Long Term Change Detection on Mars using HRSC images in comparison to other multi-temporal image data sets

Kurzfassung

The 2-decade long observation time series of the High Resolution Stereo Camera (HRSC) onboard Mars Express provides the precious opportunity to search for long-term surface changes on Mars in comparison to other multi-temporal image data of even earlier missions, such as Viking, providing a time interval for possible change of at least 24 years. This study analyzed 231 HRSC images and compared them to other orbital image datasets including Viking, CTX, and MOC camera data. Via visual image inspection, a total of 532 changes were observed. 260 of those being wind streak orientation changes and 164 being possible albedo and dust cover changes. Other detected changes include wind streak shape modifications and newly appearing wind streaks or seemingly disappearing wind streaks. With additional data on global and local Martian dust storm events, as well as thermal inertia values from THEMIS, it was found that the observed wind streak shape and orientation changes are more likely caused by strong dust storm events, rather than by winds occurring on a day-today basis. Furthermore, an Iron Oxide Index was applied to HRSC images and shows potential relevance for future studies on the change of oxidation stages on the Martian surface, possibly even in the context of detecting changes using artificial intelligence.