Submitted abstracts:
1.
Revisiting sunspot catalogs: data merging and index
construction
F. Clette, L.
Lefévre, T.
Baranyi, A. Ludmány
In this progress report, we summarize the work accomplished for
converting and merging the DPD and the USAF-Mount-Wilson sunspot group
catalogs. This complex operation allowed us to better understand the
specificities of those catalogs and identify systematic choices or
biases attached to each data set. Exploiting the extremely detailed
single-spot information available in the DPD catalog, we can implement
different tunable filters (spatial resolution, classes of features,
group splitting) in order to better match other independent but
less-detailed data sets or also to approximate solar indices. We will
show what we learned when deriving the catalog-based sunspot number and
comparing it to the International Sunspot Index Ri and a few reference
index series. It appears that the inclusion or rejection of tiny
features at the sunspot-pore boundary can play a large role. In our
investigations, we also conclude on an unusual drift of the sunspot
index in the declining phase of the last sunspot cycle (cycle 23),
similar but not identical to some other published studies.
2.
Studies of CME initiation: observations and simulations combined
Lidia van Driel-Gesztelyi,
Tibor Torok
We report on highlights of SOTERIA.solarobs.nce projects led by OBSPARIS, in which we analyse observational signatures of several dynamic events
in the corona and carry out MHD simulations reproducing the main aspects of the observed events. The cases include merging and reconfiguring
filaments (20 Nov. 2003 and 19 May 2007), conversion between twist and writhe helicities in erupting filaments and CMEs (27 May 2002 and
18 February 2003) and the rotation of a sunspot triggering a CME (6 July 2006). The latter study is in collaboration with UNIGRAZ and HVAR.
We also present the new deliverable by OBSPARIS, a web page presenting SOTERIA modelling of observed solar dynamic phenomena,
including some of the above cases as well as a study contributed by KU LEUVEN. This web page will serve as benchmark, tutorial, and information
exchange platform for SOTERIA members. We demonstrate our progress made with this new deliverable, i.e. the completion of the 2010 milestone.
3.
Application of data assimilation to
solar wind forecasting models
Maria Elena Innocenti,
Giovanni
Lapenta, Bojan Vrsnak, Manuela Temmer, Astrid Veronig, Lapo Bettarini,
Edwin Lee, Stefano Markidis, Marina Skender, François Crespon,
Chafih Skandrani
Data Assimilation through Kalman filtering [1,2] is a powerful
statistical tool which
allows to combine modeling and observations to increase the degree of
knowledge of a given system. We
apply this technique to the forecast of solar wind parameters (proton
speed, proton temperature, absolute
value of the magnetic field and proton density) at 1 AU, using the
model described in [3] and ACE data as
observations. The model, which relies on GOES 12 observations of the
percentage of the meridional slice
of the sun covered by coronal holes, grants 1-day and 6-hours in
advance forecasts of the aforementioned
quantities in quiet times (CMEs are not taken into account) during the
declining phase of the solar cycle
and is tailored for specific time intervals. We show that the
application of data assimilation generally
improves the quality of the forecasts during quiet times and, more
notably, extends the periods of applicability of the model, which can
now provide reliable forecasts also in presence of CMEs and for periods
other than the ones it was designed for.
References: [1] R. Kalman, J. Basic Eng. 82, 35 (1960); [2] G. Welch
and G. Bishop, Technical Report TR
95-041, University of North Carolina, Department of Computer Science
(2001); [3] B. Vrsnak, M. Temmer, and A. Veronig, Solar Phys. 240, 315
(2007).
4.
Toward application of the data
assimilation on the space weather models: sensitivity analysis of flip
model
C. Skandrani(1), F.
Crespon(1), G.
Lapenta(2), L. Bettarini(2), M-E. Innocenti(2)
(1)NOVELTIS
(2)KULeuven
It's well known that one of the main source of error in solar wind
models is related to errors in their solar magnetograms inputs.
Data Assimilation technique could be a good candidate to improve inputs
and minimizes errors for solar wind forecasts.
Our purpose here is to start first by studying the sensitivity analysis
of a suitable physics based models of the solar wind expansion:
flip-mhd model (http://code.google.com/p/flip-mhd/) which is used to
determine the ambient solar wind speed and IMF polarity.
Indeed, during the elaboration of the DA, sensitivity analysis, which
studies how perturbations on the model input engender
perturbations on the outputs, can turn out to be a precious tool.
Sensitivity study is performed thanks to a Monte Carlo method (ensemble
method).
We describe and analyze the model error and solar wind parameters
uncertainties for the following objectives:
- to characterize the sensibilities through ensemble variances,
- to estimate the variances and the spatiotemporal structures of the
error in terms of representation of the magnetic and velocity field,
due to the uncertainties of the source surface magnetograms parameters
inputs,
- to study the ensemble spatial error covariances, which consists to
analyze influence functions called "representers" and illustrate the
response
of the model to the input perturbation in a located point of the model.
This allow, without implementing the consuming DA procedure,
to understand better the impact and potential contribution brought by a
single observation data.
First results of the study appear promising in view of implementing
solar wind models by DA technique.
5.
UNIGRAZ progress report
M. Temmer, A. Veronig, W. Hirtenfellner, W. Maierhofer, W. Pötzi, T. Rotter, A. Hanslmeier
We will report about the progress of various deliverables for which
UNIGRAZ is responsible as well as new collaborations within the SOTERIA
consortium. UNIGRAZ has the main deliverable to build a Ca II K
telescope at Kanzelhöhe Observatory within WP3. A second main
deliverable is the implementation of a web-based searchable catalogue
which includes data/events that are produced and maintained by SOTERIA
members. Data from the catalogue will be distributed to the entire
SOTERIA consortium through the SOTERIA VSO, which will be established
by ROB. Besides, fruitful collaborations were raised within the last
year in the frame of.solarobs.ntific studies. Of special interest are here
collaborative studies on coronal holes with LEUVEN and HVAR, flare/CME
event studies and MHD modeling with OBSPARIS and HVAR, flare studies
with LPI, CMEs and ICMEs with UGOE as well as studies on the flare-CME
relationship with
HVAR.
6.
CME and Flare Initiation Challenge
Lapenta, Bettarini, Poedts,
Soenen
collaboration with OBSPARIS
We propose a challenge aimed at testing the difference among different
mathematical models and numerical codes in predicting the initiation
and subsequent initial phases of evolution of CMEs and flares.
This activity stems from the EC-funded collaborative project SOTERIA
(soteria-space.eu) but is open to the world-wide solar community.
We propose different modeling challenges in 2D and in 3D and we present
our first sets of results obtained with different models and codes. The
goal is primarily that of zeroing in on the different outcomes of
different choices of dissipations, compressibility, beyond-MHD models
in determining the role of the different processes of magnetic
reconnection and their impact on the onset and evolution of flares and
CMEs.
We hope the.solarobs.ntific community will be interested and pick up the
challenge. Clearly, modifications to the challenge are still possible
based on the input from the community.
7.
Extrapolation of photospheric vector
magnetograms: Tests and applications
G. Valori, T.
Török, B.
Kliem, V.S. Titov, L. Green, L. van Driel-Gesztelyi, M. Fuhrmann, D.
Baker, A. Wallace, S. Vargas
The validation of models of many important solar phenomena, like
CME initiation and flux emergence, relies on the accurate knowledge of
the magnetic field in the corona. However, the magnetic field is
measurable with sufficient accuracy and resolution only in the lower
strata of the solar atmosphere, mostly at photospheric levels. In this
presentation I will discuss a relaxation technique, known as
magnetofrictional method, that can provide the missing coronal
information via the the numerical solution of the nonlinear force-free
equations in a coronal volume above the photospheric vector
magnetogram. A class of solar-relevant, nonlinear force-free
equilibria, consisting of an arched current channel held in force-free
equilibrium by an external potential field, can be used as a test for
the extrapolation code. I will show that such test-equilibria are
reconstructed by the magnetofrictional code with very high accuracy,
using only the vector field in the bottom boundary as input. In
particular, structural features formed in the interface between the
flux rope and the surrounding arcade---``hyperbolic flux tube' and
``bald patch separatrix surface'---are reliably reproduced, as are the
flux rope twist and the energy and helicity of the configuration.
Finally I will give examples of application to measured vector
magnetograms in both successful and not successful cases, and I will
discuss which are the present limits of extrapolation techniques, and
which criteria can be used to address the degree of reliability of
reconstructed coronal fields.
8.
Progress of SRC-PAS team on analysis
of SphinX and the other solar X-and EUV data
J. Sylwester and S. Gburek
for the
Wroclaw Team
Data obtained from SphinX between February and November 2009 received a
world-wide recognition by the publication of its measurements of X-ray
fluence obtained during the very minimum of solar activity observed in
2009. Such measurements have no precedence. The light curve has been
presented by EOS Bulletin of American Geophysical Union on 23rd
February 2010 (Vol 91, No. 8). The publication has been prepared in
collaboration between the SRC-PAS (J. Sylwester, M. Kowalinski, S.
Gburek and M. Siarkowski) and Lebedev SOTERIA (S. Kuzin) Teams and the
scientists from the Mullard Space Science Laboratory (Prof. K.J.H.
Phillips,University College London, UK), Astronomical Institute of
Czech Academy of Sciences (dr. F. Farnik) and Astronomical Observatory,
National Institute of Astrophysics, Palermo, Italy (Prof. F. Reale).
SphinX observations of particularly well covered AR 11024 has been
undertaken in collaboration of SRC-PAS Team members with the XRT Hinode
Team from Harvard-Smithsonian Center for Astrophysics, Cambridge, USA
and Marshall Space Flight Center NASA (Alexander J. Engell, Marek
Siarkowski, Magda Gryciuk, Janusz Sylwester, Barbara Sylwester, Leon
Golub, Kelly Korreck, Jonathan Cirtain). This study allowed to
investigate more than hundred soft X-ray brightenings seen in the
period 3-13 July 2009 on ~100 thousands of SphinX spectra and ~5
thousands of XRT high-resolution images obtained through thin Be and Ti
filters. Respective common paper is due to be published in November
2010 issue of ApJ.
The collaboration with Prof. Phillips and Prof. V.D. Kuznetsov,
Director of the IZMIRAN institute of Russian Academy of Sciences
(http://www.izmiran.rssi.ru/ ) resulted in publication in 2010 of four
common Papers in ApJ, where interpretation of RESIK Bragg spectrometer
flown aboard the CORONAS-F were published under the SOTERIA umbrella.
RERIK spectra are still very much unreduced. We hope to proceed with
full RESIK data reduction and public access under the SOTERIA follow-up
programme.
Intensive collaboration has been continued on common interpretation of
SphinX and RESIK data. Also results from the previous mission
CORONAS-F, as obtained using SPIRIT and RESIK have been commonly
analyzed by the Lebedev LPI and SRC-PAS Teams. Special attention has
been focused on the flare of 15 April 2002, for which reduction of 800+
spectra have been performed. The write-up of a dedicated paper is
planned for October 20, during the meeting of LPI and SRC-PAS teams in
Wroclaw, Poland.
9.
3-D structure of CMEs and their
interplanetary evolution
V. Bothmer, E. Bosman, M.
Temmer, A.
Veronig, A. Reiners
Since launch in October 2006 more than 500 coronal mass ejections
(CMEs) have been identified in the field of view of the COR 2 imagers
of the SECCHI remote sensing suites on board the two STEREO spacecraft.
The viewing perspectives of these events changed with angular
separation of the two STEREO spacecraft. For a subset of about 80
"best of" events, selected based on the white-light brightness
appearances of the CMEs in the COR2s field of view, the GCS-modell has
been applied to model their 3-D structure. The modeling results have
been compared with the identified low coronal and photospheric source
region properties as inferred from SOHO/MDI/EIT, SDO/AIA and Proba2
observations. Here we present a summary of the results of the ongoing
analysis and the implications for the 3-D structure of CMEs and
their interplanetary evolution.
10.
Status of SphinX data Catalogues
available for SOTERIA Consortium
S. Gburek and J. Sylwester
for the
Wroclaw Team
Solar Photometer in X-rays (SphinX) was an instrument designed to
observe the Sun in X-rays in the energy range 0.85 -15.00 keV.
SphinX was incorporated within the Russian TESIS X and EUV telescope
complex aboard the CORONAS-Photon satellite which was launched on
January 30,
2009 at 13:30 UT from the Plesetsk Cosmodrome, northern Russia. Since
February, 2009 SphinX has been measuring solar X-ray radiation nearly
continuously till the end of spacecraft active operation in space on 29
November 2009. All SphinX data collected during the mission are kept on
three mirror
servers at different geographical locations in EU. At present SphinX
data undergo reduction to level-1 format. About 40% of the entire
SphinX data files have
been already reduced. We explain the Sphinx archive structure, discuss
access to data repositories and describe data dissemination methods and
their reduction
procedure. We show how particular SphinX data products contribute to
SOTERIA.
11.
Heliospheric Propagation of Coronal
Disturbances and their Space Weather Consequences (Collaborative
research on WP4 Task 4.1 & Deliverable 4.2)
Bojan Vršnak1,
Susanne
Vennerstrom2, Thea Falkenberg2, Maria Elena Innocenti3,
Astrid Veronig4, Manuela Temmer4, Thomas Rotter4, Lidia van Driel-Gesztelyi5,
Francois Crespon6, Mateja Dumbović1, Tomislav Žic1, Giuliana Verbanac7, Christian
Most1,8, Tanja Rollet4,8
1Hvar Observatory, Faculty of Geodesy, Zagreb, Croatia (HVAR)
2National Space Institute, Technical University of Denmark,
Kobenhavn, Denmark (DTU)
3 Afdeling Plasma-astrofysica, Katholieke Universiteit
Leuven, Heverlee, Belgium (KULeuven)
4 Institute of Physics, University of Graz, Graz, Austria
(UNIGRAZ)
5 Observatoire de Paris, Meudon, France (OBSPARIS)
6 Noveltis, Ramonville-Saint-Agne, France (NOVELTIS)
7Department of Geophysics, Faculty of Science, Zagreb,
Croatia (non-SOTERIA)
8Space Research Institute, Austrian Academy of Sciences,
Graz, Austria (non-SOTERIA)
We summarize the results achieved in past two years through the
collaborative research in the frame of Task 4.1 of WP4, which will be
presented in Deliverable 4.2. The research was focused on the
propagation of interplanetary coronal mass ejections (ICMEs) and solar
wind high-speed streams (HSSs) as well as on the two related aspects of
space weather: the geomagnetic activity and variations of the
cosmic ray flux. Various forecasting aspects related to these phenomena
are also considered. Regarding the ICME propagation, we present a
comparison of performances of the analytical “drag based model” and the
numerical MHD model ENLIL, and compare both with measurements of ICME
kinematics based on STEREO and interplanetary.solarobs.tillation
observations. Regarding HSSs, we present the advanced version of the
empirical model which relates the coronal hole size/position with the
characteristics of solar wind at 1 AU and the related geomagnetic
activity. The model is significantly improved, especially for specific
solar wind parameters like the solar wind velocity, by applying the
data assimilation technique, which provides a 6-hour resolution
forecast of improved accuracy. Finally, we present some new results
concerning modulations of the cosmic ray flux caused by ICMEs and HSSs.
12.
New SSI and TSI reconstruction
suggests large value of the radiative solar forcing
A. I. Shapiro (1), W.
Schmutz
(1), G. Thuillier (2) , E. Rozanov (1,3), M. Haberreiter
(1), M. Schoell (1, 4), A. V. Shapiro (1,3), S. Nyeki
(1)
(1) Physikalisch-Meteorologishes Observatorium Davos, World Radiation
Center, Dorfstrasse 33, 7260 Davos Dorf, Switzerland
(2) LATMOS-CNRS Bp 3, 91371 Verrieres le Buisson, France
(3) Institute for Atmospheric and Climate.solarobs.nce ETH, Zurich,
Switzerland
(4) Institute for Astronomy ETH, Zurich, Switzerland
We have developed and published the COde for Solar Irradiance (COSI)
which allows us to calculate the entire solar spectrum. COSI reproduces
the spectral irradiance measured by SOLSTICE (up to 320 nm) and SIM
(from 320 nm onward) onboard the SORCE satellite during the 2008 solar
minimum as well as SOLSPEC during the ATLAS 3 mission in 1994 with high
accuracy.
COSI is also used as a tool for modeling the variability of the solar
irradiance. In our new reconstruction we represent the quiet Sun as a
combination of two components. The first corresponds to the least
active areas of the Sun as presently observed, while the second
component is responsible for the magnetic activity of the quiet Sun.
The time-dependent filling factors of these components are calculated
based on the solar activity as derived from cosmogenic isotope
concentrations in natural archieves. This allows us to obtain a
time-dependent reconstructed solar spectrum from 7000 BC to the present
with a temporal resolution of 22 years. From 1610 onward we have
additional information from sunspot numbers, which allows the
reconstruction of the spectral solar irradiance with a yearly
resolution.
These basic assumptions lead to a total and spectral solar irradiance
that was substantially lower during the Maunder minimum than observed
today. The difference is remarkably larger than other estimations
published in the recent literature. Using our reconstruction as an
input to a chemistry-climate model we show that the enhanced UV
variability results in significant variations of stratospheric ozone
and temperature.
13.
New methods to monitor the auroral
oval location and activity based on magnetic and GPS data
S. Vennerstrom(1), F.
Crespon(2), T.
Asikainen(3), K. Mursula (3), F. Christiansen(1)
(1)National Space Institute, Technical University of Denmark,
Copenhagen, Denmark (DTU),
(2) Noveltis, Ramonville-Saint-Agne, France (NOVELTIS),
(3)Department of physical.solarobs.nces, University of Oulu, Oulu, Finland
(UOulu)
Monitoring the location of the auroral region is important in a wide
range a space weather applications ranging from communication through
effects of high-energy radiation to ground induced currents (GIC’s). In
consequence the latitudinal shifts of this region are constantly being
monitored by the US DMSP satellite program, by measuring particle
precipitation.
We present here two new methods to derive the auroral oval location.
One method based on magnetic field observations from low Earth
orbit satellites developed at DTU and the other based on high latitude
TEC maps derived from GPS data by NOVELTIS. We consider these methods
as complimentary to the estimates based on particle precipitation
measurements. We compare these two new methods and we also compare the
results to the auroral boundaries inferred from precipitation
data. Various precipitation boundaries are considered, both as inferred
from POES data and derived by UOulu and as inferred from the DMSP data.
We find a good correspondence between the metods. In addition it is
demonstrated that the magnetic data can be used to monitor the
intensity of the auroral electrojets. For the northern hemisphere the
variation in intensity is well correlated with the AU and AL indices.
14.
Overview of WP4 activities and
collaborations
S. Vennerstrom and all WP4
participants and collaborators: Hvar, UOulu, LPI, NOVELTIS, IEEA,
KULeuven, MTA-KFKI-RMKI, ROB, UNIGRAZ, DTU, CCMC
Focus of the second year of the work in WP4 has been on a set of
collaborative.solarobs.ntific projects ranging from heliospheric propagation
of solar events to the effects on the Earth environment and on
scientific instruments operating in space as well as
communication. Three.solarobs.ntific reports are being completed as
deliverables D4.2, D4.3 and D4.5. Here we provide a short overview of
the work and the
collaborations.
15.
Geomagnetic shielding of SEPs – local
time variation in cut-off latitude
S. Vennerstrom(1), T.
Asikainen(2),
K.Mursula(2),
(1)National Space Institute, Technical University of Denmark,
Copenhagen, Denmark (DTU),
(2)Department of physical.solarobs.nces, University of Oulu, Oulu, Finland
(UOulu)
An important property of the Earth’s magnetic field in the context of
space weather, is its ability to shield spacecraft located well within
the magnetosphere from solar energetic particles (SEP’s). For polar
orbiting spacecraft in low-Earth orbit a particular important aspect is
the so-called cut-off latitude. The cut-off latitude is observed as a
characteristic steep drop in particle flux seen in a narrow latitude
band, when a polar orbiting LEO space craft crosses from high to low
latitudes during solar energetic particle (SEP) events. The cut-off
latitude is known to vary with the geomagnetic Dst index, but
significant deviations are observed that appear to be very local time
dependent.
In SOTERIA two important goals are directly connected to Dst and local
time variations of magnetic activity: (a) to create new measures of
geomagnetic activity based on magnetic observations from polar orbiting
satellites, and (b) to make a new ground-based Dst like index, Dcx,
based on a more dense ring of low latitude ground magnetic
observatories than utilized for Dst. Both of these types of
measurements, satellites and ground-based networks, can naturally be
used to monitor local time variations of low-latitude magnetic
disturbances. We have therefore made a study of the association between
cut off latitude variations for different local times and the variation
of the local magnetic field magnitude at these local times. The local
time variations of cut-off latitude is determined by using simultaneous
observations of energetic protons from the POES satellites and also
from SAMPEX. We examine two events in detail and find a good
association between magnetic disturbances and cut off latitude
variations, but further work seems to be needed to separate ionospheric
and magnetospheric contributions to low and mid-latitude magnetic
disturbances.
16.
Calibrated fluxes of energetic
particles and their usage in magnetospheric diagnostics
Timo
Asikainen(1), Kalevi
Mursula(1), Susanne Vennerstom(2)
(1)Department of Physics Centre of
Excellence in Research, University of Oulu, Finland (UOulu)
(2)National Space Institute, Technical University of Denmark,
Copenhagen, Denmark (DTU)
Low-altitude polar orbiting NOAA/POES satellites have measured fluxes
of energetic particles nearly continuously from 1978 up to the present,
covering almost three solar cycles. However, using these data for
long-term studies includes several problems, most importantly due the
significant degradation of the solid state detectors of the energetic
particle (MEPED) instruments caused by radiation. This tends to
increase the effective energy thresholds of the instrument, leading to
underestimated particle fluxes already a couple of years after
satellite launch. We have recently analyzed the radiation damage
suffered by the MEPED instruments and calibrated the entire dataset for
these effects, thus producing a reliable long-term data base of
magnetospheric energetic particles.
Here we discuss the calibration procedure and present the corrected
fluxes. We note that the corrected fluxes of energetic particles offer
interesting opportunities to study the Earth's space environment. E.g.,
they can be used to estimate more reliably the structure and dynamics
of the magnetospheric tail by measuring the so called isotropic
boundary of energetic particles. The location of this boundary is known
to be a good proxy of the tail electric current, reflecting the
elongation of the tail during magnetospheric substorms and storms. We
have used the isotropic boundary to study the dynamics of the auroral
oval, as well as modeling the contribution of the tail current and
other current systems to the corrected Dst index. We also compare the
fluxes to the ground-based Dcx index (provided by UOulu) and the
satellite based Dst index (provided by DTU) and discuss their relation.
17.
Simulation of Energetic Storm Particle events with Solpenco
K.
Kecskemety
Energetic storm particle (ESP) events appear around the shock passage
during solar energetic particle events associated with coronal mass
ejections. In the framework of SOTERIA D4.2 RMKI is involved in Space
weather model validation and forecasting using the Solar Particle
Engineering Code. On a sample of more than 20 events the characteristic
features are reproduced and their variation is analyzed as a function
of various parameters (shock speed, longitude, particle energy).
18.
Model and visualization software for the nowcasting of the middle
atmosphere
T. Egorova, E. Rozanov, N.
Hochmuth, A.V, Shapiro, A.I. Shapiro and W. Schmutz
We have developed climate-chemistry-ionosphere model SOCOL which is
based on a general circulation model and includes complete
representation of the chemistry of neutral and ionized species in the
atmosphere from the ground up to the mesopause. To validate the model
we have simulated the response of the neutral and charged species in
the middle atmosphere to the short-term increase of the solar UV
irradiance in January 2004 and severe solar proton events in
October-November 2003 and January 2005. The model functioning in the
nowcasting mode will be illustrated using specially designed
visualization software.
19.
A prediction for the 24th solar cycle obtained combining various methods
R. Brajša (1), A.
Hanslmeier (2), A. Ludmany (3), J. Muraközy (3), G. Verbanac
(4), H. Wöhl (5),
M. Roth (5), and L. Svalgaard (6)
(1)Hvar Observatory, Faculty of Geodesy, University of Zagreb, Croatia
(2)Institut für Physik, IGAM, Universität Graz, Austria
(3)Heliopysical Observatory, HAS, Debrecen, Hungary
(4)Geophysical Institute, Faculty of Science, University of Zagreb,
Croatia
(5)Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany
(6)HEPL, Stanford University, CA, USA
We predict the time and the amplitude of the next, 24th solar cycle
using the data available in September 2010. The emphasis in this
analysis is on the minimum - maximum method with the time lag. The
correlation coefficient of the activity levels, represented by the
relative sunspot number, sharply raises for positive time lags after
the preceding minimum. The monthly and yearly values of the relative
sunspot number are used to obtain the mathematical representation of
the linear relationship of the values in and around activity minima and
following maxima. This enables an improved prediction of the next solar
activity maximum's amplitude. Further, the result obtained in this way
are combined with the results obtained by different methods, such as
the asymmetry method and the ARMA method and with the published
predictions. Finally, correlations between the starting latitude and
the cycle maximum, as well as between the number of spotless days in
the minimum and the cycle maximum are investigated. The final result of
a combination of the methods mentioned above predicts a lower amplitude
of the next 24th solar activity maximum in comparison with several
previous cycles.
20.
Ionospheric Scintillations: Their relationship to magnetic storms and
the effect on technological systems
Y. Béniguel (1), F.
Crespon (2), C. Skandrani (2), S. Vennerstrom (3)
(1) IEEA, Courbevoie, France
(2) Noveltis, Toulouse, France
(3) DTU, Copenhagen, Denmark
As a result of propagation through ionosphere electron density
irregularities, transionospheric radio signals may experience amplitude
and phase fluctuations. The.solarobs.tillation activity behaves differently
with latitude. It is more intense at low latitudes (-20° to 20°
magnetic latitude) and during periods of high solar activity. In this
region, the signal fluctuations specially occur during equinoxes, after
sunset, and last a few hours. Scintillation also occurs at high
latitudes (> 60°) but with different characteristics and a
reduced intensity. The magnetic field plays an important role which
results in elongated bubbles in that direction and consequently in an
anisotropic medium. At mid latitudes,.solarobs.tillation was only observed
in the occurrence of magnetic storms. The medium’s drift velocity and
its direction are also important parameters to be considered. These
fluctuations result in signal degradation from VHF up to C band. The
corresponding errors are the most prominent errors for Global
Navigation Satellite Systems (GNSS).
This paper will review the.solarobs.tillation characteristics, its
relationship to the magnetic activity and the effect on communication
and navigation systems. One model to estimate these.solarobs.tillation and
their effects will be presented.
21.
Debrecen sunspot catalogue compilation, the side story
Lajos Gyori
A sunspot catalogue, as it can be
guessed by its name, contains data of the sunspots (position, area,
magnetic field, structure). Therefore, the main task of the catalogue
compilation is to find the sunspots in solar images and determine the
data characterizing them, possibly in an automatic way. To make a
catalogue complete we must gather the solar images from a wide
variety of observatories. These images are taken in different ways and
their qualities are also different. Furthermore, the relevant
informations needed when processing them are linked to them
differently. Generally, while a solar image (especially a
photoheliogram) and its relevant data appears in the computer, it
goes through a number of hands, which means several occasions to make
errors. That, even in these circumstances, the catalogue should be
compiled in an automated way as much as possible and should be highly
reliable, several problems must be solved and the different steps of
the processing must be continuously checked. Here we give a fortaste of
these problems.
22.
Modeling field-aligned currents from single orbit magnetic data.
Freddy Christiansen
and Susanne Vennerstrøm (DTU Space), and
Francois Crespon (Noveltis)
We estimate field-aligned and ionospheric
currents for a number of storm time events from magnetic data from
single orbits of the two Low Earth Orbiting satellites, Oersted and
Champ.
The field-aligned currents are
parameterized as simple current segments of Region 0, Region 1, and
Region 2 currents. Region 1 and 2 currents are described by 4 current
segments each, dayside/nightside and dawn/dusk, while the Region 0
current is described by a single segment. Assuming ionospheric
conductivities, the currents are closed in the ionosphere and the full
magnetic perturbation from the field-aligned/ionospheric currents are
fitted to the magnetic observations from the Oersted and Champ
satellites.
Using maps of total electron content
computed from GPS data to estimate the ionospheric conductivities we
arrive at a snapshot of the near-earth current systems during magnetic
storms that may be compared to conventional statistical appraches.
From the ionospheric currents and
conductivities we compute the Joule heating of the ionosphere during
storm time events.
23.
Long-term reconstructions of the Total
Solar Irradiance (TSI)
L.E.A. Vieira, T. Dudok de
Wit, M. Kretzschmar, G. Cessateur
The solar electromagnetic emission (the solar irradiance) is the main
source of energy of the highly coupled geophysical system.
Space-based
observations of the solar irradiance proved that it is extremely
variable. Furthermore, observations of several components of the solar
atmosphere
have shown that the variability of the solar irradiance is closely
related to the evolution of the structure of the solar magnetic field.
Although
these observations have imposed constraints on the amplitude of the
variability through the solar magnetic activity cycle, it was not
possible
to assess long-term trends. Changes of the irradiance level on
time-scales from decades to millennia affect directly the Earth’s
climate, although
the level of these effects is still uncertain. In order to estimate the
long-term evolution of the total (and spectral) solar irradiance,
several
models have been developed. These models are based on the proxies of
the evolution of the solar magnetic flux, such as the sunspot number
and cosmogenic
isotopes recorded on natural archives. Here we revise the most recent
reconstructions of the solar irradiance that can be employed as
realistic descriptions of the
external source of heat of the geophysical system for paleo-climate
models.
24.
How is the solar spectral variability
in the EUV related to features on the Sun ?
T. Dudok de Wit (LPC2E,
Orléans), F. Goryaev (Lebedev Physical Inst., Moscow),
M. Kretzschmar (LPC2E, Orléans), J. Lilensten (LPG, Grenoble),
J. Aboudarham (LESIA, Paris)
One of the main challenges with solar spectral irradiance is to
understand what causes its variability. The contributions from features
such as plages and faculae are well understood. The recent and
exceptionally long solar minimum, however, has shown that the classical
picture needs to be refined. In particular, it suggests that coronal
holes may also play a significant role. This contribution is crucial
for
assessing the long-term variability of the Sun.
We address this problem from a statistical point of view and apply a
Bayesian blind source separation approach to 8 years of spectral
irradiance data from TIMED/SEE to investigate the causes of the
variability. Since the method is empirical, there is no model bias. We
find that the variability in the EUV can be expressed in terms of three
elementary spectra with differing time evolutions. A DEM analysis
reveals that one of the spectra indeed decribes the cool contribution
from coronal holes while the two other ones decribe the quiet Sun and
active regions. It is remarkable that a statistical technique provides
such new insight into the solar EUV irradiance. These results also
provide guidance for the definition of new solar proxies.
25.
What hemispheric and longitudinal
asymmetries imply about the Sun and why are they important for the
Earth’s space environment?
Kalevi Mursula(1), Ilpo
Virtanen(1), Liyun Zhang(1,2), Ilya Usoskin(3), Timo Asikainen(1)
Andras Ludmany(4), Judit Murakozy(4)
(1)Department of Physics, University of Oulu, Finland (UOulu)
(2)Key Laboratory of Solar Activity, NAO, CAS, Beijing, China
(3)Sodankylä Geophysical Observatory, University of Oulu, Finland
(4) Konkoly Observatory, Hungary (KO)
It is known since long that solar activity is unevenly distributed over
the solar surface, both along the solar longitude and between the two
solar hemispheres. Related studies of hemispheric and longitudinal
asymmetries have been pursued for long, using different methods and
different activity parameters. Unfortunately, these studies have so far
remained at a rather marginal status due to the rather inconclusive and
sporadic occurrence of the asymmetries.
However, it is known since recently that the solar hemispheric
asymmetries depict systematic long-term patterns that have prevailed
for more than a century. Also, using a dynamic reference frame, more
significant longitudinal asymmetries have been found that are quite
similar for different solar parameters. Also, solar longitudinal
asymmetries depict systematic long-term patterns that seem to be common
for all cool stars.
We review here these recent developments on solar hemispheric and
longitudinal asymmetries and their role in improving our understanding
solar activity and solar magnetic field generation. We also note that
solar asymmetries affect the Earth’s space environment and that the
newly found patterns allow the possibility to make better long-term
forecasts of solar related disturbances in near-Earth space.
26.
Radiation belts effects on the
functioning of the TESIS and SPHINX instruments on-board CORONAS-Photon
and comparison of the measured data with the SPENVIS model predictions
S. Kuzin, V. Slemzin, A. Ulyanov, S. Bogachev, - LPI (Moscow,
Russia) J. Sylwester, S. Gburek, P. Podgorski, M. Kowalinski - SRC PAN
(Wroclaw, Poland)
Space instruments on LEO satellites work
under the impact of various environmental factors, which should be
taken into account to prevent
distortion of the observational data and gradual degradation of the
payload. For solar imaging telescopes and photometers the most
important factor is the radiation of energetic particles which produce
a spontaneous background in the detectors.
The influence of such radiation on instrument operation can be
estimated with the use of the space environment models. These models
are embedded in dedicated software and available via standalone or the
Internet interfaces like, for instance, SPENVIS interface. Obtained
from models estimations of the particle impact on the instrumentation
are useful for designing necessary shielding at the instrument
development phase.
The report describes radiation effects observed in the TESIS and SphinX
instrument data. Issues related to construction of both
instruments are addressed as well. The instruments operated for nine
months (February – November, 2009) on-board CORONAS-Photon satellite
(LEO spacecraft). In addition to solar X-ray flux the instruments
registered time-and space-dependent signal produced mainly by charged
particles.
An analysis of this particle signal is performed. The analysis
results are compared to the results obtained from simulations in
SPENVIS. In particular, it was found that the spatial distribution of
the TESIS particle-produced signal covers the region of the South
Atlantic
Anomaly (SAA), so TESIS was mostly sensitive to protons. The spatial
distribution of the SphinX particle signal had enhancements in SAA and
in the polar ovals, what corresponds to SphinX detector sensitivity to
protons as well as to electrons. The mean total dose of the energetic
particles accumulated by the TESIS detectors during one day of flight
per one pixel was found to be well agreed with the SPENVIS dose
estimations.
27.
Status of SWAP and LYRA data
David Berghmans
PROBA2 was launched successfully in
November last year. The commissioning phase of spacecraft and
instrument ended in March 2010. Here we present the current status of
the two solar instruments onboard, SWAP and LYRA. SWAP is an EUV imager
of the solar corona and LYRA is a UV radiometer. Special attention will
be given to the currently available data products.