Forbush Decreases on the Martian Surface during the 2014 Mars Oppositio

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.