Time Variations of Mars Gravity Field From Mars Global Surveyor and Odyssey Data

All MGS and Odyssey tracking data till mid-2006 have been reprocessed for monitoring the Mars gravity field time variations which are due to seasonal mass transfers between the planet surface and its atmosphere. Time series of the zonal lumped harmonics of degrees two and three at ten day interval have been determined, which exhibit and confirm the annual and semi-annual variations previously found by other groups and the authors. The new solution is more stable than the one found in 2005 by the authors, mostly due to the addition of Odyssey data and also the longer data span. The solution parameter set includes the k2 Love number, which value (0.11) looks also more reliable.