Revisiting the identification of methane on Mars using TES data

The presence and variability of methane in the Martian atmosphere has been investigated by several authors and spurred a lively discussion. In this context, we address our previous inference of spatial and temporal CH₄ variability identified from Mars Global Surveyor Thermal Emission Spectrometer measurements which was used to suggest the possible existence of a martian methane cycle. The importance of the topic requires a clear assessment of such variability to correctly comprehend the possible production and destruction mechanisms of Martian methane. It is therefore important to carefully revisit previous results from a different perspective to confirm them before they are used for further investigations. We here describe in detail a new procedure used to validate these earlier Thermal Emission Spectrometer measurements and thoroughly analyze the results obtained with the revised procedure. In spite of our efforts of defining an efficient data analysis procedure, we have not been able to either confirm or refute the existence of the spatial and temporal variability of methane. Nevertheless, our work has produced new interesting tools, which, with the necessary adaptation, can be of some aid in processing and interpreting planetary spectra and, in general, for all the other cases requiring a preliminary selection of data included in very extensive datasets, which are difficult to be efficiently treated with traditional techniques.