A Study of the Martian South Polar Cap Using EMIRS and TES data
E.Altunaiji ,Mohammed Bin Rashid Space Centre, Dubai,UAE, , Dubai,UAE, M. D. Smith, NASA Goddard Space
Flight Center, Greenbelt, MD, USA, C. S. Edwards , Northern Arizona University, Department of Physics and
Astronomy, Flagstaff, AZ, USA, K.Badri ,Mohammed Bin Rashid Space Centre, Dubai,UAE, , Dubai,UAE

Introduction:
In July 2020, the Emirates Mars Mission (EMM)
launched to Mars and successfully entered the
planet’s orbit by February 9, 2021.The Mission aims
to gather information about the diurnal and seasonal
dynamics of the whole planet’s atmosphere (EMM,
Amiri et al., 2022). There are three instruments on
board EMM, which are the Emirates Mars Infrared
Spectrometer (EMIRS), the Emirates Exploration
Imager (EXI) and the Emirates Mars Ultraviolet
Spectrometer (EMUS). The first two instruments
capture information about the different constituents
found in the lower atmosphere such as water vapor,
ice clouds and dust among others to map out a threedimensional global thermal structure. The third
instrument (EMUS) is used to study the upper
atmosphere in order to have a meaningful picture
linking the lower atmosphere and the exosphere of
Mars.
One notable characteristic of Mars is that the planet
has polar ice caps comprised of carbon dioxide and
H2O ice, which show a rise during fall and winter
and a drop during the spring and summer.

Event (SPICE) Toolkit to determine the footprint
location on the surface.
Methodology:
One part of the analysis used for these data is the
ringing correction technique, which helps to smooth
and remove noisy data. Suppose the observed
radiance (including the ringing) is in a vector “R”,
then we can remove ringing using: Rnew(i) = [0.25 *
R(i-1) + 0.5 * R(i) + 0.25 * R(i+1)]. This
‘smoothing’ of the data in a mathematical method
also known as convolution.
In this study we use Q = [0.25, 0.5, 0.25 and Rnew =
conv (R, Q, ’same’). “Same” indicates matching the
Rnew vector with the length of the R vector.
Another analysis step used in the research is binning
using a moving boxcar average, which help identify
any trends in the data collected. The binning process
looks at results captured within an interval to be able
to calculate the average value and plot it. This
approach excludes the outliers, which is why
considering the median is more useful that looking at
the mean to minimize the outlier effect.

Research Objective:
This research aims to investigate the planet’s surface
temperature at the polar caps by utilizing data
captured by Thermal Emission Spectrometer (TES)
(TES, Christensen et al., 2001) and EMIRS
(Edwards et al. 2021 Space Science Reviews paper).
A rough indication of whether the polar caps are
covered with ice is the surface temperature, with
observations of 150 K or less. The study focused on
the South polar region as there is better coverage and
more data is available on it through available
observations.
Data and Tools:
One of the key instruments on the Mars Global
Surveyor (MGS) is the TES, which is made up of six
detectors that are aligned in a 2-by-3 formation.
While the nominal spot size of the TES detectors is
3x6 kilometers during mapping, it could have much
higher footprint because of the elliptical nature of its
orbit when aerobraking. The instrument also has two
channels: one is a broadband near-infrared bolometer
while the other is a hyperspectral thermal infrared
spectrometer. TES aerobraking spectra were taken
between Mars Year 23, Ls=180° and Mars Year 24,
Ls=30° and the geometry is calculated using
Spacecraft Planet Instrument Camera Matrix and

Figure1: Boxcar Technique
For the Mars pole’s surface temperature if the
emission angle is more than 70° then the spectrum
was skipped since spectra at such high emission
angles are only skimming the surface and can
include large atmospheric effects. The latitude is the
second factor, where the spectrum considered should
be located poleward of -50° as the coordinates of the
South Polar region considered here are within the
latitudes from -90° and -50°. Moreover, the surface

temperature was computed using the brightness
temperature between 300 cm-1 and 500 cm-1.

Results:
A series of polar-projection plots are made to see
how the south polar cap changes with season. Same
previous steps are applied to find surface
temperatures and to show if the pole is covered by
ice or not.

Figure2: Polar projections showing Surface
Temperature from TES observations

Figure3: Local Time-Latitude of Surface
Temperature from EMIRS observations

References:
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