P1.35 Advances in Compression of Ultraspectral Sounder Data

In the era of contemporary and future ultraspectral sounders such as Atmospheric Infrared Sounder (AIRS) (Aumann et al. 2001), Cross-track Infrared Sounder (CrIS) (Bloom 2001), Infrared Atmospheric Sounding Interferometer (IASI) (Phulpin et al. 2002), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) (Smith et al. 2002), and Hyperspectral Environmental Suite (HES) (Huang et al. 2003), better inference of atmospheric, cloud and surface parameters is feasible. An unprecedented amount of three-dimensional (3D) ultraspectral data, consisting of two spatial and one spectral dimension, is produced by the ultraspectral sounders. For example, the HES is the next-generation NOAA/NESDIS Geostationary Operational Environmental Satellite (GOES) sounder, slated for launch in 2013. It would be either a Michelson interferometer or a grating spectrometer, with high spectral resolution (over one thousand infrared channels with spectral widths on the order of 0.5 wavenumber), high temporal resolution (better than 1 hour), high spatial resolution (less than 10km) and hemispheric coverage. Given the large volume of 3D data that will be generated by an ultraspectral sounder each day, the use of robust data compression techniques will be beneficial to data transfer and archive. There exist differences between ultraspectral sounder data and hyperspectral imager data in terms of application areas and subsequent user constraints on the data compression. The hyperspectral imager data (e.g. the well-known AVIRIS data (Abousleman 1999)) is in the visible or near-infrared regions with major application categories of anomaly detection, target recognition and background characterization (Shaw et al. 2003). Lossy compression is usually acceptable for imager data as long as the tolerance limits in application-specific metrics are met (Saghri et al. 1995). These metrics include those that signify scientific loss for end users (Qian et al. 2001; Ryan et al. 1998), content-independent metrics (Shen et al. 1993), and even visual comparisons (Eckstein et al. 2000). On the other hand, the ultraspectral sounder data is in the infrared region with the main purpose of retrieving atmospheric temperature, moisture and trace gases pro-