TCOM-HF : Daily global gap-free stratospheric hydrogen fluoride (HF) profile data set based on TOMCAT CTM and Occultation Measurements

<p><strong>Methodology:&nbsp; TOMCAT simulation is performed at T64L32 resolution for the 2000-2024 time period. Collocated hydrogen fluoride (HF) profiles are divided in five latitude bins: SH polar (90S-50S), SH mid-lat (70S-20S), tropics (40S-40N), NH mid-lat (20N-70N) and NH polar (50N-90N). Initially, model-measurement&nbsp; differences are calculated for each zonal bins (51 height levels, 10km to 60km). Note that if enough ACE measurements are not avaliable for a particular level then data is purely based on TOMCAT simulated output field. Separate XGBoost regression models are trained for the&nbsp; differences between TOMCAT and measurements at each level for a given latitude bin. XGBoost model is then used to estimate error corrections for all the TOMCAT grids.&nbsp; TOMCAT output sampled at 1.30 pm local time at the equator. Estimated corrections for a given model grid that are added to the original TOMCAT simulated day and night time hydrogen fluoride profiles. Height resolved data are then interpolated on 28-pressure levels (300 - 0.1hPa). For overlapping latitude bins, we use averages and then calculate daily zonal mean values.&nbsp; For more details see attached presentation. Previous version use both HALOE and ACE data. Here only ACE data is used.</strong></p> <p><strong>Dataset also includes two files containing daily mean zonal mean hydrogen fluoride&nbsp; profiles on height (10-50 km) and pressure (300-0.1 hPa) levels:</strong></p> <p><strong>zmhf_TCOM_hlev_T2Dz_2000_2024.nc &ndash; height level data (10 to 50 km)</strong></p> <p><strong>zmhf_TCOM_plev_T2Dz_2000_2024.nc &ndash; pressure level data (300 to 0.1 hPa)</strong></p> <p><strong>Daily 3D profiles on height and pressure levels would be made available on request.</strong></p>