Winter 2008
Flying high: JAIVEx benefits from SSEC aircraft instrument
The Scanning High-resolution Interferometer Sounder (S-HIS) is an advanced version of SSEC’s HIS instrument. The S-HIS was developed between 1996 and 1998 at SSEC with the combined support of the U.S. DOE, NASA, and the NPOESS Integrated Program Office. The S-HIS was initially designed to fly on an unmanned aircraft vehicle (UAV) with limited payload capacity. These goals led to a small, light-weight, and modular instrument with low power consumption. The S-HIS instrument now flies on a number of aircraft platforms including the NASA ER-2, the NASA DC-8, the Scaled Composites Proteus, and the NASA WB-57. On the Proteus and WB-57 aircraft, an upward (zenith) view is available, providing a means for upper atmosphere studies and at-altitude calibration verification.
The S-HIS is a cross track scanning airborne Fourier Transform Spectrometer (FTS) that measures emitted thermal radiation at high spectral resolution between 3.3 and 18 microns. The S-HIS field of view is 100 milliradians, providing a spatial resolution of 2 kilometers (at nadir) across a 40 kilometer ground swath from a nominal altitude of 20 kilometers (typical NASA ER-2 and WB-57 cruise altitude).
The S-HIS calibration techniques achieve the high radiometric accuracy needed for atmospheric state retrieval, calibration validation of satellite instruments, and spectroscopic applications. To verify the S-HIS calibration accuracy and provide direct NIST traceability of the S-HIS radiance observations, laboratory tests of the S-HIS and the NIST Transfer Radiometer (TXR) were successfully conducted earlier this year. An SSEC thermal chamber was used to simulate flight temperatures for the S-HIS instrument.
