Science goals and objectives. Almost a decade after the end of the mars global surveyor (MGS) mission the data collected by the thermal emission spectrometer (TES) onboard MGS still constitute an…

This is a $387,011 grant awarded by NASA to the Space Science Institute (SSI), a nonprofit research organization based in Boulder, Colorado. The grant is for the re-calibration and expansion of the data collected by the Thermal Emission Spectrometer (TES) instrument on the Mars Global Surveyor (MGS) mission. The goal is to re-process the TES data to improve the accuracy of retrievals for atmospheric aerosols, water vapor, and surface mineralogy. The new data products will be archived in the NASA Planetary Data System (PDS) to augment the existing TES datasets. This work is relevant to the Planetary Data Archiving, Restoration, and Tools (PDART) program, which supports the restoration and archiving of planetary science data. The grant does not have a set-aside designation, as SSI competes for awards based on scientific and technical merit. SSI has extensive experience supporting NASA, NSF, and DOE through both prime and subcontract research awards in areas such as astrophysics, planetary science, and atmospheric science.

Science goals and objectives. Almost a decade after the end of the mars global surveyor (MGS) mission the data collected by the thermal emission spectrometer (TES) onboard MGS still constitute an invaluable source for analysis of the martian atmosphere and surface. TES provided first multi-year global view of the martian dust and water vapor cycles, atmospheric and surface temperatures, and provided a window into surface mineralogy. The data collected by TES are widely used in the mars community. The goal of the proposed study is to RE-calibrate infrared spectra collected by the TES spectrometer using a more accurate calibration function. The RE-calibrated spectra will be used to RE-retrieve opacities of the atmospheric aerosols (dust and water ICE clouds), the column abundances of the water vapor and to extend retrievals of surface mineral abundances. In addition, the TES atmospheric data products (dust and ICE cloud opacities, water vapor abundances retrieved from daytime nadir observations) currently archived in the NASA planetary data system (PDS) will be supplemented with the data products retrieved from the nighttime and limb observations, and from observation over cold surfaces. The expanded dataset of the atmospheric data products (aerosols opacities and water vapor column abundances) will be archived in the PDS. Methodology. The TES spectra will be RE-calibrated using new estimates of the calibration function. The PI recently completed a NASA-funded study to RE-calculate the TES calibration functions utilizing long-term averages over hundreds of MGS orbits. These improved calibration functions more accurately reflect the dependence on the instrument temperature and exhibit reduced levels of the instrumental noise and of the systematic radiometric error. Improved understanding of the nature of the radiometric error affecting TES data collected after orbit 7000 enables error correction in the nadir and limb spectra. This error correction will improve quality of the derived data products (atmospheric opacities retrieved from limb spectra and from spectra collected over cold surfaces) and will enable increasing surface coverage of the surface mineralogy retrievals. The TES atmospheric data products currently archived in the NASA PDS are limited to daytime nadir retrievals over warm surfaces (tsurf>220 k). These data products will be RE-derived with the newly recalibrated and corrected for radiometric error TES spectra. In addition, limb spectra and spectra collected over cold surface will be used to retrieve opacities of the atmospheric dust and water ICE, and mixing ratios and column abundances of the water vapor, and in this way to augment the current TES PDS dataset. Retrievals of surface mineralogy will be extended beyond the orbit 7000 and used to improve spatial coverage of the TES mineral maps. Relevance to pdart. The proposal is relevant to the pdart program since IT will RE-calibrate MGS TES spectrometer data and will generate new data products. RE-calibration falls under data set restoration and archiving activities within the scope of pdart. The new data products will include the RE-calibrated (corrected) TES spectra, atmospheric data products (dust and water ICE cloud opacities, water vapor column abundances) derived from these RE-calibrated spectra. Additional TES data products will include nighttime and limb dust and ICE cloud opacities, water vapor column abundances over cold surfaces.