Reanalyzed daily IASI/Metop-A ULB-LATMOS ammonia (NH3) L2 product (total column)

The reanalyzed IASI/Metop-A daily ammonia (NH3) total column dataset (ANNI-NH3-v2.2R-I), described in [Van Damme et al.](https://www.atmos-meas-tech.net/10/4905/2017/) (2017) includes the results of a flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. With this method: (1) complete temperature and humidity vertical profiles can be accounted for, (2) third‐party NH3 vertical profile information can be used, and (3) a full measurement uncertainty characterization is provided. Separate neural networks were trained for land and sea observations. ANNI-NH3-v2.2R-I relies on ERA-Interim ECMWF meteorological input data, along with surface temperature retrieved from a dedicated network, rather than the operationally provided Eumetsat IASI Level 2 data used for the standard version, which is also available on AERIS Website [NH3_standard](https://en.aeris-data.fr/metadata/?dc9dcce0-9324-451b-8d79-2d6df3094068). Recommendations for post-filtering the data and for averaging data in time or space are formulated in [Van Damme et al.](https://www.atmos-meas-tech.net/10/4905/2017/) (2017). The dataset is available on a global scale from October 2007. For inter-annual comparisons and trends analyses, this dataset can be used. The dataset is available on a global scale from January 2008 till December 2016. The homogeneous record of reanalysed NH3 columns is only provided until end of 2016 because of a change in the IASI Level 1 information treatment in 2017 for Metop-A.

Current Version: V2.2.0R-I, available since 2018-06-15