The observations of Mars by the CRISM and OMEGA hyperspectral imaging
spectrometers require correction for photometric, atmospheric and thermal
effects prior to the interpretation of possible mineralogical features in the
spectra. Here, we report on a simple, yet non-trivial, adaptation to the
commonly-used volcano-scan correction technique for atmospheric CO_2, which
allows for the improved detection of minerals with intrinsic absorption bands
at wavelengths between 1.9-2.1 $\mu$m. This volcano-scan technique removes the
absorption bands of CO_2 by ensuring that the Lambert albedo is the same at two
wavelengths: 1.890 $\mu$m and 2.011 $\mu$m, with the first wavelength outside
the CO_2 gas bands and the second wavelength deep inside the CO_2 gas bands.
Our adaptation to the volcano-scan technique moves the first wavelength from
1.890 $\mu$m to be instead within the gas bands at 1.980 $\mu$m, and for CRISM
data, our adaptation shifts the second wavelength slightly, to 2.007 $\mu$m. We
also report on our efforts to account for a slight ~0.001 $\mu$m shift in
wavelengths due to thermal effects in the CRISM instrument.

本文介绍了一种改进的火山扫描技术，通过移动波长范围，实现了对 CO2 吸收带的消除，并提高了 CRISM 与 OMEGAHyperspectral 成像光谱计的探测矿物质量。