The new Athens center on data processing from the neutron monitor network in real time

International audienceThe ground-based neutron monitors (NMs) record galactic and solar relativistic cosmic rays which can play a useful key role in space weather forecasting, as a result of their interaction with interplanetary disturbances. The Earth's-based neutron monitor network has been used in order to produce a real-time prediction of space weather phenomena. Therefore, the Athens Neutron Monitor Data Processing Center (ANMODAP) takes advantage of this unique multi-directional device to solve problems concerning the diagnosis and forecasting of space weather. At this moment there has been a multi-sided use of neutron monitors. On the one hand, a preliminary alert for ground level enhancements (GLEs) may be provided due to relativistic solar particles and can be registered around 20 to 30 min before the arrival of the main part of lower energy particles responsible for radiation hazard. To make a more reliable prognosis of these events, real time data from channels of lower energy particles and X-ray intensity from the GOES satellite are involved in the analysis. The other possibility is to search in real time for predictors of geomagnetic storms when they occur simultaneously with Forbush effects, using hourly, on-line accessible neutron monitor data from the worldwide network and applying a special method of processing. This chance of prognosis is only being elaborated and considered here as one of the possible uses of the Neutron Monitor Network for forecasting the arrival of interplanetary disturbance to the Earth. The achievements, the processes and the future results, are discussed in this work

Applications and usage of the real-time Neutron Monitor Database

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Primary Data Processing Algorithms for Neutron Monitors

The primary data processing of the neutron monitors is a necessary procedure in order to provide the worldwide network of neutron monitors with high quality data. The procedure should be performed in a real time code which means that it should be fast and make use only of the past measurements of a neutron monitor. In general, the data correction algorithms are based on the comparison among the different channels of the detectors. Such methods, which are used currently by the Athens neutron monitor station as well as by many other stations are the Median Editor and the Super Editor. In this work, two new algorithms that are currently being developed in the Athens Station are presented. The first one is based on an Artificial Neural Network model, while the second one is based on a pure statistical model

Artificial Neural Network Approach of Cosmic Ray Primary Data Processing

One of the most critical points in the detection of cosmic rays by neutron monitors is the correction of the raw data. The data that a detector measures may be distorted by a variety of reasons and the subtraction of these distortions is a prerequisite for processing them further. The final aim of these corrections is to keep only the fluctuations related to the real cosmic-ray intensity. To achieve this, we analyze data from identical neutron monitor detectors which provide a configuration with the ability to exclude the distortions by comparing the counting rate of each detector. Based on this method, a number of effective algorithms have been developed: Median Editor, Median Editor Plus, and Super Editor are some of the algorithms that are being used in the neutron monitor data processing with satisfactory results. In this work, a new approach for the correction of the neutron monitor primary data with a completely different method, based on the use of artificial neural networks, is proposed. A comparison of this method with the algorithms mentioned previously is also presented. © 2012 Springer Science+Business Media Dordrecht

Primary Malignant Melanoma of Renal Pelvis with Extensive Clear Cell Change.

Our presentation illustrates a rare case of primary renal pelvis malignant melanoma in a 35-year-old man. The diagnosis of malignant melanoma was based on immunophenotype and the detection of intracellular melanin pigment. The renal origin was proven by the presence of scattered melanocytes within the urothelium of the pelvis. The tumor exhibited extensive clear cell change that closely mimics clear cell renal cell carcinoma. The patient's clinical history did not disclose any signs of previous melanocytic skin or mucosa lesions. Differential diagnosis includes tumors capable of synthesizing melanin or expressing melanocytic markers

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

Real-time GLE alert in the ANMODAP Center for December 13, 2006

Within the last years, a real-time system to monitor high energy cosmic rays for space weather use has been operated at Athens cosmic ray station. Neutron monitors and satellite high resolution data in real time are used, making it possible to observe cosmic rays in dual energy range observations. In large solar energetic particle (SEP) events, ground level enhancement (GLE) can provide the earliest alert for the onset of the SEP event. This system watches for count rate increases recorded in real time by 23 neutron monitors, which triggers an alarm if a ground level enhancement (GLE) of cosmic ray intensity is detected. Our effort is to determine optimal strategies for detecting the GLE event at a very early stage, while still keeping the false alarm rate at a very low level. We have studied past events to optimize appropriate intensity threshold values and a baseline to determine the intensity increase. We define three levels of alarm (watch, warning and alert) on the basis of the number of stations that record a significant intensity increase. For every station there is a program which every minute calculates in real time the mean value of the last sixty minutely measurements and compares this value with a threshold. If we have five pre-alert points in succession, we define a Station Alert. If we see at least three stations in station alert mode, another program provides a General GLE Alert. A statistical analysis on the last ten GLEs recorded from 2001 till 2006 using 1-min data from our database, produced GLE alarms for nine events in our system. Alarm times for these nine events are compared with satellite data separating if the event is GLE or magnetospheric one. The GLE alert precedes the earliest alert from GOES (100 MeV or 10 MeV protons) by 4-33 min. When the alert is final then an automated e-mail is sent to all the interested users. An alert signal was established at December 13, 2006 by the ANMODAP Center and for first time an automated e-mail alarm signal was sent out by our system determining the onset of the GLE70 event. A detailed analysis of this alert is discussed. © 2008 COSPAR

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 Earth’s 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