G. Souvatzoglou

Monitoring and forecasting of great solar proton events using the neutron monitor network in real time

Obtaining online information on the onset of great solar energetic particle (SEP) events from real-time data of the neutron monitor network (NMN) is considered and the corresponding algorithm and program are proposed. Determination of the particle energy spectrum outside the atmosphere at different moments of the flare is considered on the basis of coupling functions method. The spectra defined in diffusion and kinetic approaches are compared. Using this information, the time of the SEP ejection into solar wind, the energy spectrum of a SEP event in the source inside the solar corona, and the SEP diffusion coefficient in the interplanetary space during the flare can be estimated. In this work, the significant possibility of the expected SEP fluxes and the energy spectrum forecasting on the early part of the increasing SEP intensity (about 20-30 min after the onset) is considered. Available satellite data in real-time scale combined with real time-data from neutron monitors (NM) are used for extrapolation of this forecast to the region of very small energy particles. The method is checked on the SEP event of September 1989. It is important to note that the accuracy of the developed method sufficiently increases with the increasing dangerous level of the SEP event. The method is not CPU damaging and can run in real time, providing inexpensive means of SEP prediction.

Optimizing the real-time ground level enhancement alert system based on neutron monitor measurements: Introducing GLE Alert Plus

Whenever a significant intensity increase is being recorded by at least three neutron monitor stations in real-time mode, a ground level enhancement (GLE) event is marked and an automated alert is issued. Although, the physical concept of the algorithm is solid and has efficiently worked in a number of cases, the availability of real-time data is still an open issue and makes timely GLE alerts quite challenging. In this work we present the optimization of the GLE alert that has been set into operation since 2006 at the Athens Neutron Monitor Station. This upgrade has led to GLE Alert Plus, which is currently based upon the Neutron Monitor Database (NMDB). We have determined the critical values per station allowing us to issue reliable GLE alerts close to the initiation of the event while at the same time we keep the false alert rate at low levels. Furthermore, we have managed to treat the problem of data availability, introducing the Go-Back-N algorithm. A total of 13 GLE events have been marked from January 2000 to December 2012. GLE Alert Plus issued an alert for 12 events. These alert times are compared to the alert times of GOES Space Weather Prediction Center and Solar Energetic Particle forecaster of the University of Malaga (UMASEP). In all cases GLE Alert Plus precedes the GOES alert by ≈8–52 min. The comparison with UMASEP demonstrated a remarkably good agreement. Real-time GLE alerts by GLE Alert Plus may be retrieved by http://cosray.phys.uoa.gr/gle_alert_plus.html, http://www.nmdb.eu, and http://swe.ssa.esa.int/web/guest/space-radiation. An automated GLE alert email notification system is also available to interested users.

Space weather forecasting at the new Athens center: the recent extreme events of January 2005

From the beginning of this year a new data analysis center [Athens Neutron Monitor Data Processing (ANMODAP) Center] is operated in Athens University producing a real-time prediction of space weather phenomena. At this moment there has been a multi-sided use of twenty-three neutron monitors providing real-time data on the Internet. Moreover, interplanetary space parameters data from Geostationary Orbiting Environmental Satellite and Advanced Composition Explorer (ACE) satellite are also collected in this center. The ANMODAP Center in real-time is of high potential interest, as it is expected to give alerts for ground level enhancements (GLEs) of solar cosmic rays (CRs) and geomagnetic storms and therefore to provide crucial information for Space Weather applications. Forecasting of the last GLE and the geomagnetic variations of CRs on January 2005, is presented.

ALERT SYSTEM FOR GROUND LEVEL COSMIC-RAY ENHANCEMENTS PREDICTION AT THE ATHENS NEUTRON MONITOR NETWORK IN REAL-TIME

The prediction of solar activity is important for various technologies, including operation of low-Earth orbiting satellites, electric power transmission grids, high-frequency radio-communications etc. The Athens Neutron Monitor Network in Real Time, initiated in December 2003, provides data from twenty-one real-time neutron monitor stations, useful for real-time monitoring of cosmic particle fluxes. Recently a program for forecasting the arrival of dangerous middle energy particles on the Earths surface has started. These program processes the data taken from the Neutron Monitor Network and informs us about the onset of ground level enhancements. In this way enough time to protect technological systems will be given.

COSMIC RAY EVENTS RELATED TO SOLAR ACTIVITY RECORDED AT THE ATHENS NEUTRON MONITOR STATION FOR THE PERIOD 2000–2003

In this work a complete study of 359 solar flares, 111 Halo coronal mass ejections (Halo CMEs) and 45 Partial Halo events occurred from November 2000 to November 2003, is considered. This time period characterized by an unexpected activity of the Sun, was divided into 27-day intervals starting from Bartels Rotation No. 2284 (14.10.2000) to No. 2324 (25.11.2003), generating diagrams of the cosmic ray intensity data recorded at the Athens Neutron Monitor Station. On these qualitative data presented for the first time, a mapping of all available solar and interplanetary events, such as solar flares with importance C, M and X, coronal mass ejections (Halo and Partial) was done. The existence of a connection between solar flares with CMEs and the respective connection to the Forbush effects on yearly and monthly basis are discussed. The role of extreme solar events occurred in March-April 2001 and in October-November 2003 is also considered.

Recent Research applications at the Athens Neutron Monitor Station

The ground based neutron monitor measurements play a key role in the field of space physics, solar-terrestrial relations, and space weather applications. The Athens cosmic ray group has developed several research applications such as an optimized automated Ground Level Enhancement Alert (GLE Alert Plus) and a web interface, providing data from multiple Neutron Monitor stations (Multi-Station tool). These services are actually available via the Space Weather Portal operated by the European Space Agency (http://swe.ssa.esa.int). In addition, two simulation tools, based on Geant4, have also been implemented. The first one is for the simulation of the cosmic ray showers in the atmosphere (DYASTIMA) and the second one is for the simulation of the 6NM-64 neutron monitor. The contribution of the simulation tools to the calculations of the radiation dose received by air crews and passengers within the Earths atmosphere and to the neutron monitor study is presented as well. Furthermore, the accurate calculation of the barometric coefficient and the primary data processing by filtering algorithms, such as the well known Median Editor and the developed by the Athens group ANN Algorithm and Edge Editor which contribute to the provision of high quality neutron monitor data are also discussed. Finally, a Space Weather Forecasting Center which provides a three day geomagnetic activity report on a daily basis has been set up and has been operating for the last two years at the Athens Neutron Monitor Station.

The new Athens Center applied to Space Weather Forecasting

The Sun provides most of the initial energy driving space weather and modulates the energy input from sources outside the solar system, but this energy undergoes many transformations within the various components of the solar‐terrestrial system, which is comprised of the solar wind, magnetosphere and radiation belts, the ionosphere, and the upper and lower atmospheres of Earth. This is the reason why an Earth’s based neutron monitor network can be used in order to produce a real time forecasting of space weather phenomena.Since 2004 a fully functioned new data analysis Center in real‐time is in operation in Neutron Monitor Station of Athens University, (ANMODAP Center) suitable for research applications. It provides a multi sided use of twenty three neutron monitor stations distributing in all world and operating in real‐time given crucial information on space weather phenomena. In particular, the ANMODAP Center can give a preliminary alert of ground level enhancements (GLEs) of solar cosmic rays which ca...

A Study for an Unmanned Aerial Vehicle carrying a radiation spectrometer networked to the new Athens Center active in Space Weather Events forecasting

A proposal is presented for flying a light Unmanned Aerial Vehicle (UAV) carrying a Linear-Energy-Transfer (LET) radiation spectrometer and networked to the Athens Neutron Monitor Data Processing Center (ANMODAP), active in Space Weather Events (SWE) forecasting. The ANMODAP receives data from a large number of remote neutron monitor (NM) stations, provided in real time over the Internet, together with satellite data. Through this project, the ANMODAP forecasting capability will be increased with the collection of data at high atmospheric altitudes over Greece by the LET radiation spectrometer, carried on the specially designed UAV. The advantages of this spectrometer are its very small dimensions, light weight, and low power consumption. The UAV, powered from photovoltaic generators, flying at high altitudes with propellers on small electrical motors, and carrying simple networking equipment, will achieve long range telecommunication links with a terrestrial footprint larger than the area of Greece.