Session 14 - Space weather applications of global neutron monitor network

Alexander Mishev (ReSolve University of Oulu)
Friday 18/11, 10:00-12:00
Mercator

The world wide neutron monitor (NM) network provide continuous records of cosmic ray (CR) variations. Over the years it have been the main multi-instrument tool for the analysis of ground level enhancements (GLEs). Nowadays, the majority of the existing NMs are included in a database, neutron monitor database (NMDB), which provides information practically in a real time. This allows the community to develop and/or to enhance methods for now cast or/and forecast of space weather events. At present a progress of modeling related to both application of NM for GLE analysis as well space weather is achieved.

The session is devoted to recent works related to all aspects of space weather. Focus will be given in modeling aiming the now cast of aircrew dose exposure, specifically during GLEs. Progress reports of modeling of particle propagation in the Earth atmosphere and magnetosphere towards space weather applications are welcome. Comparison of recent models with experimental results are very welcome.

The usage and comparison of the global NM network within satellite-born instruments as well as other ground based, which provide complementary information to NM data are relevant to this session.

Reports of enhancement future projects related to space weather and application of the existing NM network are also welcome.

Poster Viewing
Friday November 18, 10:00 - 11:00, Poster Area

Talks
Friday November 18, 11:00 - 12:00, Mercator

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Talks : Time schedule

Friday November 18, 11:00 - 12:00, Mercator

11:00	Current status and perspectives of NMs for space weather	Bütikofer, R et al.	Invited Oral
	Rolf Bütikofer
	Physikalisches Institut, University of Bern and High Altitude Research Stations Jungfraujoch and Gornergrat
	The worldwide network of ground-based neutron monitors (NMs) measures the secondary cosmic rays, i.e. the product of the collisions of primary cosmic rays with the molecules in the Earth's atmosphere. Currently, the measurements of many of these NMs are stored in the NM database “NMDB” in real-time. The possibility to have the data-set from a single place in real-time enables the linked NM data to provide a significant instrument for space weather forecasting or nowcasting. There are mainly two domains where NM measurements may play an important role in space weather applications: arrival of energetic solar cosmic ray particles at the Earth during so-called Ground Level Enhancements (GLEs) and the measurements of anisotropic galactic cosmic ray flux near Earth which reflect disturbances in the interplanetary magnetic field. The measurement of a GLE by the worldwide network of NMs represents an alert for later arriving low-energy solar particles with higher intensities. These low-energy particles may be a radiation hazard to humans in airplanes and to astronauts in space. The observation of anisotropic galactic cosmic ray flux can forecast an approaching interplanetary coronal mass ejection which may lead to disastrous geomagnetic disturbances. In the presentation the current situation of the use of NM data in space weather applications will be shown and it will be tried to present future extensions and improvements.
11:15	Studying the SEP-GLE coupling through Neutron Monitor data modeling (invited)	Plainaki, C et al.	Invited Oral
	C. Plainaki[1,2], M. Laurenza[1], H. Mavromichalaki[2], M. Storini[1]
	[1]INAF-IAPS, Via del Fosso del Cavaliere, 00133, Rome, Italy; [2]Nuclear and Particle Physics Section, Physics Dpt., National and Kapodistrian University of Athens, Greece
	GLE events are related to the most energetic class of solar energetic particle (SEP) events, associated with both solar flares and coronal mass ejections (e.g. [1]), and requiring acceleration processes that produce particles with energies ≥500 MeV upon entry in the Earth’s atmosphere. GLE data recorded by the worldwide neutron monitor network are a useful resource for space weather modeling during solar extreme events. Among the numerous space weather models available to the community, the NMBANGLE PPOLA [2] is a modified version of the original NMBANGLE model [3], based on Dorman's coupling coefficient method [4], aiming at the calculation of the SEP properties during GLEs through the exclusive use of ground-based Neutron Monitor data from the worldwide network. Technically, the model treats this network as an integrated omnidirectional spectrometer and solves the inverse problem of the SEP-GLE coupling. In particular, the NMBANGLE PPOLA model dynamically calculates the SEP spectrum and flux spatial distribution at some altitude in the atmosphere, assuming a power-law in rigidity primary spectrum with two free parameters (spectral index and amplitude) and a narrow-beam angular distribution for the SEP flux direction [2]. In this paper, we present a short overview of the application of the NMBANGLE PPOLA model to different GLEs, discussing the derived characteristics of the relativistic SEP fluxes. We also discuss some improvements of the current model in the context of Space Weather efficient monitoring through Neutron Monitors. [1] Laurenza M. et al. 2009 Space Weather 7 S04008 doi:10.1029/2007SW000379 [2] Plainaki C, et al. 2010 Solar Phys. 264 239 [3] Plainaki C, et al. 2007 J. Geophys. Res. A 112 4102 [4] Dorman LI 2004 Astrophys. Space Sci. Libr. 303
11:30	NMDB: current status and perspectives	Steigies, C et al.	Invited Oral
	Christian T. Steigies
	IEAP, CAU Kiel, Germany
	The Neutron Monitor DataBase (NMDB) was started with funding from the European Comission as an FP7 project in 2008 and 2009. Since the funding for the project has ended, many more data providers from around the world have joined NMDB to make their data available in real-time for free for scientific and educational purposes. In addition some data from the World Data Center for Cosmic rays from stations that have closed long ago is being offered also via NMDB, so that NMDB is getting closer to its goal to provide easy access to all Neutron Monitor measurements. Data offered via NMDB is still owned by the stations that provide their data to NMDB. Since NMDB data is used by more and more services and applications, we as the data providers and as NMDB have to make sure that our property rights are respected and that our work is properly acknowledged to be able to offer our data also in the future. NMDB is continuing without funding, many data providers continue to operate their Neutron Monitors without adequate funding, but without propper acknowledgements it will become impossible for data providers to apply for grants at their funding agencies. The NMDB is not a static database, the data volume and traffic is constantly increasing, but also the database technology has made great progress since NMDB was started nearly 10 years. To keep up with the latest technology, NMDB has to migrate to newer versions of the SQL and server software. This may cause some changes to the interface to NMDB but it will assure that NMDB can keep up with increased data and data usage in the coming years. The new setup of the NMDB infrastructure will be presented.
11:40	Vector anisotropy of the cosmic rays in the beginning of the Forbush decreases for space weather forecasting	Abunina, M et al.	Invited Oral
	Maria Abunina, Anatoliy Belov, Artem Abunin, Evgeniya Eroshenko, Victoria Oleneva, Victor Yanke
	Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN)
	The behavior of cosmic ray density and the anisotropy in the first hours of Forbush decrease is studied during the period 1957-2014. Only Forbush effects followed by the arrival of the interplanetary shock wave were considered. It is shown that already in the beginning of events the magnitude of the first spherical harmonic of anisotropy increases substantially, and its direction changes significantly. The more powerful interplanetary disturbance the more changes are manifested in anisotropy. By the changes of some parameters of the cosmic ray density and anisotropy one can have the information about the heliolongitude of the source of disturbance, and on the further development of the Forbush decrease and geomagnetic activity as well.
11:50	The not so standard Neutron Monitor: An initiative for standardization and the PHENOMENON Package	Sarlanis, C et al.	Oral
	Christian Steigies, Christos Sarlanis
	Christian-Albrechts-Universität Kiel (CAU), ISNet Co
	Neutron monitors (NMs) continuously record the cosmic-ray (CR) primary intensity for more than 50 years. Since the International Geophysical Year (IGY) 1957, the IGY NM quickly became recognized as an efficient detector for the study of CRs with a world data center (WDC) for CRs, which provides one hour averages of CR intensities, being established that same year. The successor of IGY was the super NM64 which is used until today. In the 1990's NMs followed the revolution of the new technology and started publishing real-time data via the internet. In recent times, an initial effort to bring together as many NMs as possible and store their data into a database (i.e. NMDB; http://nmdb.eu) has grown into a global one, providing 1-minute data in a standard format. The processing of the NM data is often necessary in order to achieve high quality and to implement real time tools. This is not a trivial task, and different NMs apply different procedures. Hence, in this work we present the first step of a larger effort to implement a package of correcting algorithms in open source Python scripts, distributed freely to the NM community via NMDB, aiming to open the discussion on the standardization of the processes for the corrections of NM data and to provide all parts of such a standard data processing procedure. The package as a whole, is entitled PHENOMENON (PytHon corrEctioN algOrithMs for nEutroN mONitors). In what follows, we describe and inter-compare three basic algorithms used in NMs: (i) the Simple Sum algorithm; (ii) the Median Editor algorithm; (iii) the Median plus σ algorithm, providing, example implementations of all algorithms, as well as, tests with different input data.

Posters

Friday November 18, 10:00 - 11:00, Poster Area

1	Present status and modernisation of the Dourbes Cosmic Ray Observatory for improved space weather research and forecasting	Sapundjiev, D et al.	Invited p-Poster
	Danislav Sapundjiev[1,2], Stanimir M. Stankov[1,2]
	[1]Solar-Terrestrial Centre of Excellence (STCE); [2]Royal Meteorological Institute of Belgium
	The NM64 neutron monitor, like the one in operation at the RMI Geophysical Centre in Dourbes (50.1°N, 4.6°E), has proved to be an important measurement tool for space weather research and development of forecasting and prediction services. However, modern research poses higher, more challenging demands on the quality of measurements – higher accuracy and precision, better resolution, and real-time dissemination of data and products. Such demands become even more challenging when utilising an instrument that has been conceived and built more than half a century ago. Currently, the neutron monitor in Dourbes consists of 9 detector tubes and aging electronics and computer peripherals. In order to comply with the abovementioned modern-age requirements, in addition to the permanent maintenance, the Dourbes neutron monitor needs substantial refurbishment and upgrades. Recently, several modules of the electronics have been replaced, including the data logging system, the power supply units and cable infrastructure. In addition to the hardware upgrades, computer software has been developed in-house to improve data acquisition, processing, and archiving, including data quality assessment and cleaning in real time. The construction of a second neutron monitor, equivalent to the one currently in use, is in progress. The planned addition of 9 new detector tubes marks a significant upgrade towards the building a modern and more reliable cosmic ray observatory of international standard. The second monitor is being built in several stages. In the first stage, a section of 3 detector tubes will be constructed and tested in the coming months. Initially, we will exploit the producer-free concept, i.e. without the producer, made out of lead (Pb) and used for neutron multiplication. This will allow the verification of several theoretical and computer simulations, performed by a nuclear transport code, in order to investigate the neutron monitor’s yield functions. In the following stages, the second neutron monitor will be completed with additional 2 sections of 3 tubes – in one or two steps. The addition of a lead producer will be decided after data comparison and differentiation between both monitors during calm and storm periods. An additional expansion of the Dourbes observatory is envisaged with the construction of a muon telescope. The project is still at early design stage. The first version of the design is expected soon together with a budget estimate.
2	A Mini Neutron Monitor in Central Antarctica (Dome Concordia)	Poluianov, S et al.	Invited p-Poster
	Stepan Poluianov[1], Ilya Usoskin[1,2], Harm Moraal (deceased)[3], Helena Krueger[3], Giampietro Casasanta[4], Rita Traversi[5], Roberto Udisti[5]
	[1]Sodankylä Geophysical Observatory, University of Oulu, Finland; [2]ReSoLVE, University of Oulu, Finland; [3]North-West University, Potchefstroom, South Africa; [4]Institute of Atmospheric Sciences and Climate, CNR, Rome, Italy; [5]Department of Chemistry "Ugo Schiff", University of Florence, Italy
	A new detector of cosmic rays is installed at station Concordia in Central Antarctica (75.10S, 123.38E, 3233 meters a.s.l.). It is built by the North-West University (Potchefstroom, South Africa) for the University of Oulu in the framework of the Finnish Antarctic Research Program (FINNARP). The setup consists of two modules: a standard-design mini neutron monitor and a lead-free, so-called "bare", neutron monitor. They got the names DOMC and DOMB, respectively. Station Concordia is an optimal site to detect solar cosmic rays and low-energy cosmic rays because of low geomagnetic cut-off and high altitude. The site has the asymptotic acceptance cone, which is almost perpendicular to the equatorial plane pointing to geographical southern latitudes > 80 degrees for particles with energies above a few GeV. Thus, it is the only station, which accepts cosmic rays from the south polar direction. The instrument has started its operation in January 2015 and works properly since then. The average count rates of DOMC and DOMB are about 960 and 260 counts/min, respectively. The preliminary barometric correction coefficients are -0.75+-0.07 %/mbar and -0.71+-0.04 %/mbar with the reference atmospheric pressure set to 650 mbar. The data are received on a daily basis and will be publicly available in the databases cosmicrays.oulu.fi and nmdb.eu.
3	Application of neutron monitor data for space weather	Mishev, A et al.	e-Poster
	Alexander Mishev[1], Ilya Usoskin[1,2]
	[1]Space Climate research group, University of Oulu, Finland; [2]Sodankyla Geophysical Observatory (Oulu unit), University of Oulu, Finland
	One of the most important topics of space weather is a precise assessment of the effect of solar energetic particles (SEPs) on the air crew radiation dose exposure, specifically during eruptive events on the Sun, as well as their influence on some atmospheric processes. For this purpose a detailed information about SEP specra and anisotropy is necessary since the flux of SEP can be essentially anysotropic. This information is necessary to be obtained in the course of the events. This task can be achieved using neutron monitor (NM) data. In general, the analysis of SEP spectral and angular characteristics using NM data (for special class of events, called ground level enhancements GLEs) requires realistic modeling of propagation of those particles in the Earth's magnetosphere and atmosphere. Here, using method consisting of consecutive steps, namely a detailed computation of the NM assymptotic cones and rigidity cut-offs, initial guess and application of a NM response modeling using a NM yield function, we derivde the rigidity spectra and anisotropy characteristics of several major GLEs by a convenient optimization procedure. We evaluated the SEP spectra and pitch angle distributions in their dynamical development throughout several GLEs. Subsequently, on the basis of the derived spectra and angular characteristics and the previously computed yield functions, we calculated the ion production rate and effective dose during the GLEs. Several examples are shown.
4	Application of NM derived spectra for computation of ionization effect during major GLE events of solar cycle 23	Mishev, A et al.	e-Poster
	Alexander Mishev[1], Peter Velinov[2]
	[1]Space Climate research group, University of Oulu, Finland; [2]Institute for Space Research and Technology, Bulgarian Academy of Sciences
	According to the present knowledge the galactic cosmic rays (GCRs) are the main source of ionization in the Earth’s stratosphere and troposphere. The induced by CR particles ionization play an important role in various processes related to atmospheric physics and chemistry. Occasionally solar energetic particles enhance the ion production, specifically over polar caps during major energetic solar processes, namely during ground level enhancements (GLEs). During the solar cycle 23, sixteen GLE events were observed with intensities ranging ∼ 3 – 277%. The first event occurred on 6 November 1997 (GLE 55) and the last event occurred on 13 December 2006 (GLE 70). In the paper presented here we demonstrate the application of neutron monitor (NM) derived solar energetic particle (SEP) spectra for estimate the short, medium and long term ionization effect in the atmosphere during and after GLEs. We focus on several GLEs, namely GLE 59 (Bastille day event on 14 July 2000), which was the first major event positioned exactly at the maximum of solar cycle 23 and GLE 70, which was the last one. We briefly discuss the ionization effect during Halloween 2003 sequence of GLEs 65-67 and the major event GLE 69 of 20 January 2005. For the computations we apply a full Monte Carlo 3-D model for cosmic ray induced ionization, allowing us to compute the ion production. The ion production rate during the events is considered as a superposition of realistically considered galactic cosmic ray flux taking into account the accompanying Forbush decrease and solar energetic particles. The ion production rate and ionization effect are computed as a function of the altitude above the sea level at several rigidity cut-offs, namely 1 GV, 2 GV and 3 GV. The ionization effect relative to the average due to GCRs is computed at several time scales. In the work are given some applications of GCR ionization effects influence to explaining the processes and mechanisms of the space weather and mechanisms in solar-terrestrial physics.
5	A study on precursors of Forbush decreases and their common features	Lingri, D et al.	p-Poster
	Dimitra Lingri[1], Maria Papailiou[1], Helen Mavromichalaki[1], Anatoly Belov[2], Eugenia Eroshenko[2], Maria Abunina[2], Artem Abunin[2]
	[1]Faculty of Physics, National and Kapodistrian University of Athens, Athens, Greece; [2]Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation (IZMIRAN) of the Russian Academy of Sciences, Moscow, Russia
	As suggested in many studies the pre-increases or pre-decreases of the cosmic ray intensity (known as precursors), which usually precede a Forbush decrease, could serve as a useful tool for studying space weather effects. The asymptotic longitudinal cosmic ray distribution diagrams were used to plot specified Forbush decreases, by using the “ring of stations” method. Apart from hourly cosmic ray intensity data, provided by the worldwide network of neutron monitor stations, data on solar flares, solar wind speed, geomagnetic indices (Kp and Dst), and interplanetary magnetic field will be used for the analysis of the examined cosmic ray intensity decreases. From these diagrams and the known parameters of the Forbush decreases obtained from the IZMIRAN database, the common features of the examined events will be identified.