This is the dataset of O3 in Mars atmosphere measured 
by ExoMars-TGO-NOMAD-UVIS and retrieved by the Planetary Atmospheres Research Unit of 
the Royal Belgian Institute for Space Aeronomy. 

This dataset is presented in "Ozone observed by TGO/NOMAD-UVIS solar
occultation: an inter-comparison of three retrieval methods" 
by A. Piccialli,  A.C. Vandaele, et al. 2022.

Each file name indicates the retrieval method:
FOEM: Full occultation Optimal Estimation Method 
OP: Onion Peeling
DOP: Direct Onion Peeling

Files are in the HDF5 format.

Each file contains:

Geometry
LST   = local solar time [hrs]
Ls    = solar longitude [degree]
lat   = latitude [degree]
lon   = longitude [degree]
orbit = file name of each occultation 
day = day of observation
month = month of observation
year = year of observation

Science
For each entry: [number of columns = number of occultations analyzed, number of rows = 600 (altitude grid)]

Nd_O3 = ozone number density [cm-3] 
Nd_O3_Err = error on ozone number density [cm-3]
z = altitude above aeroid [km]

Filtering (present only if relevant to the method):
DoF = Degree of Freedom 
DL  = detection limit [cm-3]
chi2_O3 = chi2 of the retrieval including ozone
chi2_no_O3 = chi2 of the retrieval without ozone

The filtering criteria Delta_chi2 described in our paper is derived as:
Delta_chi2 = chi2_no_O3/chi2_O3

We encourage you to contact us when you use this dataset or you have a question.
We kindly request the authors of any communication/publication using 
this dataset to let us know about it and to cite the reference Piccialli et al. 2022

Contact: Arianna Piccialli(e-mail: arianna.piccialli @ aeronomie.be)