The new millennium ushered in an exciting opportunity to modernize severe weather observing from geosynchronous orbit.  The NASA/NOAA Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) project was formally initiated during the holiday season of December 1999. In the nearly eight years since that announcement, the GIFTS program has persevered through the successful completion of the Engineering Development Unit and gained new life as more and more scientists in the community advocate and support flying the sensor. The opportunity ushered in by the new millennium may finally be realized and not a moment too soon. When the GIFTS Imaging sounder capability gets into orbit, we expect to see significant improvements in the quality and timeliness of severe weather warnings from a combination of better nowcasts and numerical model forecasts.

The GIFTS concept was proposed to NASA's New Millennium Program (NMP) in 1999 by a team of scientists and engineers from NASA Langley Research Center (LaRC), the University of Wisconsin-Madison's Space Science and Engineering Center (SSEC), and Utah State University's Space Dynamics Laboratory (SDL). The GIFTS program also garnered support from the National Oceanic and Atmospheric Administration (NOAA) and the Department of Defense through the Office of Naval Research (ONR). Following the selection of GIFTS in December 1999 as the NMP Earth Observing 3 mission, a three-way agency partnership between NASA, NOAA, and ONR began, with each agency supporting various tasks in the GIFTS program.

NASA's overall goal for NMP is to develop and test technology for use in future space missions. Combining new and emerging sensor and data processing technologies, GIFTS will demonstrate several essential elements of an advanced optical remote sensing instrument, such as an imaging interferometer with significantly improved radiometric performance and enhanced cryogenic coolers. GIFTS also provides an opportunity to test practical, efficient ways to transmit large amounts of data to a ground processing system at a rapid rate. The ability to not only handle but assimilate substantial quantities of data at this rate is essential preparation for future instruments.

NOAA sponsored GIFTS research efforts to develop, evaluate and validate GIFTS data retrieval and assimilation techniques and products. NOAA also supports the evolution and demonstration of concepts, tools, and technology for future products and sensor systems. Specifically, NOAA views GIFTS as an opportunity to explore the advantages and implications of a geostationary hyperspectral sounder before launching an operational version.

The Department of Defense Office of Naval Research commitment was to launch the GIFTS sensor as part of the GIFTS-IOMI mission with a demonstration of geostationary observation over the Indian Ocean. This commitment to launch GIFTS was later withdrawn by the Navy, leading to a descoping of the overall mission objectives. However, through the Multidisciplinary Research Program of the University Research Initiative (MURI), ONR has funded a number of research projects in support of GIFTS. This ONR research effort has three main long-term goals:

  • to develop algorithms that can handle the challenges of hyperspectral data retrieval.
  • to determine where the most useful data in the data stream lie and to develop efficient methods for extracting the information content, thereby reducing the overall data volume.
  • and to use hyperspectral data to identify surface characteristics, formulate atmospheric profiles, and to assess the quality of coastal waters.

NASA LaRC coordinates the interagency collaboration by providing overall program management. Personnel at LaRC lead measurement concept development, systems engineering, planning for payload and mission operations, designing on-board data processing tools, validation of research products generated with GIFTS data, and efforts to archive and distribute GIFTS data and scientific products. The recent construction of the GIFTS Engineering Development Unit was also managed by LaRC.

Serving as the main instrument developers, SDL built and designed the key to the measurement technology, the Large area Focal Plane Array (LFPA). The LFPA consists of complex detectors that generate power when exposed to radiant energy. The large active area of the detector arrays facilitates parallel sensing and gives GIFTS the measuring power of more than 16,000 individual Fourier Transform Spectrometers. SDL also built the GIFTS Engineering Development Unit and conducted the thermal vacuum testing of GIFTS at their facilities. In addition, SDL develops ground data processing systems.

SSEC has not only been involved in the design and development of the GIFTS instrument, but we have also been investigating the science and products that the new technology will afford. SSEC engineers have developed the on-board calibration system for GIFTS; GIFTS uses two blackbodies run at two different temperatures in combination with views of deep space. This highly accurate system will allow for more accurate measurements from the instrument, thereby improving our ability to create useful science and products. GIFTS will deliver an unprecedented amount of data, and SSEC researchers are looking at how best to process and archive the data; SSEC's own Data Center provides an excellent resource for best data practices. Additionally, SSEC scientists have been developing and validating retrieval algorithms, conducting studies related to NWP modeling and forward modeling, investigating how best to derive winds from satellite radiances using hyperspectral data, examining topics such as visibility and stability for the study of convective weather phenomena.

All three partners were involved in the GIFTS EDU Measurement Experiment, a field campaign designed to calibrate and validate the GIFTS instrument against the Atmospheric Emitted Radiance Interferometer (AERI), a ground-based instrument. Although designed to look down through the atmosphere from space, GIFTS looked up through the atmosphere from the ground, similar to the AERI. Results from this experiment will help to underscore GIFTS's usefulness in making highly accurate measurements of the atmosphere.

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