On possible revision of the defjnition of GLE and a new class of - - PowerPoint PPT Presentation
Busan, South Korea 12-20 July 2017 On possible revision of the defjnition of GLE and a new class of "sub-GLE" events S. Poluianov 1,2 , A. Mishev 2 , I. Usoskin 1,2 , D. Smart 3 , M. Shea 3 1-Sodankyl Gephysical Observatory,
1-Sodankylä Gephysical Observatory, University of Oulu, Finland 2-Space Climate Research Unit, University of Oulu, Finland 3-SSSRC, Nashua, NH, USA
53 neutron monitor stations
A high-elevation polar site has:
Very favorable for detection of SEP . There are only two such sites at the Earth:
Unfortunately, there is no high- elevation CR station in Geenland, but there are two such stations in Antarctica:
since 1964),
since 2015). Both setups have “standard” and “bare” (lead-free) NMs.
Enhancement (of the NM count rate over the GCR background) is an event sporadically caused by solar energetic particles (SEP).
been registered since 1942. (gle.oulu.fj) GLE #67 on 02 Nov 2003
A GLE event is registred when there are simultaneous statistically signifjcant enhancements of the count rates of at least two difgerently located NMs and a corresponding enhancement in the proton fmux measured by a space-borne instrument(s). The defjnition is very important for SEP studies, and crucial for ones based
It has been formulated approximately as this:
(gle.oulu.fj) This event formally matches the defjnition of GLE.
More details in the talk given by A. Mishev [SH024]
GLE71 (17 May 2012, approx. plot) subGLE (29 Oct 2015) GCR for 2015
A GLE event is registred when there are simultaneous statistically signifjcant enhancements of the count rates of at least two difgerently located NMs including at least one NM near the sea level and a corresponding enhancement in the proton fmux measured by a space- borne instrument(s). “Near the sea level” means not higher than one interaction length of the nucleonic component of the CR cascade above the sea level (approx. 900 g/cm2 or 1000 m). The proposal does not afgect the present list of GLEs, because all 71 “offjcial” events have been registered by at least one of near sea level NMs.
A sub-GLE event is registred when there are simultaneous statistically signifjcant enhancements of the count rates of at least two difgerently located high-elevation NMs and a corresponding enhancement in the proton fmux measured by a space-borne instrument(s), but no statistically signifjcant enhancement in the count rates of NMs near the sea level. On the term: it is already in use (e.g., Atwell et al., ICES2015), although is not clearly defjned.
GLE – registered by at least two NMs in different locations
GLE – registered by at least two differently located NMs including at least one near the sea level subGLE – registered by at least two differently located high- elevation NMs, but not by sea-level NMs. THE PRESENT DEFINITION (from the 1970s) THE PROPOSING DEFINITIONS The proposal does not afgect the present list of GLEs, because all 71 “offjcial” events have been registered by at least one of near sea level NMs.