The benefits of high spectral and temporal resolution imaging sounders for the operational systems of the future have been widely recognized by NOAA and the weather satellite community for many years. This recognition of the importance of sounder data for improving nowcasts and forecasts of severe weather events of all kinds led to the successful development of the GIFTS advanced sounder (Geosynchronous Imaging Fourier Transform Spectrometer) under the NASA New Millennium Program and to the initial commitment of NOAA to a similar advanced sounder for GOES-R. Cost Benefit studies showed that the sounder would contribute about half of the large societal benefit of the new GOES-R system. Unfortunately, perceptions of system development and resource risks have led to decisions delaying implementation of the operational sounder until GOES-T. Unless other actions are taken to acquire advanced sounding data, much of the benefit of the new system for protecting the populace would be delayed for a decade. However, it is not too late; there are options under consideration.

Both GIFTS and the sounders designed by three competing industries for GOES-R under the HES (Hyperspectral Environmental Suite) program are capable of providing huge advances over the current GOES sounder. Like the ABI (Advanced Baseline Imager), increases in overall information content by factors of 10 to 100 will be captured. For ABI, the horizontal detail is increased over the current GOES imager by a factor of 4 and temporal coverage rates are increased by a factor of 5, yielding an overall factor of 20 in spatial/temporal resolution. ABI also increases the spectral information content by increasing the number of channels from 5 to 16. However, ABI is still not able to resolve the vertical dimension, even as well as the current GOES system. Vertical resolution is crucial to characterizing atmospheric stability and severe weather. The advanced sounder options would provide a vertical resolution that is 3 times higher than the current GOES sounder, an advance needed to meet future national and WMO observing requirements. In addition, the sounder options would provide major spatial and temporal advances as needed for compatibility with the new high resolution imaging capabilities of ABI. For example, the GIFTS design offers an overall factor of 100 improvement in spatial and temporal sampling over the current sounder, including its improved vertical resolution. And these sounder options can be provided without inordinate technological or cost risk.

An attractive approach for providing timely sounding data prior to an expected operational implementation on GOES-T is to fly demonstration sounders. This option has been recommended by the National Research Council “Decadal Survey” released in January and by the NOAA Analysis of Alternatives following the cancellation of the sounder program for GOES-R. The payoffs of proceeding with sounding as early as possible include: (1) societal benefits that significantly exceed the cost, (2) reduced technical, data handling, and cost risks for the future operational system, and (3) fulfillment of a key US leadership role in the international Global Earth Observations System of Systems (GEOSS). The accomplishments of the GIFTS program under joint NASA and NOAA support make it possible to plan for the first demonstration by as early as 2012. In addition, progress under the HES program lays the groundwork needed to proceed with a prototype of the ultimate operational sounder. Serious priority should be given to planning for demonstrations as soon as possible.