Fifth European Space Weather Week

 
Session: Poster Session 4 - Space Weather Models: from Research to Operations (10)
Type:
Date: Tuesday, November 18, 2008
Time: 16:00 - 19:00
Chair: D. Berghmans, ROB-SIDC; C. Mathison, UK Met Office
Co-chair:
Remarks: Posters will be on display all week.


Seq   Time   Title   Abs No
 
1   00:00   Modelisation of the Solar Activity with Volterra's Kernels Methods
Gaudeau, Claude1; Bremaud, Patrick1; Bobola, Phillipe1; Naji, Saad2
1BIOESPAS, FRANCE;
2BIOESPAS, MOROCCO

The statistical method is based on the study of the non-linear systems characterized by Volterra series, whose aim consists in the estimation of the Volterra nucleuses by the intermediary of the calculation of the cross-correlation functions.

In the first part, on one hand, we explain the essential properties linked to the junctional representation of the non-linear systems by Volterra series and, on the other hand, propose the statistical method.

In the second part, we apply this method to the identification of the sun spots generation process.

 
 
2   00:00   Ionospheric Plasma Turbulence as a Precursor of the Earthquake
Blecki, Jan1; Parrot, Michel2; Wronowski, Roman1
1Space Research Centre PAS, POLAND;
2LPCE/CNRS, FRANCE

The some strange behavior of the electromagnetic field around areas of the earthquakes as preseismic events can occur few hours or even few days before main shock. The payload of the DEMETER French microsatellite allows to measure waves and also some important plasma parameters (ion composition, electron density and temperature, energetic particles) with high temporal resolution in the regions over the seismic regions. In the present work analysis of the low frequency fluctuations of the magnetic and electric fields for the strong earthquakes with magnitude M> 6 will be given. Special attention will be given to study of the characteristics of the spectra of these variations and search of the nonlinear effects. This analysis is possible in the time interval when the waveform has been transmitted. The mechanism of the energy transmission from the earthquake to the ionosphere is not clear, but we can discuss the behavior of the ionospheric plasma and search of the instabilities which could be a source of the electromagnetic field variations. Some attempt of this discussion will be given in the presentation. The search of the characteristics of the spectra and multispectra and first results of the it will be given in this presentation.

 
 
3   00:00   Assessment of the Topside Sounder Model Profiler Performance
Kutiev, Ivan1; Marinov, Pencho2; Belehaki, Anna3; Reinisch, Bodo4; Jakowski, Norbert5; Mayer, Christopher5
1Geophysical Institute, Bulgarian Academy of Science, GREECE;
2Institute for Parallel Processing, Bulgarian Academy of Science, BULGARIA;
3National Observatory of Athens, GREECE;
4Center for Atmospheric Research, University of Massachusetts, Lowell, USA, UNITED STATES;
5Institute for Communication and Navigation, German Aerospace Center, GERMANY

In this investigation we apply a model-assisted technique to construct the topside electron density profile.This technique is based on the Topside Sounder Model (TSM), which provides the plasma scale height (Ts), O+-H+ transition height (Th), and their ratio Rt=Ts/Th, derived from topside sounder data of Alouette and ISIS satellites. The Topside Sounder Model Profiler (TSMP) incorporates TSM and uses the model quantities as anchor points for the construction of topside density (Ne) profiles. In the present version, TSMP takes the F2 peak characteristics -- foF2, hmF2, and the neutral scale height HmF2 at hmF2-- from ground-based Digisonde measurements. Previous investigations have demonstrated that HmF2, used in the Digisondes to construct the topside profiles, is smaller than the topside scale height extracted from topside sounder profiles, at middle latitudes. Therefore the Digisonde scale heights have to be adjusted by a factor estimated for each Digisonde location. When the Digisonde scale height is corrected by this factor, the reconstructed topside profiles are close to those provided by TSM. The new TSMP/Digisonde assisted technique of topside profile construction can improve the topside profiles from the worldwide network of Digisonde sounders. Extensive comparison and verification with ground and satellite derived TEC assesses the performance of the proposed technique A first indication from the comparison with CHAMP reconstructed profiles shows lower density of TSMP/Digisonde profiles between 400 km and 2000 km. Further comparisons with Vary-Chap profiles and RPI plasmagrams from the IMAGE satellite will lead to useful conclusions concerning the performance of the proposed method up to geosynchronous altitudes.

 
 
4   00:00   Plasma Sheet Evolution following Dual Lobe Reconnection
Amata, Ermanno1; Marcucci, Maria Federica2; Milillo, Anna2
1INAF, ITALY;
2INAF-IFSI, ITALY

When lobe reconnection occurs simultaneously tailward of the cusp at both hemispheres (dual lobe reconnection), magnetosheath plasma can be captured in the magnetosphere and results in a cold dense plasma sheet (CDPS). Here we study the evolution of the plasma sheet during a three days period when the IMF points steadily northward during two time intervals. For both intervals dual lobe reconnection is evidenced by means of ionospheric high latitude observations and Cluster measurements at the magnetopause. We apply the Orsini et al. (2004) method to LANL data in order to reconstruct the global equatorial proton distribution and evaluate the amount of particles injected into the near Earth region. We independently estimate the amount of particles captured in the magnetosphere through dual lobe reconnection by using SuperDARN and Image data. We find a good agreement between such two estimates.

 
 
5   00:00   The Observed and Modeled Low to Mid Latitude Thermospheric Response to Solar Wind Forcing from 2001 to 2006
Lathuillère, Chantal1; Menvielle, Michel2
1Laboratoire de Planétologie de Grenoble, FRANCE;
2CNRS/IPSL, FRANCE

Total thermospheric density retrieved from the STAR accelerometer measurements made onboard CHAMP since may 2001 is used to define a disturbance coefficient that characterize at low and mid latitudes the global thermospheric perturbation associated to Solar wind forcing. No projection of satellite data at a given altitude is performed, meaning that the disturbance coefficients do not depend on a priori hypothesis on the atmospheric scale height.

The statistical behavior of the disturbance coefficient is presented for high and for low solar activity conditions, and compared with several semi-empirical models. The observed and modeled behavior of the thermosphere during typical storms is also shown.

Our results are used to discuss the description of magnetic activity within the codes, and the possible use of new geomagnetic indices with different time or spatial resolution.

 
 
6   00:00   Predictive Statistical Models for Geo-effective Events
Srivastava, Nandita
Udaipur Solar Observatory, Udaipur, INDIA

Space weather prediction involves forecasting of the time of onset and magnitude of geomagnetic storms. Continuous datasets obtained from various space and ground observatories have led to systematic characterization of a large number of geo-effective events, which can also be used for statistical-model-based prediction of space weather. This paper documents and critically evaluates several such models for the prediction of the occurrence of intense to super-intense geomagnetic storms (DST < -100 nT). The models have been implemented using a series of solar and interplanetary variables that characterized major geo-effective events recorded during 1996-2008.

 
 
7   00:00   Modelling SEP Events within the SEPEM Project
Aran, Angels1; Jacobs, Carla2; Rodriguez-Gasen, Rosa1; Sanahuja, Blai1; Poedts, Stefaan2
1Departament d'Astronomia i Meteorologia, Universitat de Barcelona, SPAIN;
2Centrum voor Plasma-Astrofysica, K.U. Leuven, BELGIUM

The Solar Energetic Particle Environment Modelling (SEPEM) ESA project aims to create engineering models and tools to address current and future needs derived from the space weather effects produced by solar energetic particle (SEP) events in the inner heliosphere. Particularly, one of the ultimate goals we are pursuing is to obtain a new tool that can give account of the helio-radial and longitudinal dependences of SEP particle fluxes by predicting the particle event intensity-time profiles using a physics-based model. For this, we are working to improve the shock-and-particle model developed by Lario et al. (1998).

We present an example of the modelling of SEP events using a combined model that describes both the simulation of the propagation of the CME-driven forward shock and the particle transport of the shock-accelerated particles along the interplanetary magnetic field line connecting the shock front with the observer. We use a 2D MHD model for the simulation of the shock evolution from 3 solar radii to beyond the Mars orbit and the particle transport model developed by Lario et al. (1998) to reproduce the proton intensities (and first order anisotropies whenever possible) observed during actual SEP events. We derive the evolution of the injection rate of shock-accelerated particles, Q, and the particle transport parameters. We present here the resulting modelling and discuss on the empirical relation between Q and the plasma speed jump across the shock, VR.

Reference: Lario, D., Sanahuja, B. and Heras, A.M., Astrophysical J., 509, 415-435 (1998).

 
 
8   00:00   Space weather events in July 1982 and October 2003 including effects of geomagnetically induced currents in Sweden
Wik, Magnus1; Pirjola, Risto2; Lundstedt, Henrik1; Viljanen, Ari2; Wintoft, Peter1; Pulkkinen, Antti3
1Swedish Institute of Space Physics, SWEDEN;
2Finnish Meteorological Institute, FINLAND;
3NASA Goddard Space Flight Center, UNITED STATES

"Space Weather" phenomena, originating from the activity of the Sun, may produce problems to technological systems in space and at the Earth's surface. "Geomagnetically induced currents" (GIC) flowing in technological networks, such as power networks, pipelines, communication cables and railways, constitute the ground end of the space weather chain. In particular, Swedish systems have experienced many GIC problems in the past, one important reason for which is the high-latitude location of the country.

In this study, we have analysed two famous GIC events in Sweden: a railway signal malfunction on July 13-14, 1982, and a power blackout on October 30, 2003 Both occurred during very intensive space weather storms and each of them a few years after the sunspot maximum. A detailed description of the conditions on the Sun and in the solar wind and of the two GIC events is given.

By applying modelling techniques introduced and developed earlier, we calculated the horizontal geoelectric field at the Earths surface in southern Sweden during the two storms. We also computed GIC flowing in the southern Swedish 400 kV power network for the October 2003 event. All modelling results agree well with available measured data. The geoelectric field reached values of several volts per kilometre in the July 1982 storm and was somewhat smaller in the October 2003 storm. However, GIC of some hundreds of amperes flowed in the power system during the October 2003 event. We also give technical information about the effects on the railway equipment and power system equipment.

 
 
9   00:00   Global Atmospheric Electric Circuit Response to Lightning Discharges - A Theoretical Study
Velinov, Peter; Tonev, Peter
Solar-Terrestrial Influences Laboratory, BAS, BULGARIA

The thunderstorms and electrified clouds over the Earth generate the electric currents and fields in the remote fair-weather regions through the global atmospheric electric circuit (GEC), by which the ionosphere-ground current of 1-6 pA.m-2 is maintained, with an average 2 pA.m-2. The related electric fields in the fair-weather regions are of the order of 100 V/m at sea level. These electric currents and fields show periodic variations on different time-scales: the diurnal and larger.

According to a series of works, considerable changes in weather and climate characteristics can take place due to long-term variations of these currents and fields, provoked through solar activity changes (e.g. Rycroft et al., 2000; Tinsley et al., 2007). The solar wind can affect the ionosphere-ground fair-weather electric current by different ways: by modulation of the galactic ray flux, which is responsible for the conductivity in the lower stratosphere and upper troposphere; by changes in the precipitation of relativistic electrons; and by variations of the ionospheric potential in the polar caps. Long-term variations of the fair-weather electric currents in the troposphere related to the solar cycle thus presumably take place. These can play an important role at the tops of the clouds (e.g. Tinsley et al., 2007) as a factor in the processes of nucleation there. With respect to these features, the fair-weather electric field in the troposphere, as well as their transients caused by strong lightning discharges, are theoretically estimated in our work. Approximate estimations are obtained by simulation based on the Maxwells equations under quasi-static conditions. Our results show that the electric field transients in the troposphere due to remote separate lightning discharges are rather small and probably cannot play a significant role in the nucleation processes.

Another region of our interest is the mesosphere, where large quasi-static electric fields of the order of 1 V/m (and even much more, in specific cases) have been often observed at altitudes of about 60-65 km (e.g. Zadorozhny and Tyutin, 1998). At high and high-middle latitudes these electric fields are considerably correlated with the geomagnetic activity. These electric fields presumably can play an important role in the mesospheric chemical processes - this problem can be a subject of further investigations. Some authors (e.g. Hale, 2005) consider the large mesospheric fields revealed as a response of the global electric circuit to remote strong lightning discharges, with an account of the influence of the geomagnetic field.

With respect to the phenomenon considered, we study theoretically the electric field transients in the mesosphere created by a strong remote lightning discharge. For this goal, we propose a simplified global-scale numerical model of the electromagnetic response of the global electric circuit, which is based on the system of Maxwell's equations. Our first results show that the electric field transients of interest show significant dependence on variations of the mesospheric conductivity, which are caused by the geomagnetic activity. On the other hand, the geometry of the geomagnetic field shows a strong influence to the electric field transients: these are much larger in points located in field-aligned direction from the lightning discharge, than in a transverse direction, as related to the geomagnetic field. The considerable role of the local orientation of the geomagnetic field on the DC electric field distributions above a thundercloud has been theoretically predicted earlier, e.g. by Tonev and Velinov (2002).

References

Hale L.C. (2005). Origin of big DC electric fields in the mesosphere, Adv.Space Res., 35, 1455-1460.
Rycroft M.J., Israelsson S., and Price C. (2000). The global atmospheric electric circuit, solar activity and climate change, J.Atmos. Sol.-Terr. Phys., 62, 1563-1576.
Tinsley, A.B., G.B.Burns, and L.Zhou (2007). The role of the global electric circuit in solar and internal forcing of clouds and climate, Adv.Space Res., 40, 1126.
Tonev P.T., and Velinov, P.I.Y. (2002). Electrostatic fields above thunderclouds at different latitudes and their ionospheric effects, Adv. Space Res., 30, 2625-2630.
Zadorozhny A.M. and A. A. Tyutin (1998). Effects of geomagnetic activity on the mesospheric electric fields, Ann. Geophysicae, 16, 1544-1551.

 
 
10   00:00   A Model for Short-Term Warnings of Solar Energetic Proton Events
Laurenza, Monica1; Cliver, Edward W.2; Storini, Marisa3; Ling, Alan4
1IFSI-ROMA/INAF, ITALY;
2AFRL, Space Vehicles Directorate, Hanscom AFB, MA, USA, UNITED STATES;
3IFSI-Roma/INAF, ITALY;
4Atmospheric Environmental Research, Inc. Lexington, MA, USA., UNITED STATES

We have developed a model to provide short-term warnings of solar energetic proton (SEP) events that meet or exceed the Space Weather Prediction Center (SWPC/NOAA, USA) threshold of J(> 10 MeV) = 10 pfu. The method is based on several solar activity parameters (flare location, soft X-ray fluence, type III radio fluence), which were collected for the period 1995-2005. Details on the used parameters and metodology are described together with the reliability of the obtained results for warnings issued 10 minutes after the maximum of each soft X-ray flare of class ≥ M2.

 
 
11   00:00   Solar CRs from 20.01.2005 and their Influence on Ozone, Temperature and Air Pressure in the Middle Atmosphere
Velinov, Peter1; Tassev, Yordan1; Eroshenko, Evgenia2; Mateev, Lachezar1; Tomova, Dimitrinka3; Mishev, Alexander4
1Solar-Terrestrial Influences Laboratory, BAS, BULGARIA;
2IZMIRAN, Moscow, RUSSIAN FEDERATION;
3Sofia University, BULGARIA;
4INRNE BAS, BULGARIA

The present study investigates the changes in the profiles of the ozone (O3) mixing ratio, temperature (T) and atmospheric pressure (P) during and immediately after the solar Cosmic Ray (CR) penetration on 20 January 2005. Analysis is based on the data from Microwave Limb Sounder (MLS) on board the AURA satellite and the geostationary satellite GEOS 11. MLS data for O3, T and P profiles are taken at 50 N degree. In order to reduce the influence of solar UV radiation on the proton effects estimation, a night time measurements are analyzed only. Six energy intervals for proton fluxes measured on GOES 11 have been selected and their effect on the ozone mixing ratio, temperature and pressure at different atmospheric levels is analyzed. It is shown that the maxim cross-correlation coefficient (+0.68) between the ozone and proton fluxes is obtained at 30.9 km for the lowest energetic interval of proton fluxes (i.e. E = 0.8 - 4 MeV). The profiles of the stratospheric ozone in the investigated period (15-28 January 2005) are calculated and the variations of the ozone density due to solar CR effect and geomagnetic disturbances are studied. A new model for the computation of the ozone production rate (mol.cm-3.s-1) by high-energy and relativistic particles is applied. Comparisons between experimental and theoretical ozone variations are made. On the basis of this analysis an interpretation of possible mechanisms of the stratospheric ozone response on solar CR is proposed.

We analysed the atmospheric response within the longitudinal interval 0.20 - 40 E, what is exactly 190 night time profiles of O3, T and P for the whole examined period. The differential proton flux has been taken from the GOES 11 satellite into six energy intervals (E=0.8 - 4 MeV, E=9 - 15 MeV, E=15 - 40 MeV, E=40 - 80 MeV, E=80 - 165 MeV, E=165 - 500 MeV). The protons flux data are synchronised with the data for ozone, temperature and pressure by UT. O3, T and P measurements at each altitude are compared and statistically analysed with all energetic intervals of precipitating protons, which allow us to estimate the effect of each part of the differential spectrum of proton fluxes on ozone, temperature and pressure. Thereby, as a result of combining the seven ozone data series with the six energy intervals of the protons, forty two pairs of time series have to be statistically analyzed.

We apply the cross-correlation analysis on different combination of time series. It is a common method to detect existence of linear correlation between data records, even if manifested with some delay. The most of our study is concentrated on looking for a relation between proton fluxes and O3, T and P profiles as well as on time delay of their response. In this case proton fluxes were chosen as a factor of influence while ozone, temperature and pressure were lagged relative to them. In such a way the time shift between the initial forcing (intense proton fluxes) and atmospheric response via changes in O3, T and P profiles can be determined. The statistical significance of the maximal cross-correlation coefficient was checked by Fisher's Z-transformation. The results obtained from the statistical analysis performed are presented in four tables. Each of them shows the maximum cross-correlation coefficients of the solar protons flux with the ozone (Table 1), solar protons flux with the temperature (Table 2) and solar protons flux with the atmospheric pressure (Table 3). Table 4 presents the maximum cross-correlation coefficients between the ozone and temperature, ozone and atmospheric pressure, and the temperature and atmospheric pressure with different running median smoothing on 6, 11 and 20 points of data series.

A new analytical and numerical approach for penetration and ionization of cosmic ray nuclei with charge Z in the planetary ionospheres and atmospheres is created . The electron production rates are calculated using new formulas, which couple the five main energy intervals in the ionization losses function (dE/dh). The geomagnetic cut-off rigidities and the energy decrease laws for the different intervals are used for creation of an intermediate transition energy region, which performs the coupling of the five main intervals in the ionization losses function. The ionization profiles are computed for two major solar proton events - namely for GLE05 from 23 February 1956 and for GLE69 from 20 January 2005. The assumed geomagnetic cut-off rigidity is RC=2.3 GV. The full 3D integration with introduction of the Chapman function can then be done which will provide higher accuracy of the electron production rate model. The computational results are in accordance with experimental data. The Pfotzer maximum of the electron production rate is obtained by the computational procedure.

References

P. Velinov, Y. Tassev, E. Eroshenko, L. Mateev, D. Tomova. Report C23-0037-08 at the 37 COSPAR Scientific Assembly, Symposium C23, July 13-20, Montreal, Canada.

 
 
12   00:00   On the Relationship between Solar Wind Parameters and Dst Index in Quiet Time
Cerrato, Yolanda; Saiz, Elena; Cid, Consuelo
Universidad de Alcala, SPAIN

Studies devoted to solar wind - magnetosphere interaction manage long data periods undiscriminating quiet or stormy time. In this work we have studied the relationship between interplanetary dawn-dusk electric field and solar wind dynamic pressure with Dst index for extraordinary quiet time periods which covers two last solar minima. Preliminary results indicate that Dst index can be obtained as a superposition of a function of solar wind dynamic pressure and a linear function of dawn-dusk electric field. A delay and smoothness in the response of the magnetosphere to interplanetary electric field is also appreciated.

 
 
13   00:00   Frequency Models for Connection of Satellite Anomalies with Space Weather
Dorman , Lev for INTAS team
Tel Aviv University and Israel Space Agency, ISRAEL

Results of the EU INTAS Project 00810, which aims to improve the methods of safeguarding satellites in the Earth's magnetosphere from the negative effects of the space environment, are presented. Anomaly data from the "Kosmos" series satellites in the period 1971-1999 are combined in one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of the space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluencies of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high ( 5000 events) and low (about 800 events) altitude orbit satellites. No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in a behavior. Satellites were divided on several groups according to the orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits that should be taken into account under developing of the anomaly frequency models. This research is partly supported by COST, INTAS and NMDB Projects.

Keywords: Frequency models, Space weather; Satellite anomalies; Energetic particles; Magnetic storms

INTAS Team:
N. Iucci (a), L.I. Dorman (b,c,*), A.E. Levitin (c), A.V. Belov (c), E.A. Eroshenko (c), N.G. Ptitsyna (d), G. Villoresi (a), G.V. Chizhenkov (c), L.I. Gromova (c), M. Parisi (a), M.I. Tyasto (d), V.G. Yanke (c)

(a) Dipartimento di Fisica "E. Amaldi", Roma-Tre University, Rome, Italy
(b) Israel Cosmic Ray and Space Weather Center and Emilio Segre_ Observatory, Affiliated to Tel Aviv University, Technion and Israel Space Agency, PO Box 2217, Qazrin 12900, Israel
(c) IZMIRAN, Russian Academy of Science, Troitsk, Russia
(d) SPb FIZMIRAN, Russian Academy of Science, St. Petersburg, Russia
*Corresponding author: Lev I. Dorman, Tel.: +972-4-6964932; fax: +972-4-6964952. E-mail address: lid@physics.technion.ac.il.

 
 
14   00:00   The Model Forecasting of Great Magnetic Storms Accompanied with Forbush Effects by CR One-hour Network Data
Dorman, Lev
Tel Aviv University and Israel Space Agency, ISRAEL

According to NOAA Space Weather Scales, geomagnetic storms of scales G5 (3-hour index of geomagnetic activity Kp=9), G4 (Kp=8) and G3 (Kp=7) are dangerous for people technology and health (influence on power systems, on spacecraft operations, on HF radio-communications and others). To prevent these serious damages will be very important to forecast dangerous geomagnetic storms. In many papers it was shown that in principle for this forecasting can be used data on CR intensity and CR anisotropy changing before SC of major geomagnetic storms accompanied by sufficient Forbush-decreases. In this paper we consider over 100 major geomagnetic storms and for each case we analyze hourly data of many NM for 8 days with SC in the 4-st day of 8-days period (so before SC we have at least 3 full days). We determine what part of major geomagnetic storms is accompanied CR intensity and CR anisotropy changing before SC, and what part of major geomagnetic storms does not show any features what can be used for forecasting. We estimate also how these parts depend from the index of geomagnetic activity Kp.

We present developing of methods for forecasting on the basis of neutron monitor hourly on-line data (as well as on-line muon telescopes hourly data from different directions) geomagnetic storms of scales G5 (3-hour index of geomagnetic activity Kp=9), G4 (Kp=8) and G3 (Kp=7) (according to NOAA Space Weather Scales). These geomagnetic storms are dangerous for people technology and health (influence on power systems, on spacecraft operations, on HF radio-communications and others). We show that for especially dangerous geomagnetic storms can be used global-spectrographic method if on-line will be available 35-40 NM and muon telescopes. In this case for each hour can be determined CR anisotropy vector, and the specifically behavior of this vector before SC of geomagnetic storms G5, G4 or G3 (according to NOAA Space Weather Scales) can be used as important factor for forecast. The second factor what can be used for SC forecast is specifically behavior of CR density (CR intensity) for about 30-15 hours before SC (caused mainly by galactic CR particles acceleration during interaction with shock wave moved from the Sun). The third factor is effect of cosmic ray pre-decreasing, caused by magnetic connection of the Earth with the region behind the shock wave. We demonstrate developing methods on several examples of major geomagnetic storms. This research is partly supported by COST, NMDB and INTAS Projects.

 
 
15   00:00This splinter meeting is meant to be a discussion forum focused on the significance of indices and proxies presently in use, and on the adoption of new ones in view of a more comprehensive quantitative description of Space Weather phenomena, capable of improving both modeling and prediction operational frameworks.This splinter meeting is meant to be a discussion forum focused on the significance of indices and proxies presently in use, and on the adoption of new ones in view of a more comprehensive quantitative description of Space Weather phenomena, capable of improving both modeling and prediction operational frameworks.   Parametric Study of Breakout Coronal Mass Ejections in the Solar Wind
Soenen, Alexander1; Poedts, Stefaan1; Jacobs, Carla1; van der Holst, Bart2
1Centre for Plasma-Astrophysics, K. U. Leuven, BELGIUM;
2Space Research Laboratory, University of Michigan, UNITED STATES

We present the results of a parametric study on the initiation and evolution of Coronal Mass Ejections (CMEs) studied by means of the breakout model embedded in a 2.5D axisymmetric solar wind in the framework of numerical magnetohydrodynamics (MHD). The initial results used for this parametric study were published by B. van der Holst et al. (2007). In this paper they describe how the initial, steady equilibrium containing a pre-eruptive region consisting of three arcades with alternating magnetic fl ux polarity and correspondingly three neutral lines on the photosphere can produce a CME by shearing part of this arcade. They conclude that the breakout CME propagation through the solar wind consists of two major phases. The original breakout model phase that closely follows the scenario described by Antiochos et al. (1999). However, at a certain moment the breakout reconnection, on the leading edge of the rising central arcade and a flare reconnection below, stops and two new reconnection spots are formed on the flanks of the erupting central arcade. These ultimately disconnect the top of the overlying helmet streamer from the Sun. We investigate the infl uence of the field strength and arcade size on the CME velocity and look at the effect of changing the sheartime or shear velocity The effect of the solar wind on these simulations is also investigated as promised. The results of changes to these parameters are This splinter meeting is meant to be a discussion forum focused on the significance of indices and proxies presently in use, and on the adoption of new ones in view of a more comprehensive quantitative description of Space Weather phenomena, capable of improving both modeling and prediction operational frameworks. analyzed by looking at properties like current density, relative density, kinetic and magnetic energy, and helicity.

 
 
16   00:00   Study on Solar Sources and their Effects on Ionosphere and Geomagnetic Field
Perrone, Loredana1; Parisi, Mario2; Meloni, Antonio1; Damasso, Mario2; Galliani, Marco2; Zolesi, Bruno1
1Istituto Nazionale di Geofisica e Vulcanologia, ITALY;
2Universita' degli Studi di Roma Tre, ITALY

Particularly intense events on the Sun occurred during cycle 23. We investigated the characteristics of these events and 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.

 
 
17   00:00   Radiation Exposure Measurements at Aviation Altitudes during the Past Solar Minimum
Meier, Matthias M.; Hubiak, Melina; Matthiä, Daniel; Wirtz, Michael
DLR, GERMANY

The radiation exposure at aviation altitudes is the result of cosmic rays generated by interactions of primary high-energetic particles of cosmic origin with atoms in upper layers of the Earth's atmosphere. The intensity of the corresponding radiation field, which aircrew members are exposed to, depends on altitude, geomagnetic latitude and solar activity varying within an 11-year cycle the minimum of which corresponds to the highest radiation exposure.

The dose monitoring and recording of radiation exposure for crew members have been obligatory in Germany since legislation based on the EU Directive 96/29/EURATOM became effective. The corresponding EU directive stipulates basic standards for the radiation protection of aircrews that are regarded as radiation workers due to their exposure to cosmic rays.

Radiation exposure is generally estimated with computer programs for operational purposes. During the past solar minimum DLR performed several measuring flights in order to verify the corresponding dose calculations using a TEPC (tissue equivalent proportional counter), various types of MDU-Liulin (mobile dosimetry unit) semiconductor detectors, as well as several Bubble Detectors. First results of this investigation will be presented.

 
 
18   00:00   Properties of Traveling Atmospheric Disturbances (TADs) Inferred from Accelerometer Observations
Bruinsma, Sean1; Forbes, Jeffrey2
1CNES, FRANCE;
2Department of Aerospace Engineering Sciences, University of Colorado, UNITED STATES

The accelerometers on the CHAMP and GRACE satellites have made it possible to accumulate near-continuous records of thermosphere density between about 370 and 490 km since May 2001, and July 2002, respectively. They have recorded the response to virtually every significant geomagnetic storm during this period. CHAMP and GRACE are in (near) polar and quasi-circular orbits, sampling 24 hr local time approximately every 4 and 5 months, respectively. These capabilities offer unique opportunities to study the temporal and latitudinal responses of the thermosphere to geomagnetic disturbances.

Data from initially 34 geomagnetic storms were explored, but significant and unambiguous TAD activity in the observed response of the thermosphere was detected for about half the events. The atmospheric variability is evaluated by de-trending the data, allowing the extraction of specific ranges in horizontal scale, and analyzing density "residuals". The scale of the perturbation is decisive for its lifetime and relative amplitude. Sometimes the disturbances represent wave-like structures propagating far from the source, and these so-called 'TADs' were detected and described for the May 2003 storm for the first time. Some TADs traveled over the pole into the opposite hemisphere; this was found in both CHAMP and GRACE data. Most TADs propagate equatorward, but poleward propagating TADs have on occasion been detected too. The estimated speeds of the observed TADs are of the order of 300-1000 m/s, 650 m/s on average, and their mean scale is approximately 2000 km. The TADs observed with GRACE are significantly slower than those seen in the CHAMP data. The opposite is expected from theory: speed increasing with altitude.

 
 
19   00:00   Pre-storm NmF2 Enhancements at Middle Latitudes - Delusion or Reality
Mikhaylov, Andrey1; Perrone, Loredana2
1Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN), Russian Academy, RUSSIAN FEDERATION;
2Istituto Nazionale di Geofisica e Vulcanologia, ITALY

A critical analysis of recent publications devoted to the NmF2 pre-storm enhancements is made. There are no convincing arguments that the observed cases of NmF2 pre-storm enhancements at middle and sub-auroral latitudes considered by other researchers bear a relation to the following magnetic storms In all cases considered either the NmF2 enhancements were due to moderate auroral activity or similar NmF2 enhancements took place during some previous days presenting the class of positive quiet time (Q-disturbance) events Therefore, tentatively it is possible to conclude - there is no such an effect as the pre-storm NmF2 enhancement as a phenomenon inalienably related to the following magnetic storm to say nothing of using such NmF2 enhancements as precursors for the geomagnetic storms. The formation mechanisms of some types of NmF2 positive disturbances are discussed. The dayside cusp is considered as a channel for the F2-layer positive Q-disturbances formation

 
 
20   00:00   Intercontinental Assessment of GIC: Measure the Magnetic Field in Europe, Estimate GIC in Canada
Viljanen, Ari1; Pirjola, Risto1; Ketola, Anneli1; Shelemy, Steve2; Reske, Dean2; Mann, Ian3; Ferguson, Ian4; Boteler, David5
1Finnish Meteorological Institute, FINLAND;
2Manitoba Hydro, CANADA;
3University of Alberta, CANADA;
4University of Manitoba, CANADA;
5Natural Resources Canada, CANADA

Modelling of geomagnetically induced currents (GIC) has been traditionally based on the measured geomagnetic field from the area of a specific technological conductor system. However, we may expect that geomagnetic variations are statistically similar at the same magnetic latitudes. We have applied this idea in the study assessing GIC in the Manitoba Hydro power system in Canada. The magnetic data are provided by the IMAGE magnetometer network operating in the northern Europe at magnetic latitudes 54-75 deg N. The time span covers the full sunspot cycle 1996-2006 with a 10-s time resolution. The project provides three main products: 1) statistics of the time derivative of the magnetic field (dB/dt), which is a handy proxy of the GIC activity, 2) statistics of the modelled geoelectric field, which is the driver of GIC, 3) statistics of the modelled GIC in a specific configuration of the Manitoba power system. The extreme characteristics of the 29-30 October 2003 storm become prominent also in this investigation.

 
 
21   00:00   Studies of geomagnetically induced currents (GIC) in electric power transmission networks in China
Pirjola, Risto1; Liu, Lian-guang2; Liu, Chun-ming2; Pirjola, Risto1; Zhang, Bing2
1Finnish Meteorological Institute, FINLAND;
2North China Electric Power University, Beijing, China, CHINA

Geomagnetically induced currents (GIC) flowing in technological networks at the Earth's surface are ground effects of space weather. They are driven by the geoelectric field induced by time variations of the geomagnetic field The largest geoelectric fields and so also the highest GIC values would be expected to occur at high latitudes, at which geomagnetic variations are most intense. However, the geoelectric field is also much affected by the ground conductivity distribution. Furthermore, GIC magnitudes do not only depend on space physical and geophysical factors but the resistances and configuration of the network considered are also important. This explains why large GIC with effects on transformers have been observed in electric power networks in China, which is a mid-to-low-latitude country. The largest GIC recorded in China so far is 55.8 A at a high-voltage (= 500 kV) transformer neutral at a nuclear power plant on November 9, 2004. Modelling results based on the "plane wave assumption" agree well with measured GIC data. However, the particular nuclear power plant is located at the ocean coast, which generally decreases the validity of the "plane wave assumption". The "coast effect" obviously increases geoelectric fields in the vicinity of the plant, thus enhancing GIC values. This means that the modelling should be developed further. New super-high-voltage (= 750 kV) and ultra-high-voltage (= 1000 kV) power networks are being planned in China. Because a higher voltage level implies smaller resistances of transmission lines GIC continue to be a subject necessary to be investigated carefully in China. The importance of GIC is additionally emphasised by the large geographical sizes of power networks in China. In this paper, we describe the measurements and studies of GIC performed in Chinese power networks so far and outline future plans from the point of view of GIC.

 
 
22   00:00   Modeling the Different Stages of the Recovery Phase of Intense Geomagnetic Storms
Aguado, Jesus; Cid, Consuelo; Saiz, Elena; Cerrato, Yolanda
Universidad de Alcalá, SPAIN

The geomagnetic index Dst is an indicator of the enhancement of the ring current and other currents during a geomagnetic storm. The minimum value of Dst is used as indicator of the intensity of the storm. After reaching this value, the index Dst recovers coming back to the value of the quiet time. During this recovery phase several physical losses processes are involved, such as charge-exchange, Coulomb scattering and wave-particle interaction.

During the recovery phase of intense geomagnetic storms the Dst index shows a two-phase decay, which could be related to the involved losses mechanisms.

In this work we analyze the intense geomagnetic storms included in the period between the years 1960 to 2003 and we look for a model which will reproduce the stages of recovery phase in the frame of the losses mechanisms involved

 
 
23   00:00   Space Weather Models: Some of the Turkish Forecast Models and Results from the IHY Year 2007
Tulunay, Y.; Tulunay, E.
METU / ODTU, TURKEY

Near-Earth This splinter meeting is meant to be a discussion forum focused on the significance of indices and proxies presently in use, and on the adoption of new ones in view of a more comprehensive quantitative description of Space Weather phenomena, capable of improving both modeling and prediction operational frameworks.space processes are in general non-linear and time varying. In such cases data driven models are shown to be promising. Since 1990, a small group at METU, Ankara has been working on data driven generic models of NEAR EARTH SPACE (NES) processes. There have been five EU COST activities, COST 238; 251; 271; 724; 296 (IHY), and the FP6: SWEETS (Space Weather and Europe → an Educational Tool with the Sun)

In this work, some examples of services affected by space weather phenomena, are given first. Then some case studies are presented briefly to demonstrate the capability of the models developed by the authors and their group, eg. Neural Network, Fuzzy Neural Networks, Cascade Modeling and mapping, etc. As a case study, a Fuzzy-Neural Network approach is employed for forecasting during one of the major storms, Halloween 2003 storm. Since the location of ionosondes are fixed, there are distinct points for measurement. Several attempts were done for instantaneous mapping foF2. In addition, the coupling with Fuzzy NN, a Genetic Programming approach is employed for the generation of a general mapping function for forecast mapping of foF2.

 
 
24   00:00   Operational Validation of HAFv2 Model's Predictions of Shock Arrivals at Earth and the Influence of CMEs
Smith, Z.K.1; Dryer, M.2; McKenna-Lawlor, S.M.P.3; Fry, C.D.4; Deehr, C.S.5; Sun, W.5
1NOAA / Space Weather Prediction Center, UNITED STATES;
2NOAA / Space Weather Prediction Center, Exploration Physics International Inc., UNITED STATES;
3Space Technology Ireland, National University Ireland, IRELAND;
4Exploration Physics International, Inc., UNITED STATES;
5Geophysical Institute, University of Alaska, UNITED STATES

The Hakamada-Akasofu-Fry version 2 (HAFv2) model has been used to predict, in the operational environment, the arrival of interplanetary shocks at Earth. The prediction of shock arrivals is important in Space Weather applications because these events cause Sudden Impulses (SIs) that are often followed by geomagnetic disturbances that disrupt human technologies. The HAFv2 uses, for input, a background solar wind onto which transient events are superimposed. The background solar wind computations are continuously updated based on the solar magnetic field measurements. Interplanetary shocks (transient events) are superimposed on this background whenever observations are reported near-real-time of a metric type II radio burst and/or a halo or partial halo CME. Supporting inputs, obtained from the GOES 1-8 Å X-ray data and images of the Sun (Hα, EUV, etc.), give the duration and location of the source. This study is the third in a series that now covers Solar Cycle 23. The first covered the rise phase, from February 1997 to October 2000. The second study covered the maximum phase, November 2000- August 2002. This study covers the declining phase through December 2006, the approximate time when this model was transferred to U.S. Air Force Weather Agency (AFWA). The performance of the model is given in standard meteorological forecast metrics, and compared to the accuracy of the preceding studies. The accuracy of the model is found to be consistent between the three periods. It is important for model verification that the model and inputs be specified and used in a consistent manner throughout the period of study. For this third phase, the added confidence in model predictions provided by the presence of halo/partial halo observations is demonstrated. Halo/partial halo CMEs, (widths ≥200°) from the retrospective (final) CME list, were found to accompany approximately one half of the events. The shock-predictions of this subset of events have a significantly higher level of confidence and success. Thus, though the observation of a large CME should not be a requirement for a forecast, when one is observed, the confidence in the shock-prediction is greatly increased.

 
 
25   00:00   Possible Physical Mechanism of Antropogenic Contribution to the Weather and the Climate Changes
Voronin, N.; Avakyan, S.
Russian Scientific Center S.I. Vavilow State Optical Institute

Industrial greenhouse effect is usually suggested as a cause of global rise of the surface temperature over the last few decades. In this letter we propose to draw attention the new anthropogenic component Ð influence of powerful radio transmitters (navigation and communication) on the particles in radiation belts of the Earth. This anthropogenic factor affects mainly the electrons from inner and outer belts over the cyclotronic frequencies i.e. frequencies of the Larmor precession. Thus, precipitations simulated by VLF transmitters we suggest to consider as an-thropogenic analogue of the aurora caused by magnetic storm. Thus we can make very important for the modern climatology conclusion that two important features of the modern climatic change: (a) global warming and (b) perma-nent increase in cyclone number (192 cyclones from 1970 to 1992 and 162 over the next 10 years) have the same nature Ð global increase of the number and power of VLF transmitters particularly near maritime coast regions where the cyclogenesis takes place. This conclusion is based on analysis on intensity of the stimulated electronic pre-cipitations which are comparable with the precipitations during the global geomagnetic storms. AreThis splinter meeting is meant to be a discussion forum focused on the significance of indices and proxies presently in use, and on the adoption of new ones in view of a more comprehensive quantitative description of Space Weather phenomena, capable of improving both modeling and prediction operational frameworks.as of the stimulated electronic precipitations and areas of perturbed iono-sphere are linked either with the magnetic force line at which the surface VHL trans-mitter is situated or with the magnetic line at which effect of radio wave on the pitch angle of electron, captured in radiation belt, takes place. In accordance with our calcu-lations rate of the optical excitation of ionosphere in the conjugate point and hence, generation of microwave radiation from Rydberg states reaches 10 % of the effect in the point of the transmitter work. Intensity of precipitations corresponds to the main phase of geomagnetic storm. Thus precipitation of electrons from radiation belts, registered over periods of VFL transmitters have fluxes close to that from the global magnetic storm. Such storm is ac-companied by intensive emission of all the upper atmosphere which is called aurora. Hence, according to results of our investigation these simulated precipitations of elec-trons to ionosphere should cause excitation of Rydberg states with the corresponding emission of microwave radiation with intensity up to 10^Ð12 Ð 10^Ð11 W –mÐ2. High alti-tude experiments showed that microwave emission in 2-10 cm range might influence process of cluster generation in the lower atmosphere. According to our hypothesis that should reflect in changes of the weather and climate parameters. Since radio and VLF transmitters are both products of the industrial activity of 20th century probably it is necessary to take into account their geography and working regime when research solar-weather and solar-climatic phenomena.