John W. BieberJohn ClemPaul EvensonRoger PyleDavid RuffoloAlejandro SáizManeenate WechakamaBartol Research InstituteMahidol UniversityKasetsart University2018-08-242018-08-242007-01-01Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007. Vol.1, No.SH (2007), 229-2312-s2.0-63949086403https://repository.li.mahidol.ac.th/handle/20.500.14594/25134Ground Level Enhancements are more likely to occur when the Sun is very active. The most recent GLE was a maverick. It occurred near solar minimum, but it was a large event by historical standards, with a peak increase exceeding 70% at some stations. This paper reports initial observations of the GLE of December 13, 2006 based on data returned by the Spaceship Earth neutron monitor network.Mahidol UniversityPhysics and AstronomyConference PaperSCOPUS