Forbush Decreases on the Martian Surface during the 2014 Mars Oppositio

Monday, 15 December 2014
Bernd Heber1, Arik Posner2, R F Wimmer-Schweingruber1, Henning Lohf1, Jingnan Guo1, Cary J Zeitlin3, Javier Martín-Torres4, Maria-Paz Zorzano4, Christian T Steigies5, Yihua Zheng6, Lars Berger1, Nina Dresing1, Christian Drews1, Konstantin Herbst7, Patrick Kühl1, Peter J MacNeice8, Dusan Odstrcil9, Lutz Rastaetter8, Rudolf Beaujean5, Sönke Burmeister10, Francis Cucinotta11, Bent Ehresmann12, Don Hassler13, Jan Kohler1, Cesar Martin-Garcia1, Reinhold Müller-Mellin5, Scot CR Rafkin12, Myung-Hee Y Kim14 and Mark Bullock12, (1)University of Kiel, Kiel, Germany, (2)NASA Headquarters, Washington, DC, United States, (3)Southwest Research Institute, Oakland, CA, United States, (4)Centro de Astrobiologia, Madrid, Spain, (5)Christian-Albrechts-Universität zu Kiel, Kiel, Germany, (6)NASA/GSFC, Greenbelt, MD, United States, (7)Organization Not Listed, Washington, DC, United States, (8)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (9)George Mason University Fairfax, Fairfax, VA, United States, (10)Christian-Albrechts-Universität zu Kiel, Institute for Experimental and Applied Physics, Extraterrestrial Physics, Kiel, Germany, (11)University of Nevada Las Vegas, Las Vegas, NV, United States, (12)Southwest Research Institute Boulder, Boulder, CO, United States, (13)Southwest Research Inst, Boulder, CO, United States, (14)Wyle Information Systems, Inc., Lanham, MD, United States
We analyze Forbush decreases that were observed both on the surface of the Earth and Mars during and around the time period of the Mars opposition in April 2014. More than 100 Forbush decreases were observed over one complete Martian year (the equivalent of 1.88 Earth years) since the landing of the Mars Science Laboratory in 2012. We find that several Forbush decreases occurred that can be linked to the same interplanetary structures affecting both planets. Observations of the Radiation Assessment Detector (RAD) and the Rover Environmental Monitoring Station (REMS), the neutron monitor network on Earth and of several other space missions are used for our analysis. We compare commonly observed Forbush decreases with respect to frequency, magnitude, and duration under the given solar cycle conditions and identify individual drivers of the Forbush decreases on Mars, i.e. recurrent and transient solar wind structures in the inner heliosphere.