Plenary - Space Weather Forecast Verification
Peter Wintoft, Ioanna Tsagouri, Alan Thomson, Andrew Bushell
Friday 22/11, 09:00 - 10:30 and 11:00 - 12:30
Forecast verification within the meteorological community has a long tradition, starting in the 1880's and with the
introduction of a new verification framework in the mid-1980's. Forecast verification is the process of assessing the
quality of a forecast, both in absolute terms and for comparing forecast models. Evaluating the quality of space weather
forecasting models faces similar challenges as for terrestrial weather forecasting. In this session we invite presentations
related to space weather nowcast and forecast verification. We welcome contributions from forecasters concerned with,
for example,
- forecast verification applied by forecast providers;
- future development of forecast verification; * communicating verification results and requirements between users and providers
- metaverification -- evaluating performance measures;
- magnetic and other space weather indices;
- ground effects of space weather;
- ionospheric and magnetospheric processes;
- solar and interplanetary data.
Oral contributions
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09:00
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A Critical View on the Space Weather Forecasts at the Regional Warning Center in Belgium
Devos, Andy; Verbeeck, Cis; Robbrecht, Eva
Royal Observatory of Belgium, BELGIUM
The ISES Regional Warning Center in Brussels for space weather
forecasting at the Royal Observatory of Belgium (ROB) has been
providing daily space weather forecasts for more than a decade. As part
of the FP7 project AFFECTS (Advanced Forecast For Ensuring
Communications Through Space), ROB has applied a thorough verification
analysis of the forecasts of the RWC over the past decade. From now on
this procedure will be applied annually.
Forecasts of fundamental space weather parameters as
the K value (the local geomagnetic index), the 10.7 cm radio flux and
solar flaring probabilities are under critical evaluation. Strengths
and weaknesses are determined compared to common numeric models. The
verification analysis can easily be extended with extra analysis and
facilitate embedding new forecasting models in the future.
Descriptive model statistics, common verification
measures, error analysis and conditional plots between forecasts and
observations are available on http://www.sidc.be/forecastverification.
The analysis allows us for example to detect the influence of solar
activity on the confidence level of the forecasts. The output aids to
identify the strong and weak points of forecasting as well as those of
the models considered. As such, it creates the opportunity to
continuously reevaluate, stimulate ideas for improvement and increase
the reliability of space weather forecasting.
This work has received funding from the European Commission FP7 Project AFFECTS (263506).
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2 |
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09:30
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Developing an Ensemble Prediction System for Operational Space Weather Forecasting
de Koning, Curt A1; Pizzo, Vic2; Odstrcil, Dusan3
1University of Colorado, UNITED STATES;
2NOAA/SWPC, UNITED STATES;
3George Mason University, UNITED STATES
At present, almost all space weather forecasts are made using
a deterministic approach to numerical space weather prediction (NSWP),
that is, a single forecast (estimate of the future state of the
heliosphere) is obtained from a single known initial state. However,
due to intrinsic uncertainties in initial conditions, finite
model resolution, and the use of simplifying MHD equations that do not
fully capture the relevant processes in the heliosphere, forecast
uncertainty and predictability limitations are an important, but
unexplored, property of NSWP. Dynamically specifying an error for each
forecast is essential for assessing the quality of a forecast, both in
absolute terms and for comparing forecast models.
We describe ongoing research on an ensemble prediction
system for use in an operational space weather environment. The
numerical model used in our ensemble prediction system is Enlil, a
time-dependent, 3D-MHD code that predicts CME arrival time at Earth. We
assess the relative importance of the model inputs (CME size, speed,
and direction as derived from near-real-time coronagraph observations),
as well as background stream structures, for determining an accurate
arrival time at Earth and the contribution of these inputs to the
forecast uncertainty. We also discuss ways of analyzing the output from
a multitude of model runs to arrive at a consensus forecast. Finally,
we present an ensemble visualization that will convey information about
the ensemble inputs and forecast.
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3 |
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10:00
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The NWRA Flare-Forecast Comparison Workshops: Approaches for Meaningful Verification and Comparison.
Barnes, Graham1; Leka, K.D.1; The Int'l Flare Forecasting, Comparison Group2
1NWRA, UNITED STATES;
2N/A, UNITED STATES
Two workshops have been held recently, in 2009 and 2013, to
begin systematic comparisons of methods for forecasting solar flares.
We discuss here the requirements for the data and the methods in order
to provide meaningful comparisons of the performance of participating
methods. These include standardized data sets for input to the
forecasting methods, and standardized event definitions that allow for
statistically useful sample sizes. Crucially, meaningful comparisons
require the use of standard verification statistics such as skill
scores and reliability estimates. Given the often low sample size for
the larger solar events, estimates of the uncertainties in these
verification statistics are particularly important. We present here the
approaches used for these two workshops, and some of the preliminary
results which have been obtained thus far, with a particular emphasis
on the uncertainty estimates.
Funding for the workshops and the data analysis was
provided by NASA/Living with a Star contract NNH09CE72C and NASA/Guest
Investigator contract NNH12CG10C.
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4 |
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10:15
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Statistical Study of False Alarms of Geomagnetic Storms
Leer, Kristoffer1; Vennerstrom, Susanne1; Veronig, A.2; Rodriguez, L.3; Vrsnak, B.4; Dumbovic, M.4
1DTU Space, DENMARK;
2UniGraz, AUSTRIA;
3ROB, BELGIUM;
4HVAR Observatory, CROATIA
Coronal Mass Ejections (CMEs) are known to cause geomagnetic
storms on Earth. However, not all CMEs will trigger geomagnetic storms,
even if they are heading towards the Earth. In this study, front side
halo CMEs with speed larger than 500 km/s have been identified from the
SOHO LASCO catalogue. A subset of these halo CMEs did not cause a
geomagnetic storm the following four days and have therefore been
considered as false alarms. The properties of these events are
investigated and discussed here. Their statistics are compared to the
geo-effective CMEs.
The ability to identify potential false alarms is
considered as an important factor when forecasting geomagnetic storms.
It would therefore be very helpful if there were a signature in the
solar data that could indicate that a CME is a false alarm. The
strength and position of associated flares have been considered as
possible candidates for false alarm signature.
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11:00
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Forecast Evaluation as Applied to Geomagnetic Activity Categories
Clarke, Ellen1; Thomson, Alan2
1British Geological Survey, UNITED KINGDOM;
2British Geological survey, UNITED KINGDOM
Daily forecasts of geomagnetic activity have been provided by
BGS since the 1990s. The predictions are globally averaged levels of
activity over a 24-hour period, going from noon to noon (UT), for one,
two and three periods ahead. Noon to noon was chosen in order to
capture storms occurring in the night time local to the UK. Four
possible categories are used: QUIET-UNSETTLED (Ap <= 15); ACTIVE (16 <= Ap <= 29); MINOR-STORM (30 <= Ap <= 49); and MAJOR-STORM (Ap
>= 50). These forecasts are prepared daily by a duty forecaster
reviewing all available information on solar activity, solar wind
parameters and other space weather data, to predict the impact at the
Earth. Recipients of these forecasts have been power companies and the
oil and gas industry.
Evaluation methods for categorical forecasts of this
type are not yet well established in Space Weather, unlike those used
for meteorological forecasts. Using examples applied in meteorology, we
first investigate the use of various skill scores and other metrics for
a "STORM" vs. "NO-STORM" prediction using 2x2 contingency tables. We
then extend this to 4x4 contingency tables for predictions which fall
into all 4 categories.
Results over 14 years are presented and we discuss the
merits of equitable skill scores (ESS), such as that proposed by Gandin
and Murphy (1992) and improved by Gerritt (1992) for forecasts of more
than two categories. Comparisons are made between individual
forecasters, over time and also against benchmark forecasts. The value
of ESS is discussed with respect to both the end-user and the
individual forecasters.
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11:30
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Verification and Validation System of the UAH-SWS Service
Guerrero, Antonio1; Cid, Consuelo1; Cerrato, Yolanda1; Saiz, Elena1; Aguado, Jesús2; Palacios, Judith1
1University of Alcala, Space Research Group - Space Weather, SPAIN;
2E.U. Cardenal Cisneros, Space Research Group - Space Weather, SPAIN
The adopted model for verification and validation of the
UAH-SWS (Space Weather Service of the University of Alcala) has been
running in V&V (Verification and Validation) mode during more than
one year. Data of every step involved in the process to produce the
outputs of the service have been saved in order to be able to reproduce
the execution of different versions of the software when needed. We
show in this presentation, the structure of the system and the
configuration of the modules we have adopted in order to accomplish the
needs for V&V. We review some hints and failures of the service
allowing us to assess the accuracy of the physics of the model by being
able to discard failures due to software design or operation errors.
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11:45
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Exploring the use of ESPAS Data for Validation of a Thermosphere-Ionosphere Physical Model Data Assimilation System
Bushell, Andrew; Henley, Edmund; Jackson, David
Met Office, UNITED KINGDOM
As test users for FP7 project ESPAS, we plan to exploit the Near-Earth Space Data Infrastructure for e-Science
which is currently under development for a set of experimental cases
(historical events, not in real time) in which a
thermosphere-ionosphere physical model data assimilation system will
run for an extended period.
A free-running simulation of a selected case run with the Coupled Middle Atmosphere Thermosphere
(CMAT2) model, developed at University College London, is under way to
produce results for comparison with data accessible from the ESPAS
system. The purpose of this activity is (i) to gain experience with
accessing data from the system and (ii) to establish what ESPAS data is
best-suited for comparison with the model output either for validation
or for data assimilation purposes. Preliminary assessment may be at the
level of spatial- and time-aggregated fields from the model and data,
although for data assimilation purposes the requirement is rather for
comparison to be carried out locally, which implies access to
individual profiles (satellite passes) from the database.
In order to run an experiment with the CMAT2 model as
part of a data assimilation system that cycles through an extended case
period, there is a further requirement to access metadata with which to
calculate errors associated with observation data, used
in quality control of data assimilation and
to calculate the weighting given to the data (observation
error covariance matrix) when calculating the optimal model analysis.
Such scenarios explore both the behaviour of the
model data assimilation system and that of the ESPAS data
infrastructure, helping to define its relevance for future user
communities.
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12:00
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Verification of DIAS Ionospheric Forecasts in the high Latitude Ionosphere
Tsagouri, Ioanna; Belehaki, Anna
National Observatory of Athens, GREECE
Ionospheric forecasting products and services for Europe are
provided routinely by the European Digital upper Atmosphere Server
(DIAS, http://dias.space.noa.gr). These include alerts and warnings for
upcoming ionospheric storm time disturbances as well as single station
and regional ionospheric forecasts up to 24 hours ahead for the middle
latitude European region. As a step forward, in the frame of the
ESA/SSA Programme the DIAS forecasting services are upgraded to cover
the whole European region, including Scandinavia, based on the expanded
implementation of the Solar Wind driven autoregression model for
Ionospheric short-term Forecast (SWIF).
In the operational mode, SWIF combines historical and
real-time ionospheric observations with solar wind parameters obtained
in real time at L1 point from ACE spacecraft through the cooperation of
an autoregression forecasting algorithm, namely TSAR with an empirical
ionospheric storm time model, namely STIM that is triggered by solar
wind disturbances detected by STIM's alert detection algorithm. The
ionospheric storm time response is then empirically formulated taken
into account the latitude and the local time of the observation point
at the storm onset.
While SWIF's prediction efficiency has been fully
documented previously for the middle latitude ionosphere, the work
presented here includes the evaluation of the SWIF's performance over
high latitude locations under disturbed geophysical conditions. For
this purpose, high latitude foF2 observations obtained during a
significant number of storm events occurred in the previous as well as
the current solar cycle are analyzed in respect with the foF2 reference
level and the model's predictions. The results verify the validity of
SWIF's storm alert detection algorithm for high latitudes and quantify
the accuracy of SWIF's forecasts through relevant metrics' estimations.
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12:15
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Verifying GIC Nowcast Models with Geo-Electric Field Measurements
Kelly, Gemma S.; Beggan, Ciaran D.; Shanahan, Tom; Thomson, Alan W.P.
British Geological Survey, UNITED KINGDOM
To understand how space weather impacts the GB power grid, the
British Geological Survey Geomagnetism team have developed a near
real-time system for "nowcasting" geomagnetically induced currents in
the high voltage electrical network. External magnetic field
measurements from the three UK geomagnetic observatories (Lerwick,
Eskdalemuir and Hartland) are used to predict the induced surface
electric field within the conductive Earth. A model of the network
topology of the power grid is then used to determine the size of GICs
at each node from the predicted electric field.
Previously we have been unable to verify the electric
field model, as electric field measurements have not been routinely
undertaken anywhere in the UK. However, in 2012, the British Geological
Survey initiated a project to produce long-term measurements of the
electric field at each of our observatories. We are now able to make
comparisons between the output from our electric field model and
measured electric field data.
We describe the field set up and instrumentation and
present our initial results from this project, including comparisons
between measured and modelled data for recent geomagnetic storms.
The measurements are already helping us to constrain
our electric field models and hence should improve the estimation of
induced currents in the GB power system. The results will also
ultimately aid numerical model developments of surface conductivity.
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Connecting white Light to In Situ Observations of Coronal Mass Ejections from the Sun to 1 AU
Möstl, C.1; Amla, K.2; Hall, J. R.2; Liewer, P. C.2; De Jong, E.2; Veronig, A.1; Rollett, T.1; Temmer, M.1; Liu, Y.3; Davies, J. A.4; Lugaz, N.5; Farrugia, C. J.5; Luhmann, J. G.6; Galvin, A. B.5
1Kanzelhöhe Observatory-IGAM, Institute of Physics, University of Graz, AUSTRIA;
2Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, UNITED STATES;
3State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, CHINA;
4RAL Space, Harwell Oxford, Didcot, UNITED KINGDOM;
5Space Science Center and Department of Physics, University of New Hampshire, Durham, NH, UNITED STATES;
6Space Science Laboratory, University of California, Berkeley, CA, UNITED STATES
We study the feasibility of using a Heliospheric
Imager (HI) instrument, such as STEREO/HI, for unambiguously connecting
remote images to in situ observations of coronal mass ejection (CMEs).
Our long-term goal is to develop and test methods to predict CME
parameters from heliospheric images, suitable for real-time operational
space weather forecasting. We do this with an eye on future missions,
for example Solar Orbiter, when it is in a suitable position with
respect to the Sun-Earth line, or for a dedicated space weather mission
at the L5 point in the Sun-Earth system (e.g. EASCO mission concept).
We compare the predictions for speed and arrival time
for about 20 CME events, each observed remotely by one STEREO
spacecraft, to the speed and arrival time observed at various in situ
observatories. We use "geometrical modeling", which means we
approximate the CME fronts with various shapes (Fixed-Phi, Harmonic
Mean (HM), Self-Similar Expansion (SSE)). These models are fitted to
the time-elongation functions extracted from STEREO/SECCHI images with
the SolarSoft SATPLOT package. We use these techniques for a
single-spacecraft HI observer, and consequently assume constant CME
speed and direction. For assessing the accuracy of the parameters
derived from HI we look at plasma and magnetic field data of
interplanetary CME sheath regions by Wind (MFI, SWE instruments) and
STEREO-A/B (IMPACT, PLASTIC), all located close to 1 AU. The results
show that the arrival times derived from imaging generally closely
match the in situ ones to within roughly 6 hours, and speeds agree to
within 200 km/s for slow CMEs. However, for very fast CMEs in the range
> 1500 km/s, the predicted speeds are too high by up to 1000 km/s,
even though we include effects caused by the ICME flank, which moves
slower than the apex in the HM and SSE models. This calls for an update
of these methods to include deceleration, if they want to be
successfully used to predict the fastest and potentially most
geoeffective CMEs from outside the Sun-Earth line.
This work has received funding from the European Commission FP7 Project COMESEP (263252).
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Verification of Solar Microwave Precursors of Geoeffective Coronal Mass Ejections
Sheiner, Olga; Fridman, Vladimir; Ledaschev, Sergey
Radiophysical Research Institute, RUSSIAN FEDERATION
It has been shown that a significant number of coronal mass
ejections in a two-hour interval before their recording by coronagraphs
are preceded by sporadic radio emission that can be defined as radio
precursors of coronal mass ejections.
The results of statistical studies evidence that the
width of the most developed CMEs affecting the near-Earth space depends
on the characteristics of microwave sporadic radio emission observed
during two-hour intervals preceding CME registration on coronagraph. It
was shown also that the absolute majority of such CMEs an the stage of
their formation is associated with sporadic microwave radiation having
the certain characteristics, such as its broadband and time duration of
more than 10 minutes. This allows to assess potential geoeffectiveness
of CMEs using data on the radio emission, taking into account expected
CME source position on the solar disk.
The verification of geoeffective CMEs forecast is carried out on the base of SOHO/LASCO data.
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SuperDARN HF Radar Data Coverage for Ionospheric Electric Field Measurement
Chisham, Gareth; Freeman, Mervyn; Kavanagh, Andrew
British Antarctic Survey, UNITED KINGDOM
Specification of the ionospheric electric field, and its
extension into the magnetosphere, is of fundamental value to many space
weather research problems, and will be essential to assimilate into
whole atmosphere, magnetospheric, and radiation belt models now under
development for space weather forecasting. To this end, we analyse the
data coverage provided by the Super Dual Auroral Radar Network
(SuperDARN) which currently comprises 33 radars around the world and
has data going back over 20 years from some radars. We compare the
coverage with the observing goals set by the World Meteorological
Organisation and that needed by current models and identify the main
factors influencing coverage.
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4 |
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Investigation of Ionospheric and Magnetospheric Processes using High Frequency Induction Coil Magnetometers in the UK
Beggan, Ciaran; Kelly, Gemma; Thomson, Alan
British Geological Survey, UNITED KINGDOM
In June 2012, the British Geological Survey Geomagnetism team
installed two high frequency (100 Hz) induction coil magnetometers at
the Eskdalemuir Observatory, in the Scottish Borders of the United
Kingdom. The induction coils permit us to measure the very rapid
changes of the magnetic field.
We present initial results from first year of data.
Analysis of spectrograms and power spectral density plots in the
frequency band of 3-40 Hz from the coils show diffuse bands of peak
power around 7.8 Hz, 14.3 Hz, 20.8 Hz, 27 Hz, 34 Hz and 39Hz related to
the global Schumann resonances. We also detect a strong narrow peak at
25 Hz, which is a harmonic of the UK electrical power system.
There are a number of features in the data of
interest, such as intermittent variation of the Schumann resonance
harmonics and magnetospheric pulsations. The data are freely available
on request to the community.
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Geomagnetic Conditions Forecasting by using Solar Activity Parameters
Gerontidou, Maria; Paouris, Evangelos; Paschalis, Pavlos; Papaioannou, Athanasios; Mavromichalaki, Helen
National and Kapodistrian University of Athens, GREECE
Enhancements of geomagnetic activity resulted from the
interaction of solar wind originated from solar flares, coronal mass
ejections and coronal holes at the Earth magnetosphere have been
studied in the frame of Space Weather. The space weather effects can
roughly be divided into two categories: those effects quickly and
directly associated with solar activity, and those effects resulting
from the impact of solar activity-generated interplanetary coronal mass
ejections on Earth's magnetosphere. The scientific community managed to
implement centers for the continuous monitoring of the geomagnetic
conditions which resulted into short and long term forecasting of the
planetary geomagnetic activity such as Ap index. A new forecasting
center at the Athens Neutron Monitor Station (A.Ne.Mo.S) has been
established from 2012. A first estimation of the accuracy of the
predicted Ap index which provided by the Athens Forecasting Center is
calculated about 82% during the first year of its operation. In this
work a statistical treatment of crucial parameters of about 119 X-Ray
flares and 1408 M-class flares as well as their associated coronal mass
ejections during the time period 2000-2012 has been performed. These
results have been used in order to have a first estimation of the
geomagnetic Ap index. This method has been applied on the Space Weather
Forecasting Center of University of Athens and these results are
briefly discussed.
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The Spatial and Temporal Distribution of Solar and Galactic Cosmic Rays
Shatov, Pavel1; Tasenko, Sergey1; Skorohodov, Ilya1; Getselev, Igor1; Podzolko, Mikhail1; Anashin, Vasily2; Protopopov, Grigory2
1Fiodorov Institute of applied geophysics, RUSSIAN FEDERATION;
2Institute of Space Device Engineering, RUSSIAN FEDERATION
The areas of energy particles on the Sun from 1956 to 2012 are
considered. The significant irregularity of their distribution is
registered.
The ranges of longitudes, in which particles are
considerably injected, are discovered. The areas of the Sun with very
law radiation effectiveness are at particular interest. The deficiency
of the solar proton events during the inversion period of the Earth's
main magnetic field is noticed. The one made a conclusion about the
obtained data reasonability for estimation of the observation
probability and solar cosmic ray appearance risk.
For the estimation of the charged particle
contribution, going from the interplanetary space on the measuring
instruments, the data base on cosmic rays is created. It includes
maximum, minimum and average values of proton fluence from 1 month to
10 years space of time.
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Variability of the Main Ionospheric Parameters during Magnetic Storm Recovery Phase
Buresova, Dalia; Lastovicka, Jan; Boska, Josef; Novotna, Dagmar
Institute of Atmospheric Physics AS CR, CZECH REPUBLIC
Intensive ionospheric research, numerous multi-instrumental
observations and large-scale numerical simulations of ionospheric
response to magnetic storm-induced disturbances during the last several
decades were primarily focused on the storm main phase, in most cases
covering only a few hours of the recovery phase following after storm
culmination. Ionospheric behaviour during entire recovery phase still
belongs to not sufficiently explored and hardly predictable features.
In general, the recovery phase is characterized by an abatement of
perturbations and a gradual return to the "ground state" of ionosphere.
However, observations of stormy ionosphere show significant departures
from the climatology also within this phase. This paper deals with the
quantitative and qualitative analysis of variability of the main
ionospheric parameters during magnetic storm recovery phase over middle
latitudes and under high and low solar activity conditions for nowadays
and future modelling and forecasting purposes. We compared critical
frequencies, peak heights and TEC observed during recovery phase with
the corresponding outputs of the IRI and NeQuick models.
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3D CME Parametrization - Comparison of GCS and CAT Techniques and ENLIL Applications
Bosman, Eckhard1; Bothmer, Volker1; Millward, George2; Venzmer, Malte1; Odstrcil, Dusan3
1Institute for Astrophysics, Georg-August-University Göttingen, GERMANY;
2National Oceanic and Atmospheric Administration (NOAA), Space Weather Prediction Center (SWPC), Boul, UNITED STATES;
3NASA/GSFC Goddard Space Flight Center, Greenbelt, Maryland, USA, UNITED STATES
Since launch of the STEREO twin spacecraft in October 2006, 1071 large-scale CMEs were identified
in STEREO/SECCHI/COR2 observations between January
2007 and December 2011 covering the full range of spacecraft separation
angles between 0 and 180 degrees. Based on their bright and clear
white-light appearance in the COR 2 field of view 242 CMEs were
selected and analyzed with the Graduated Cylindrical Shell (GCS)
modeling technique developed by Thernisien, Vourlidas and Howard. For a
set of selected modeled CMEs their 3D topology, direction of
propagation and speed was analyzed based on multipoint observations
(STEREO, SOHO) with the CME Analysis Tool (CAT) developed by Millward
et al. at the Space Weather Prediction Center, Boulder, CO, and with
the GCS model. The analyzed events comprise earthward directed CMEs of
low (~300 km/s), medium (~600 km/s) and high (>1.000 km/s) speed
observed by STEREO and SOHO under various viewing angles. The results
from the modeling comparison provide important implications for the use
of CME parameters as input for ENLIL simulations yielding CME arrival
times and 1 AU CME speeds.
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Accuracy Assessment of the Space Weather Aspects Forecasts used in the Russian Federal Space Agency Monitoring System
Anashin, Vasily1; Protopopov, Grigory1; Gaidash, Sergey2; Belov, Anatoly2
1Institute of Space Device Engineering, RUSSIAN FEDERATION;
2Pushkov institute of terrestrial magnetism, ionosphere and radio wave propagation (IZMIRAN), RUSSIAN FEDERATION
The Russian Federal Space Agency Monitoring system of space
radiation exposure on spacecraft electronic equipment elements were
developed by the Institute of space device engineering and operates
successfully.
The Monitoring System covers two parts: the scientific
monitoring system (ground-based segment) and the engineering monitoring
system (space-born segment). The ground-based segment comprises
forecast station that provides the following daily forecasts and alerts:
- Geomagnetic activity forecast for 1 - 3 days;
- Geomagnetic activity forecast for 6 - 8 days;
- Daily GSO high energy electron fluence forecast for 27 days;
- Space weather review and forecast, covering solar proton increasing forecast;
- Proton events alert;
- GSO high energy electron fluence increasing alert (electronic equipment killers).
Efficiency and accuracy are the major criteria of
performance forecast usage. Forecasts are made promptly owing to
round-the-clock space weather characteristics monitoring and use of
modern communication facilities.
The paper presents accuracy assessment of the given
forecasts which were made by forecast correlation analysis with the
measured values in various time intervals. These estimations were
correlated with the similar results from the world forecast centers.
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Comparison of Thermospheric Data Assimilation with a Drag Temperature Model for Operational Nowcasting and Forecasting.
Murray, Sophie A.1; Henley, Edmund M.1; Jackson, David L.1; Bruinsma, Sean L.2
1Met Office, UNITED KINGDOM;
2CNES, FRANCE
The thermosphere hosts thousands of low-earth-orbit objects,
including operational satellites. In addition to regular patterns,
local variations of drag forces can be induced in the wake of intense
solar activity. Accurate orbit prediction is thus imperative to keep
satellites operational. The work of the Advanced Thermospheric
Modelling for Orbital Prediction FP7 project aims to improve upon
current semi-empirical models used for prediction in order to enable
accurate forecasting.
A thermospheric data assimilation procedure has been
developed using general circulation models (such as the Coupled Middle
Atmosphere-Thermosphere model, and the
Thermosphere-Ionosphere-Electrodynamics General Circulation Model) with
inferred neutral densities from satellite observations (e.g., from
CHAMP, GRACE, and GOCE). Data assimilation results were compared with
the outputs of an advanced semi-empirical drag temperature model (DTM)
that uses proxies to describe the solar and geomagnetic forcing of the
thermosphere, as well as some corrections from observations.
Independent observations from periods at solar maximum (2002) and solar
minimum (2009) were also used for inter-comparison with analyses and
forecasts from the two approaches. The results of this work will allow
schemes to be developed for near-real-time assimilation of
thermospheric data into the predictive DTM and physical models,
ultimately enabling near-real-time modelling.
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The Polar Cap (PC) Index and Power Grid Disturbances.
Stauning, Peter
Danish Meteorological Institute, DENMARK
The strong geomagnetic storm in the evening of 30 October 2003
caused high-voltage power grid disturbances in Sweden that expanded to
produce hour-long power line outage in Malmoe located in the southern
part of the country. Similar events have occurred earlier, among
others, during the great storms of 13 - 14 July 1982, 8 - 9 February
1986, and 13 March 1989. Most cases of space weather related power grid
disturbances are caused by extraordinarily intense substorm events.
Such events may have a sudden onset but are usually preceded by lengthy
intervals of very high values of the Polar Cap (PC) index. The PC index
monitors the transpolar convection of plasma and magnetic fields
building the stresses in the magnetospheric tail region that are
released in strong substorms. During the 30 October 2003 event the
intense solar proton radiation disabled the ACE satellite observations
widely used to provide forecast of magnetic storm events. Hence in this
case the alarmingly high PC index could provide useful warning of the
storm in back-up of the missing ACE-based forecast. In further cases,
on-line monitoring of the PC index could provide alternative or
supplementary magnetic storm and substorm warnings to the benefit of
power grid operators.
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Differences of Slow and Fast Solar Wind Stream Effects on the Earth Foreshock: THEMIS Observations
Urbar, Jaroslav
Czech Space Office, CZECH REPUBLIC
We provide the foreshock model of plasma parameter
modification based both on magnetic fluctuations and energetic particle
fluxes.
In the statistical study, we separate effects of the slow and fast
solar wind streams on the foreshock region. We use
multi-point observations from the THEMIS-ARTEMIS mission and compare to
WIND solar wind monitor, estimating evolution of solar wind during
interactions in the
foreshock. We evaluate the differences emerging from
the fast or slow solar wind streams, taking advantage of the recent
prolonged solar minima. Most studies of the solar wind-magnetosphere
interaction rely on L1 observations that are propagated toward the
Earth assuming negligible evolution of upstream parameters along the
solar wind path and not taking proper account on the different
instrumentation and measurement modes being used. We quantify the
effect of a systematic deceleration of the average solar wind speed
with a decreasing distance to the bow shock that is controlled by the
level of magnetic field fluctuations and by the flux of reflected and
accelerated particles in the foreshock region with evaluating the
established physical mechanisms. We show that the reflected particles
not only excite the waves of large amplitudes but also modify mean
values of either fast or slow solar wind parameters measured either in
the foreshock or in an un-perturbed solar wind within broad range of
Mach
numbers.
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Modeling of Severe Geomagnetic Storms of Solar Cycle 23
Revallo, Milo¨1; Valach, Fridrich2; Hejda, Pavel3; Bochníček, Josef3
1Geophysical Institute of the Slovak Academy of Sciences, Bratislava, SLOVAKIA;
2Geomagnetic Observatory, Geophysical Institute of the Slovak Academy of Sciences, Bratislava, SLOVAKIA;
3Institute of Geophysics, Academy of Sciences of the Czech Republic, Prague, CZECH REPUBLIC
We try to model selected strong geomagnetic storms of solar
cycle 23 using a logistic regression model combined with an empirical
model of the solar wind magnetosphere interaction. The set of solar
wind data obtained from the ACE satellite is considered and the
corresponding geomagnetic response is modeled and compared with real
data. The discontinuity in magnetic field at the magnetopause is shown
to play a key role in this study. The geomagnetic response is evaluated
using the scale: no response, weak, medium and strong response,
respectively. The question is how much past solar wind data is needed
to obtain the most accurate one step ahead forecasts. We compare the
current approach based on logistic regression with the method of
artificial neural networks used in our previous study.
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TEC Mapping and Short Time Forecast
Pozoga, Mariusz; Tomasik, Lukasz; Dziak-Jankowska, Beata; Stanislawska, Iwona
Space Research Centre, POLAND
GNSS permanent station are valuable source data for TEC
mapping. In this work we presents maps and short time forecast of TEC
valule over Europe region. For this purposes we have tested universal
kriging and autocovariance for forecast. Using historical data we test
our method for quite and disturb space weather conditon.
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The EISCAT_3D Science Case
Tjulin, Anders1; Mann, Ingrid1; McCrea, Ian2; Aikio, Anita3; Ulich, Thomas4
1EISCAT Scientific Association, SWEDEN;
2STFC Rutherford Appleton Laboratory, UNITED KINGDOM;
3University of Oulu, FINLAND;
4Sodankylä Geophysical Observatory, FINLAND
The EISCAT_3D radar system will be a world-leading
international research infrastructure located in the Fenno-Scandinavian
Arctic, using the incoherent scatter technique to study geospace and to
investigate how the Earth's atmosphere is coupled to space. The
EISCAT_3D phased-array multistatic radar system will be operated by
EISCAT Scientific Association and thus be an integral part of an
organisation that has successfully been running incoherent scatter
radars for more than thirty years.
The baseline design of the radar system contains a
core site with transmitting and receiving capabilities located close to
the intersection of the Swedish, Norwegian and Finnish borders and five
receiving sites located within 50 to 250 km from the core. The
EISCAT_3D project is currently in its EU FP7 funded Preparatory Phase
and can smoothly transit into implementation in 2014, provided
sufficient funding. Construction would then start in 2016 and first
operations in 2018.
The EISCAT_3D Science Case is prepared as part of the
Preparatory Phase. It is updated annually with new releases, and it
aims at being a common document for the whole future EISCAT_3D user
community. The areas covered by the Science Case are atmospheric
physics and global change; space and plasma physics; solar system
research; space weather and service applications; and radar techniques,
new methods for coding and analysis.
Although incoherent scatter radars, such as EISCAT_3D,
are few in number, the power and versatility of their measurement
technique mean that they can measure parameters which are not
obtainable otherwise, and thus also be a cornerstone in the
international efforts to measure and predict space weather effects.
Accordingly, the incoherent scatter data is also useful for
verifications of space weather forecast.
Two of the other aims for EISCAT_3D are to understand
the ways the natural variability in the upper atmosphere, imposed by
the Sun-Earth system, can influence the middle and lower atmosphere,
and to improve the predictivity of atmospheric models by providing
higher resolution observations to replace the current parametrised
input. The EISCAT_3D observations will also be used to monitor the
direct effects from the Sun on the ionosphere-atmosphere system and
those caused by solar wind magnetosphere-ionosphere interaction. In
addition, EISCAT_3D will be used for remote sensing the large-scale
behaviour of the magnetosphere from its projection in the high-latitude
ionosphere.
EISCAT_3D can also be used to study solar system
properties. Thanks to the high power and great accuracy, mapping of
objects like the Moon and asteroids is possible. With the high power
and large antenna aperture, incoherent scatter radars can be
extraordinarily good monitors of extraterrestrial dust and its
interaction with the atmosphere.
Finally, over the years the EISCAT radars have served
as a testbed for new ideas in radar coding and data analysis. EISCAT_3D
will be the first of a new generation of "software radars" whose
advanced capabilities will be realised not by its hardware but by the
flexibility and adaptability of the scheduling, beam-forming, signal
processing and analysis software used to control the radar and process
its data. Thus, new techniques will be developed into standard
observing applications for implementation in the next generation of
software radars.
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Activities at SANSA Space Weather Centre
Nxele, Teboho; Tshisaphungo, Mpho; McKinnell, Lee-Anne; Wentworth , Laura
South African National Space Agency, SOUTH AFRICA
The South African National Space Agency (SANSA) operates the
Regional Warning Center (RWC) for Space Weather in Africa. The RWC is
located within the Space Science Directorate of SANSA in Hermanus,
South Africa. SANSA Space Science is a research facility for Space
Science in South Africa, and operates a Space Weather Unit within its
Research Group. The combination of ground and satellite based data is
piped into the centre for predictions and forecasts analysis. This
paper will outline the prediction and forecast procedures applied at
the centre, present the measurements that are available for use by the
center, and look at the applications that are currently being served
within South Africa.
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Validation of the DIAS TEC Maps developed with the TaD Topside Profiler
Belehaki, Anna1; Tsagouri, Ioanna1; Tziotziou, Kostas1; Kutiev, Ivan2; Marinov, Pencho2; Bergeot, Nicolas3; Chevalier , Jean Marie3
1National Observatory of Athens, GREECE;
2Bulgarian Academy of Sciences, BULGARIA;
3Royal Observatory of Belgium, BELGIUM
TaD is a topside model that extrapolates the electron density
profile up to 20,000 km retrieving Digisonde characteristics at hmF2
and TEC estimates from GNSS receiver co-located with Digisonde. The TaD
is based on the Topside Sounders Model (TSM), which is a set of
empirical functions for the O+/H+ transition height (hT), the topside
electron density scale height (HT), and their ratio, derived from the
Alouette/ISIS topside soundings. To further increase the TSM accuracy,
analytical formulas were developed for obtaining the shape of the
vertical plasma distribution in the topside ionosphere and plasmasphere
based on TSM parameters. This profiler models separately the O+ and H+
density profiles. To obtain the density distribution, the profiler
needs specification of the F layer maximum density (NmF2), its height
(hmF2) and its scale height (Hm) at its lower boundary. These are
obtained from Digisonde measurements which are ingested to the TaD for
the reconstruction of the electron density profile from the F layer
peak to GNSS orbits. Above the transition height, the model calculates
in addition to the other species, the distribution of He+, extracted
from the analysis of the electron density profiles from ISIS-1. The
plasmaspheric scale height is approximated as a function of altitude,
latitude, local time, and season using an optimization procedure to
achieve best fit with the measured profiles.
A major problem that had to be resolved in order to
implement the model in the DIAS environment, had to do with the
accuracy of the autoscaled scale height at the hmF2, provided by the
Digisondes. This was very often out-of-range, leading to unrealistic
results for the modeled electron density profile. Therefore, the TEC
parameter calculated from TaD model was adjusted with the TEC parameter
calculated by GNSS transmitting RINEX files provided by receivers
co-located with the Digisondes. This adjustment forces the model to
correctly reproduce the topside scale height, despite the inaccurate
values of Hm, and it is therefore very important for the application of
TaD in an operational environment, such as the DIAS system. Based on
this latest version of the TaD model, the DIAS system calculates maps
of TEC over Europe, using (1) autoscaled bottomside electron density
profiles from 8 European Digisondes and (2) TEC parameters at the
Digisondes locations extracted from the ROB GNSS-based TEC maps over
Europe. These maps are released in near-real time at 15 minutes
resolution since November 2012.
In this paper we present the validation of the maps,
including the control for internal consistency of the model and the
comparison of modeled TEC values with independent data. The validation
extends to quiet and to geomagnetic storm intervals. First results show
a reasonable agreement between TEC maps derived with TaD and other
regional and global maps collected over a period of 6 months, with a
maximum discrepancy of 3 TECU for the 96% of the cases, depending on
the latitude of the geographic location under consideration. Based on
this analysis, it is possible to reach conclusions about the parameters
that affect the quality of the maps, i.e. the number of Digisondes
contributing with data to each specific map, their geographic
distribution, and the accuracy of the Digisonde autoscaled values.
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LDi: A Local Disturbance Index for Space Weather Purposes
Palacios, Judith; Guerrero, Antonio; Saiz, Elena; Cid, Consuelo; Cerrato, Yolanda
University of Alcala, SPAIN
Real time monitoring of geomagnetic field is relevant for
space weather purposes. Although some geomagnetic indices as Dst, ap or
Kp are estimated in real time as proxies of global magnetic activity,
in some cases, as GICs, local geomagnetic disturbances better comply
with the phenomena than with the global ones. As a consequence, local
magnetic activity timely available is essential for accurate
forecasting of this kind of events. In this work a new index is
proposed: the 'Local Disturbance index', i.e., an index (i) with local
(L) information of the disturbance (D) during the storm time, obtained
from the H component of geomagnetic field measured at a determined
observatory.
The requirements for a real time index for Spain guide
us also to compare data recorded at three magnetic observatories (SPT,
EBR and GUI) spread in longitude and latitude, looking for a
relationship among them with the aim of providing a national local
disturbance index. The results of this study are shown in this
presentation.
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Comparison of EnOI Data Assimilation into Two Physical Models of the Thermosphere
Henley, Edmund; Murray, Sophie A.; Jackson, David R.
Met Office, UNITED KINGDOM
The ATMOP project (www.atmop.eu) aims to improve orbital
predictions for satellites close to Earth, through improved predictions
of space weather effects on the thermospheric density responsible for
the drag on the LEO satellites.
A key part of ATMOP is using a physics-based model, as
a complement to the semi-empirical DTM model used operationally.
Specifically, we have worked on building data assimilation systems,
using in situ density observations, such as those from the CHAMP
satellite, to constrain the model density predictions, bringing them
closer to the observed density values.
Here we compare the results of assimilating
observations into two different physical models: UCL's CMAT2 model and
NCAR's TIEGCM model. Both simulate the thermosphere-ionosphere region,
but differ in some details. The assimilation is performed using an
ensemble optimal interpolation (EnOI) scheme, and the forecast results
from both models are compared to observations not included in the
assimilation.
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On the Present Status of Solar Activity
Brajsa, Roman1; Verbanac, Giuli2; Sudar, Davor3; Skokic, Ivica4; Hanslmeier, Arnold5; Woehl, Hubertus6; Roth, Markus7; Ludmany, Andras8; Murakozy, Judit8; MacLeod, Chelsea L.9; Ivezic, Zeljko10; Mursula, Kalevi11; Zhang, Liyun11
1University of Zagreb, Faculty of Geodesy, CROATIA;
2Faculty of Science, University of Zagreb, CROATIA;
3Faculty of Geodesy, University of Zagreb, CROATIA;
4Cybrotech Ltd, Zagreb, CROATIA;
5IGAM, Institute of Physics, University of Graz, AUSTRIA;
6Kiepenheuer-Institut fuer Sonnenphyisk, Freiburg, GERMANY;
7Kiepenheuer-Institut fuer Sonnenphysik, Freiburg, GERMANY;
8Heliophysical Observatory, Debrecen, HUNGARY;
9Physics Department, USNA, Annapolis, UNITED STATES;
10Department of Astronomy, Univ. of Washington, Seattle, UNITED STATES;
11Department of Physics, University of Oulu, FINLAND
The amplitude and time for the actual solar cycle maximum are
predicted using different methods:
(i) asymmetry method
(ii) correlation between relative sunspot numbers in minimum and maximum
(iii) autoregressive moving average model (ARMA)
(iv) damped random walk model (DRW)
(v) connection between the starting latitudes and amplitudes of solar cycles
(vi) relation between the number of spotless days and the subsequent amplitude
(vii) Waldmeier effect: a relation between the rising time and maximum amplitude.
Now it is already clear that the maximum of the 24th solar cycle will be weaker
than the previous one. The estimated time of the maximum is in the years
2013-2014. Several data sets, including those from SIDC, ROB, Greenwich and
Debrecen are used.
Finally, the nonlinear effects of the solar activity and its
influence on the prediction possibilities on short and long temporal scales
will be briefly discussed.
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A prototype of a quick Information System for Space Weather Events effects on the ionosphere.
Herraiz, Miguel1; Moreno-Monge, Beatriz2; Rodriguez-Bouza, Marta2; Rodriguez-Bilbao, Izarra2; Rodriguez-Caderot, Gracia2; Radicella, Sandro Maria3
1Universidad Complutense de Madrid, Instituto de Geociencias, SPAIN;
2Universidad Complutense de Madrid, SPAIN;
3Telecommunications/ICT Development Laboratory (T/ICT4D) Abdus Salam International Center for Theoret, ITALY
In this poster we present a prototype of a quick Information
System aimed at warning about the ionospheric effects following a
geomagnetic storm and based on the daily analysis of the behaviour of
the ionosphere. After receiving a warning message from the different
Space Weather Forecast Centres, as British Geological Survey and NOAA
Space Weather, the System analyses a representative sample of
ionospheric information and produces a new warning message if a
ionospheric storm is detected. In this way, positioning and navigation
can be more realistically calculated.
For the analysis of the ionospheric state the
prototype uses RINEX files from 5 International GNSS Service stations
belonging to the International GPS Service network located on the South
of Europe and the North of Africa. The data are obtained at 30 seconds
sampling rate for the ten days previous to the day studied. This RINEX
files are processed with a calibration algorithm developed at the
Istituto di Fisica Applicata "Nello Carrara" of Florencia and the Abdus
Salam International Center for Theoretical Physics of Trieste. This
processing technique assumes the ionospheric thin shell model to obtain
vertical total electron content (vTEC) from slant total electron
content (sTEC) at the Ionospheric Pierce Point, IPP. The vTECmean
obtained from the vTEC values of the 10 previous days is used to
calculate the relative vTEC values that inform about on the changes in
the ionosphere. When the values are higher than 50% or below -50% the
prototype detects and anomaly and issues a message.
We also present the first test of our system using
five past alerts and known geomagnetic storms; four occurred in 2012
and one in 2011.
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