CRISM multispectral summary products: Parameterizing mineral diversity on Mars from reflectance

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) is the most recent spectrometer to arrive at Mars. The instrument is a hyperspectral imager covering visible to near‐infrared wavelengths (0.37–3.92 μ m at 6.55 nm/channel). Summary products based on multispectral parameters will be derived from reflectances in key wavelengths for every CRISM observation. There are 44 summary products formulated to capture spectral features related to both surface mineralogy and atmospheric gases and aerosols. The intent is to use the CRISM summary products as an analysis tool to characterize composition as well as a targeting tool to identify areas of mineralogic interest to observe at higher spectral and spatial resolution. This paper presents the basis for the summary products and examines the validity of the above approach using data from the Mars Express OMEGA instrument, a visible/near‐infrared imaging spectrometer with spatial and spectral coverage similar to that of CRISM. Our study shows that the summary products vary in utility, but succeed in capturing the known diversity of the Martian surface and variability of the Martian atmosphere, and successfully highlight locations with strong spectral signatures. Thus the CRISM summary products will be useful in both operations and science applications. Caveats and limitations related to the summary products and their interpretation are presented to assist with their application by the community at large.