Abstract

The Cross-track Infrared Sounder (CrIS) on the Suomi National Polar-orbiting Partnership (SNPP) and future Joint Polar Satellite System (JPSS) is a Fourier transform spectrometer that provides soundings of the atmosphere over 3 wavelength ranges: LWIR (9.14 - 15.38 μm); MWIR (5.71 - 8.26 μm); and SWIR (3.92 - 4.64 μm). Since it was launched on 29 October 2011, extensive post-launch calibration and validation activities have been carried out by CrIS sensor data record team (SDR), leading to the validated level maturity level of CrIS SDR product in February 2014. In this presentation, the CrIS SDR CrIS radiometric calibration accuracy and its stability are assessed by inter-comparing two years’ CrIS SDR with the radiances from the Atmospheric Infrared Sounder (AIRS) on NASA Aqua and Infrared Atmospheric Sounding Interferometer (IASI) on MetOp-A and –B. First, the CrIS radiance measurements on SNPP are directly compared with IASI on MetOp-A and -B at the finest spectral scale through the simultaneous nadir overpass (SNO) observations at the Polar Regions. Moreover, CrIS radiances are compared with AIRS on Aqua in 25 selected spectral regions through the SNO observations in both Polar and Tropical regions. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The time series and scene-dependent feature of BT differences are examined.

On the other hand, CrIS was switched into the full spectral resolution mode since 4 December 2014. It has an identical spectral resolution of 0.625 cm-1 in all three bands at the FSR mode (a total of 2211 channels). While the official CrIS SDR product was still processed and released as the normal resolution by Interface Data Processing Segment (IDPS), the NOAA/STAR CrIS SDR team off-line processed and released CrIS FSR SDR products. The inter-compassion of CrIS FSR SDR products with AIRS and IASI is also covered in this presentation.

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Aug 24th, 2:55 PM

Radiometric Calibration Stability Assessment for Soumi NPP CrIS: A Perspective from Two Years’ Inter-Comparison with AIRS and IASI

The Cross-track Infrared Sounder (CrIS) on the Suomi National Polar-orbiting Partnership (SNPP) and future Joint Polar Satellite System (JPSS) is a Fourier transform spectrometer that provides soundings of the atmosphere over 3 wavelength ranges: LWIR (9.14 - 15.38 μm); MWIR (5.71 - 8.26 μm); and SWIR (3.92 - 4.64 μm). Since it was launched on 29 October 2011, extensive post-launch calibration and validation activities have been carried out by CrIS sensor data record team (SDR), leading to the validated level maturity level of CrIS SDR product in February 2014. In this presentation, the CrIS SDR CrIS radiometric calibration accuracy and its stability are assessed by inter-comparing two years’ CrIS SDR with the radiances from the Atmospheric Infrared Sounder (AIRS) on NASA Aqua and Infrared Atmospheric Sounding Interferometer (IASI) on MetOp-A and –B. First, the CrIS radiance measurements on SNPP are directly compared with IASI on MetOp-A and -B at the finest spectral scale through the simultaneous nadir overpass (SNO) observations at the Polar Regions. Moreover, CrIS radiances are compared with AIRS on Aqua in 25 selected spectral regions through the SNO observations in both Polar and Tropical regions. The spectra from different sounders are paired together through strict spatial and temporal collocation. The uniform scenes are selected by examining the collocated Visible Infrared Imaging Radiometer Suite (VIIRS) pixels. Their brightness temperature (BT) differences are then calculated by converting the spectra onto common spectral grids. The time series and scene-dependent feature of BT differences are examined.

On the other hand, CrIS was switched into the full spectral resolution mode since 4 December 2014. It has an identical spectral resolution of 0.625 cm-1 in all three bands at the FSR mode (a total of 2211 channels). While the official CrIS SDR product was still processed and released as the normal resolution by Interface Data Processing Segment (IDPS), the NOAA/STAR CrIS SDR team off-line processed and released CrIS FSR SDR products. The inter-compassion of CrIS FSR SDR products with AIRS and IASI is also covered in this presentation.