Precipitable Water Vapor Tables from ECMWF ERA5 Re-Analysis for SOFIA FIFI-LS Flights

<h3>SOFIA Precipitable Water Vapor (PWV) Products for all flights with FIFI-LS between the year 2014 and 2022.</h3>

<p>
Each FITS file contains a HDU "DATA", which is a binary table extension with columns for
Precipitable Water Vapor (PWV), Longitude, Latitude and Atmospheric Pressure
as a function of in-flight time. The source for positional data
is the primary GPS sensor of SOFIA (see POSSRC keyword).
PWV values were derived from the ERA5 Re-Analysis from ECMWF
(Hersbach, H., 2020, <a href="https://doi.org/10.1002/qj.3803">DOI:10.1002/qj.3803</a>).
</p>

<p>
<b>Note:</b> For use of PWV values for atmospheric transmission correction
by the instrument pipeline software, a specific instrument dependent
conversion must be performed. Please refer to the respective
documentation in the SOFIA Redux module for FIFI-LS for further details.
</p>

<p>
Derivation of the ECMWF PWV values and specific instrument
correlations for FIFI-LS are explained in detail in, e.g.,
Fischer et al., 2021, <a href="https://doi.org/10.1088/1538-3873/abf1ca">DOI:10.1088/1538-3873/abf1ca</a> and
Iserlohe et al., 2021, <a href="https://doi.org/10.1088/1538-3873/abef76">DOI:10.1088/1538-3873/abef76</a>.
</p>

<p>
Percentiles, <em>Pk</em>, for given geographical position and flight altitude
of SOFIA and season of the observations are derived
from a 10 year statistics presented in
Iserlohe et al., 2022, <a href="https://doi.org/10.1088/1538-3873/ac82c5">DOI:10.1088/1538-3873/ac82c5</a>.
<em>Pk</em> means that there is a <em>k</em>% probability of observing a PWV value less than <em>Pk</em> in flight.
</p>

<p>
The FITS files also contain some water vapor maps of the region of the flight path for data validation purposes.
</p>