Suomi NPP/JPSS Cross-track Infrared Sounder (CrIS): Calibration Validation With The Aircraft Based Scanning High-resolution Interferometer Sounder (S-HIS)

To better accommodate climate change monitoring and improved weather forecasting, there is an established need for higher accuracy and more refined error characterization of radiance measurements from space and the corresponding geophysical products. This need has led to emphasizing direct tests of in-orbit performance, referred to as “validation”. Validation typically involves (1) collecting high quality reference data from airborne and/or ground-based instruments during the satellite overpass, and (2) a detailed comparison between the satellite-based radiance measurements and the corresponding high quality reference data. The detailed comparison between the satellite-based radiance measurements and the corresponding measurements made from a high-altitude aircraft must account for instrument noise and scene variations, as well as differences in instrument observation altitudes, view angles, spatial footprints, and spectral response. Most importantly, for the calibration validation process to be both accurate and repeatable, the reference data instrument must be extremely well characterized and understood, carefully maintained, and accurately calibrated. The Scanning High-resolution Interferometer Sounder (S-HIS) meets and exceeds these requirements and has proven to do so on multiple airborne platforms, each with significantly different instrument operating environments.

The Cross-track Infrared Sounder (CrIS) on Suomi NPP, launched 28 October 2011, is designed to give scientists more refined information about Earth's atmosphere and improve weather forecasts and our understanding of climate. CrIS is an infrared Fourier transform spectrometer with 1305 spectral channels, and produces high-resolution, three-dimensional temperature, pressure, and moisture profiles. These profiles will be used to enhance weather forecasting models and they will facilitate improvements to both short and long-term weather forecasting. The first aircraft calibration validation campaign for Suomi NPP will be conducted in November 2012 with a primary objective of providing detailed validation of CrIS radiance observations and meteorological products. During this calibration validation campaign, the Scanning-High resolution Interferometer Sounder (S-HIS), the NPOESS Atmospheric Sounder Testbed-Interferometer (NAST-I), and the NPOESS Atmospheric Sounder Testbed-Microwave Spectrometer (NAST-M) will fly on the high altitude NASA ER-2 aircraft with underflights of Suomi NPP.

This presentation will include (1) an overview of the radiance calibration approach and accuracy of the aircraft validation data, (2) a detailed assessment of a single under-flight, and (3) a summary assessment of the CrIS spectral radiance observations for the underflights.