Limb Sounder (EOSMLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and forecast output over the 2007 spring equinox period from the Coupled Middle Atmosphere Thermosphere (CMAT2) model. Developed at University College London, CMAT2 is a global physical model which ranges upwards over 63 levels at intervals of 1/3 scale height in pressure from a lower boundary at 100hPa (15km altitude). Calculation of differences between collocated model and observed temperatures gives an indication of the scale of perturbation amplitudes that might be encountered by a future assimilation system.

In report Dorman et al. (2010) was described how works automatically the program allowed by using one minute data of NM for four different moments of time to determine the time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP . These results were obtained for high energy solar CR to which are sensitive NM. To expand obtained results in the region of small energies, now it is possible to use available from Internet on-line one minute data of satellites. We describe in details the algorithms of the programs "SEP-Research/Time of Ejection", "SEP-Research/Source" and "SEP-Research/Diffusion". We check obtain predictions on the basis of 30-40 minutes by data obtained during many hours after event beginning.

REFERENCES Dorman L. et al., "Great SEP events and space weather , 3. Automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum in source", Report on ESWW-7.

In report Dorman et al. (2010) were described how worked automatically the programs "SEP-Research/Time of Ejection", "SEP-Research/Source" and "SEP-Research/Diffusion" on the basis of NM and satellite data. On the basis of these programs on-line can be determined the time of ejection, diffusion coefficient in the interplanetary space and energy spectrum in source of SEP. Here we show how on the basis of these results can be made forecasting of expected radiation hazard for computers, electronics, solar battaries, technology and people health in space on different distances from the Sun and on different helio-latitudes. We show that the same can be made for satellites on different orbits in the magnetosphere with taking into account the change of cut-off rigidities along the orbits (for people health, solar battaries, computers, electronics, technology). By the method of coupling functions for different altitudes in the atmosphere we describe principles of radiation hazard forecasting on-line for air-planes on regular and non-regular lines in dependence of altitudes and cut-off rigidities, and value of shielding. On-line will be made forecasting of radiation hazard on the ground for people health and technology in dependence from the cut-off rigidity and atmospheric pressure. If for some cases the calculated radiation hazard will be expected higher than some definite level of dangerous, will be on-line send special Alerts. We show how worked these programs on examples of some historical great SEP events.

REFERENCES: Dorman L.I. et al. "Great SEP events and space weather, 4. Simultaneously using of NM and satellite one minute data", Report on ESWW-7.

The amount of thunderstorms (TS's) and electrified clouds in the Earth's troposphere generate currents into the global atmospheric electric circuit and maintain the electric potential of 250-300 kV of the ionosphere related to the surface. Between 50 and 100 lightning discharges per second over the globe produce electromagnetic (EM) fields in the Earth-ionosphere waveguide. Around a single thunderstorm strong quasi-electrostatic fields are generated, as drivers of transient luminous events (sprites and jets) in the strato/mesosphere and lower ionosphere. Experimental, as well as theoretical, investigations of the local and global interactions of the electric fields from lightning discharges with the earth environment are important for understanding the processes in the global electric circuit, and their possible role as a link between the space weather, on one hand and on the other, climate (e.g.Tinsley, 1996) and human health.

Possible mechanisms are discussed by which production of large electric fields is possible far from the source lightning discharge in the lower ionosphere, the mesosphere, and lower regions. These fields and the related currents can play an important role for the processes in the considered regions. According to some authors (Hale, 2002), the electric fields by a lightning discharge can lead to formation of transient fields in the magnetically conjugate (MC) region. These are realized by a polarization of the magnetosphere between both MC locations by electric charge inserted in the base of the ionosphere above the source TS. In situation when there are active TSs in both MC regions, a polarization wave can be created between the ends of the magnetic field lines across the magnetosphere. This mechanism is used to explain the large (>~1 V/m) electric fields measured in the mesosphere (Zadorozhny and Tyutin, 1997) which correlate with Carnegie curve and depend on the space weather parameters. Possibly, the production of a purple sprite after a lightning discharge in the MC region can be related to this mechanism. The alternative mechanism which involves fluxes of runaway electrons by the discharge and transported via magnetosphere is not supported experimentally.

These considerations show the need of evaluation of the electric fields generated by lightning in the MC region. Our goal is to perform such evaluation theoretically depending on different factors which include space weather, and solar and geomagnetic activity, since they influence the global electrical circuit. We estimate the role of the solar cycle on the electric fields of interest. We study the electric fields produced by a single cloud-to-ground lightning discharge in the region of the causative thunderstorm and in the MC region by simulation. The magnetosphere is represented as a media where no attenuation of the propagation takes place between two MC locations. Two approximations are used. First, we evaluate the electric fields of interest in quasi-static approximation, as solutions to the Maxwell’s equations for this case. The finite volume method is applied to solve the continuity equation for the density of the Maxwell current by assumption for a potential electric field. Also, more accurate study is implemented for the EM field by using the full system of Maxwell's equations. Finite-difference time-domain method (e.g. Simpson and Taflove, 2007) is used to calculate the propagation of the electromagnetic field. Perfectly absorbing boundary conditions are used on the lateral and the altitudinal boundaries. The model sub-domain for the source region has a horizontal dimension of 400 km; the vertical region is 0-150 km. For MC region the sub-domain is 1000 km horizontally and its vertical region is 50-150 km (the electric fields below 50 km are neglected). An adaptive grid and time-step are used to achieve an accuracy needed.

Our first results show that the electric fields of interest can be as large as few tenths of V/m in the mesosphere. However, in some specific cases, when the conductivity in the mesosphere is significantly reduced, they can be much larger. Another location of relatively large ELF fields generated far from the causative lightning discharge can be at the antipodal region. The contribution of these large EMF fields to the former considered electric fields can be also significant.

References

Hale L.C. (2002). Origin of big dc electric fields in the mesosphere, Adv. Space Res., 30, 2607.
Simpson, J.J., A. Taflove (2007). A review of progress of FDTD Maxwell’s equations modeling of impulsive subionospheric propagation below 300 kHz, IEEE Trans.Anten.Propag., 95, 1582.
Tinsley, B.A. (1996). Correlations of atmospheric dynamics with solar-wind induced changes of air-earth current density into cloud tops, J.Geoph.Res., 101, D23, 29,701.
Zadorozhny, A.M., A.A. Tyutin (1997). Universal diurnal variation of mesosphoric electric fields, Adv.Space Res. 20, 2177.

Current studies are devoted to temporal analysis of major plasma parameters in the topside ionosphere.

Statistical analysis are based on measurements onboard DEMETER satellite, one of satellites from CNES MYRIADE micro-satellite series. Analysed data were obtained with IAP - thermal plasma instrument and Langmuir probe - ISL. As there are now available more than five years of operational data, it gives good representation of topside ionospheric conditions, with possibility of carrying multi-instrumental analysis, performed in equal conditions. Measurements has been obtained during periods of both high Sun activity, as well as, calm conditions, what implies significant material for comparison and case-study analysis.

For better understanding ionosphere dynamics investigation is carried on ion drift, variations of electron and ion temperature and densities. We provide global characteristics of topside ionosphere for major plasma parameters. With obtained results, further studies on validation of common ionospheric models for upper ionosphere could be performed. Special interest is focused on seasonal variations, but additionally results of comparison studies for two distinct magnetic storms are presented. Events under investigation took place on January 2005 and August 2008.

During Solar flares, X-rays in the spectral range 0.1-0.8 nm penetrate the lower ionosphere, causing abrupt and strong enhancement of ionization (of one to three orders of magnitude with respect to regular values). These changes affect most remarkably the long wavelength propagation along the duct between the Earth surface and the lower reflective boundary of the ionospheric D-region (the Earth-ionosphere waveguide), making Very Low Frequency (VLF< 30 kHz) radio waves an excellent tool in exploring the lower ionosphere ionization.

We have registered Solar flares occurring during the Solar cycle 23 in particular, on the basis of signals from about half a dozen transmitters located at different sites of the globe, in Europe, Australia and USA, the respective VLF data, phase and amplitude, being continuously monitored by the AbsPAL facility and since 2009, also by another independent AWESOME receiver, both installed at the Institute of Physics, Belgrade (44.85 N, 20.38 E).

A model for predicting electron density enhancements in the lower ionosphere during X-ray Solar flares has been developed and successfully tested on about 150 Solar flare events in the period May to August 2004-2007. The model combines geostationary satellite GOES X-ray data and VLF wave data, both sets with 1 min resolution. In spite of the signals' different paths in length and structure, a distinctive coincidence between the disturbance of the VLF phase and amplitude, and the notable increase in X-ray irradiance is invariably encountered.

The phase and amplitude maximal disturbance (i.e. extremal value, either maximum or minimum) is most regularly seen to lag behind the maximum X-ray irradiance, thus bringing forward a characteristic time delay in correlating the ground based phase and amplitude measurements to the respective GOES X-ray measurements. The time delay could be uniquely determined for about 90% of observed events, and is a key input parameter to the model that solves the electron continuity equation with the electron production rate driven by the increased X-ray irradiance. The output is the time profile of the electron density, continuous throughout flare duration, for a given height.

However, at larger Solar flares, high class M and X in particular, we have observed amplitude disturbances which are highly structured and reveal a negative time delay if the concept is applied as defined. In this instance the increase of amplitude starts to follow the rising of the irradiance, but appears to be detained, reaching its apparent 'maximum' before the irradiance maximum, and then decreases through a characteristic 'bump' at the time the X-ray irradiance has descended from its maximum value. This pattern has been observed on long, sea dominated VLF paths, in particular on NAA/24.0 kHz, Maine to Belgrade , but also by others, like on NKL/24.8 kHz, Seattle to Dunedin path.

To comprehend this phenomenon we have compared the NAA signal registered by another VLF receiver, the one closest to Belgrade, at Erd (47.38 N, 18.92 E) with the distance difference along the GCP of 247 km. For flares that on the NAA to Belgrade path have induced amplitude detainment, no structured amplitude disturbance has been observed on NAA to Erd; a smooth amplitude maximum indicated regular time delay, instead. Electron density enhancements determined from the time delay on this path as well as on the paths GQD/ 21.0 kHz to Belgrade and to Erd have been found in fair overall agreement, the maximum discrepancies not exceeding 30%.

Alternatively, we have used the NOSC simulation programme LWPC (Long Wavelength Propagation Capability). By reproducing the measured amplitude and phase values, the Wait parameters, sharpness (β) and effective height (H') are determined at different stages of the flare, enabling to reproduce the corresponding electron density height profiles. Good agreement between the LWPC estimates and the results of the method based on time delay (within some 20 %) adds to the meaning of time delay as a quantity identifying the time of maximum waveguide perturbation.

Finally, by using the 'range exponential model' of the LWPC programme, the particular patterns of amplitude and phase disturbances have been analysed along the respective GCPs from transmitter to receiver. The redistribution of modal extrema on the propagation path is found to be decisive to the particular amplitude - phase perturbation. For a given flare event, electron density enhancements obtained by using the time delay method are comparable, whether deduced from the maximum or minimum, amplitude/ phase pattern, as displayed on different propagation paths.

The paper analyses the fast solar wind during solar cycle 23 and the geomagnetic storms driven by it in the terrestrial magnetosphere.
The authors' final goal consists in setting up a complex catalog of geomagnetic storms and their solar and heliospheric sources during the peculiar solar cycle no. 23 (1996-2008). Such catalog would offer a useful data base for case analysis in order to improve the geomagnetic forecasts.
Geomagnetic storms registered during solar cycle 23 were selected by their main parameters and features, such as: the start and maximum times, the intensity of storm (minimum of Dst), sudden or gradual commencement, the phase aspect. Their trigger sources (solar or heliospheric) were chosen from the high-speed streams catalog for solar cycle 23, the catalog of halo coronal mass ejections, the available solar flare data base, and OMNI II data base. The maximum value of the southern Bz during the main phase of the storm was also considered.
Comparative analysis of the storm intensity and their triggering factors marked out the complex role of the Bz for the energy transfer from solar wind to the terrestrial magnetosphere.

One of the challenges with EUV imagers like SDO/AIA is to rapidly retrieve pertinent physical information from the simultaneous observations of multiple wavelengths. As the number of wavelengths steadily increases, so do the difficulties encountered in visualising multispectral images.

The classical approach is to model the differential emission measure (DEM) and infer from it the temperature distribution for each image pixel. A different and empirical approach is blind source separation, where we assume that the for each wavelength, the pixel intensity is a linear combination of contributions (source images) with specific emission spectra. The objective then is to recover both the sources and their mixing coefficients without any a priori information. This is a blind source separation problem, which has recently received considerable attention in various areas such as the processing of hyperspectral images from planets, in acoustics, in airborne surveying, etc.

Here we consider a recent technique called Bayesian Positive Source Separation [Amblard et al., AA 487, L13-L16(2008)] to extract sources from SDO/AIA images in multiple wavelengths. In both cases we find that 3 source images capture the salient isolate specfic temperature bands corresponding to different parts of the corona. These results are validated through comparison with a DEM reconstruction based on a Bayesian model. We show how these source images can be used to reconstruct solar temperature maps in near real time.

Data gaps are a major nuisance in the analysis of space data and yet, surprisingly little effort has been spent to mitigate them. In most cases, linear of spline interpolation techniques are used, which are appropriate for short data gaps only.
Much better results can be achieved with multichannel measurements such as the solar spectral irradiance at different wavelengths or several solar proxies. The idea is to exploit the correlation between the different channels or variables to fill the gaps with common information. We consider for this the Singular Value Decomposition and show how arbitrarily large gaps can be filled.

Two examples are shown: one is about the solar CaK index, whose daily value records has over 60% of missing values. The second one is about the solar irradiance observations made by the SOHO/SEM instrument. Several months of observations were lost in 1998 when SOHO suffered from interruptions. We show how in both cases the missing values can be reconstructed with an error of less than 5%, relative to the solar cycle variability.

This paper examines the diurnal and seasonal variations of the height of the peak electron density of the F2-layer (hmF2) derived from digital ionosonde measurements at the low-middle latitude operating European station in Nicosia, Cyprus (coordinates: 35o N, 33o E geographic),. Median hourly values of hmF2 are obtained using manually scaled data during the solar minimum period from January 2009 to September 2010. Diurnal and seasonal variations of hmF2 are examined and comparisons of the observations are made with the predictions of the International Reference Ionosphere (IRI-2007) model.

In the present day society, there is a vital need for setting up education and outreach activities in the Space Weather field for creating a healthy environment for proper development of Space Weather markets along with fundamental and applied research activities.

The current "I LOVE MY SUN-3" event is based on the proposed COST ES0803 Working Group 3 (WG3) Action for "SG3.4 General public outreach to the non-specialist". It is an European outreach activity concerning space weather and the Sun as perceived by school children in the age group 7-11 years old. The main objectives of the "I LOVE MY SUN-3" are: