This is a README.txt regarding the data products of the MIPAS instrument on satellite Envisat
about Polar Stratospheric Cloud (PSC) type classification.

The dataset and the processsing chain is described in:

[1] Spang, R., Arndt, K., Dudhia, A., Höpfner, M., Hoffmann, L., Hurley, J., Grainger, R. G., Griessbach, S., Poulsen,
    C., Remedios, J. J., Riese, M., Sembhi, H., Siddans, R., Waterfall, A., and Zehner, C.:
    Fast cloud parameter retrievals of MIPAS/Envisat, Atmos. Chem. Phys., 12, 7135–7164,
    https://doi.org/10.5194/acp-12-7135-2012, 2012.

[2] Spang, R., Hoffmann, L., Höpfner, M., Griessbach, S., Müller, R., Pitts, M. C., Orr, A. M. W., and Riese, M.:
    A multi-wavelength classification method for polar stratospheric cloud types using infrared limb spectra,
    Atmos. Meas. Tech., 9, 3619-3639, https://doi.org/10.5194/amt-9-3619-2016, 2016.

[3] Spang, R., Hoffmann, L., Müller, R., Grooß, J.-U., Tritscher, I., Höpfner, M., Pitts, M., Orr, A., and Riese, M.:
    A climatology of polar stratospheric cloud composition between 2002 and 2012 based on MIPAS/Envisat observations,
    Atmos. Chem. Phys., 18, 5089-5113, https://doi.org/10.5194/acp-18-5089-2018, 2018.


The PSC classification files are in netCDF format and daily files (day of year 1...365/6) are prepared in corresponding
yearly folders from 2002 to 2012, April to October for the SH and Nov to April for the NH polar regions.

Various version of the dataset have been prepared, where the original classification method [2] is unchanged (class_V1.2.8)
but helpful parameters from meteorological analyses (T, p, h2o, T_ice etc.) and instrument parameter (e.g. satellite/observer
position, line of sight parameter) are added.

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*ATTENTION:*

      The version of the classification is part of the filenames but is NOT applied in the versioning of this repository:
      
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V1.0: PSC Classification original V1.2.8 with only limitted auxiliary data (ERAi: T, p, pv, theta)

      Original dataset of the MIPAS PSC classification, introduced in [2] and [3], cloud detection in [1]. 


V1.1: PSC classification  (includes ERAi parameter plus add-on: geometric tangent altitude ALT_L1B)

      Original dataset of the MIPAS PSC classification, introduced in [2] and [3].


V1.2: PSC classification plus ERA5 based Temperature and water vapour information along the line of sight (LOS)

      These add-ons are used to find the minimum T-T_ice spot or the most likely locaton for ice PSC formation.
      The information is used and described in [4].
    

V1.3: PSC classification plus additional ERA5 LOS parameter

      This is a slight update of V1.2 with some additional parameter regrading the minimum T-T_ice location
      along the LOS with respect to the tangentpoint and at the tangentpoint all based on ERA5 data (p,T,H2O)
      with 1x1 deg and 6 hourly resolution.


[4] Zou, L., Spang, R., Griessbach, S., Hoffmann, L., Khosrawi, F., Müller, R., and Tritscher, I.:
    A statistical analysis of the occurrence of polar stratospheric ice clouds based on MIPAS satellite observations
    and the ERA5 reanalysis, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-547, 2024.