TY - JOUR
T1 - Thermal structure of the martian upper atmosphere from MAVEN NGIMS
AU - Stone, Shane W.
AU - Yelle, Roger V.
AU - Benna, Mehdi
AU - Elrod, Meredith K.
AU - Mahaffy, Paul R.
N1 - Funding Information: This work was supported by funding from the MAVEN mission, a part of the NASA Mars Exploration Program. The MAVEN data sets are publicly available on the NASA Planetary Data System (PDS, https://pds.nasa.gov) and the MAVEN Science Data Center (SDC, https://lasp.colorado.edu/maven/ sdc/public/). Data used in this manuscript, including calculated densities, derived temperatures, and 1-D model output, can be obtained from https://doi.org/10.5281/ zenodo.1215867. Funding Information: This work was supported by funding from the MAVEN mission, a part of the NASA Mars Exploration Program. The MAVEN data sets are publicly available on the NASA Planetary Data System (PDS, https://pds.nasa.gov) and the MAVEN Science Data Center (SDC, https://lasp.colorado.edu/maven/ sdc/public/). Data used in this manuscript, including calculated densities, derived temperatures, and 1-D model output, can be obtained from https://doi.org/10.5281/zenodo.1215867. Publisher Copyright: ©2018. American Geophysical Union. All Rights Reserved.
PY - 2018
Y1 - 2018
N2 - The Neutral Gas and Ion Mass Spectrometer (NGIMS) aboard the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures the structure and variability of the Martian upper atmosphere. We use NGIMS density profiles to derive upper atmospheric temperature profiles and investigate the thermal structure of this region. The thermal structure of the upper atmosphere is a critical component of understanding atmospheric loss to space, the main science objective of MAVEN, and measured temperatures serve as inputs to and constraints on photochemical and global circulation models. We describe proper treatment of the NGIMS data and correct for the horizontal motion of the spacecraft. Temperature profiles from week-long, low-altitude excursions executed by MAVEN, called Deep Dips, are used to investigate the diurnal variation of the temperature and the thermospheric gradient, which varies between 1.33 ± 0.16 and 2.69 ± 0.33 K km −1 on the dayside. NGIMS measurements acquired on nominal MAVEN orbits over more than a Martian year further elucidate the diurnal and latitudinal variations of the temperature. Diurnal variations of about a factor of 2, from 127 ± 8 to 260 ± 7 K, are observed high in the exosphere, and latitudinal variations of 39 ± 17 K are observed in this region. Comparisons indicate broad agreement between temperatures derived from MAVEN NGIMS with previous in situ and remote sensing observations of upper atmospheric temperatures. NGIMS temperatures are also shown to be consistent with predictions of a 1-D model which includes solar UV and near IR heating, thermal conduction, and radiative cooling in the CO 2 v 2 15-μm band.
AB - The Neutral Gas and Ion Mass Spectrometer (NGIMS) aboard the NASA Mars Atmosphere and Volatile EvolutioN (MAVEN) mission measures the structure and variability of the Martian upper atmosphere. We use NGIMS density profiles to derive upper atmospheric temperature profiles and investigate the thermal structure of this region. The thermal structure of the upper atmosphere is a critical component of understanding atmospheric loss to space, the main science objective of MAVEN, and measured temperatures serve as inputs to and constraints on photochemical and global circulation models. We describe proper treatment of the NGIMS data and correct for the horizontal motion of the spacecraft. Temperature profiles from week-long, low-altitude excursions executed by MAVEN, called Deep Dips, are used to investigate the diurnal variation of the temperature and the thermospheric gradient, which varies between 1.33 ± 0.16 and 2.69 ± 0.33 K km −1 on the dayside. NGIMS measurements acquired on nominal MAVEN orbits over more than a Martian year further elucidate the diurnal and latitudinal variations of the temperature. Diurnal variations of about a factor of 2, from 127 ± 8 to 260 ± 7 K, are observed high in the exosphere, and latitudinal variations of 39 ± 17 K are observed in this region. Comparisons indicate broad agreement between temperatures derived from MAVEN NGIMS with previous in situ and remote sensing observations of upper atmospheric temperatures. NGIMS temperatures are also shown to be consistent with predictions of a 1-D model which includes solar UV and near IR heating, thermal conduction, and radiative cooling in the CO 2 v 2 15-μm band.
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U2 - 10.1029/2018JE005559
DO - 10.1029/2018JE005559
M3 - Article
SN - 2169-9097
VL - 123
SP - 2842
EP - 2867
JO - Journal of Geophysical Research: Planets
JF - Journal of Geophysical Research: Planets
IS - 11
ER -