Maps of HCl and H2O abundances in the Martian atmosphere in MY36

This dataset is supplementary to related work published in JGR Planets (Faggi et al., 2025, DOI:10.1029/2025JE009105 )

The dataset stored here contains retrieved abundances of HCl [ppb] and H2O [ppm], as observed using the high-resolution echelle spectrograph, iSHELL, at the NASA IRTF observatory (Rayner et al., 2012, over three Martian seasons ( pre-Northern Summer Ls ~7 - 75 deg, pre-Southern Summer Ls~ 200 - 260 deg, and Southern Summer Ls ~ 274 - 319 deg).

The raw data are available at the NASA IRTF Archive (https://irtfweb.ifa.hawaii.edu/research/irtf_data_archive.php ), under the following Observing Program IDs: 2020B94, 2021A069, 2022A028, 2022B019.

The data-reduction scripts are available at https://github.com/nasapsg, and the retrieval software package used to create this dataset is Planetary Spectrum Generator (Villanueva et al., 2018, 2022), which is a free and publicly available online radiative trasfer and retrieval tool (https://psg.gsfc.nasa.gov).

This data was collected to investigate the HCl cycle and analyzing its spatial distributions to study its interplay with H2O. See realted published work for details on how to built a map (Faggi et al., 2025)

Each file contains the following information.

Each line provides the following values, divided by comma (,):

1) iset = Index of the slit position, (EAST to WEST): 0,1,...2) irow = Index of the pixel along the slit (SOUTH to NORTH): 0,1,… 3) px = shift in arcseconds across the planet, for the pixel in the center of the slit4) py = shift in arcseconds along the slit, of the pixels relative to the center pixel of the slit5) val = retrieved abundance [ppm for H2O, ppb for HCl, scaler for CO2]6) err = error [ppm for H2O, ppb for HCl, scaler for CO2]7) lon = longitude of that pixel8) lat = latitude of that pixel