The vertical transport of methane from different potential emission types on Mars

Abstract

AbstractThe contrasting evolutionary behavior of the vertical profile of methane from three potential release scenarios is analyzed using a global circulation model with assimilated temperature profiles. Understanding the evolving methane distribution is essential for interpretation of future retrievals of the methane vertical profile taken by instruments on the ExoMars Trace Gas Orbiter spacecraft. We show that at methane release rates constrained by previous observations and modeling studies, discriminating whether the methane source is a sustained or instantaneous surface emission requires at least 10 sols of tracking the emission. A methane source must also be observed within 5 to 10 sols of the initial emission to distinguish whether the emission occurs directly at the surface or within the atmosphere via destabilization of metastable clathrates. Assimilation of thermal data is shown to be critical for the most accurate backtracking of an observed methane plume to its origin.