Christine C. Molling

Deriving an inter-sensor consistent calibration for the AVHRR solar reflectance data record

A new set of reflectance calibration coefficients has been derived for channel 1 (0.63 μm) and channel 2 (0.86 μm) of the Advanced Very High Resolution Radiometer (AVHRR) flown on the National Oceanic and Atmospheric Administration (NOAA) and European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) polar orbiting meteorological satellites. This paper uses several approaches that are radiometrically tied to the observations from National Aeronautics and Space Administrations (NASAs) Moderate Resolution Imaging Spectroradiometer (MODIS) imager to make the first consistent set of AVHRR reflectance calibration coefficients for every AVHRR that has ever flown. Our results indicate that the calibration coefficients presented here provide an accuracy of approximately 2% for channel 1 and 3% for channel 2 relative to that from the MODIS sensor.

Calibrations for AVHRR channels 1 and 2: review and path towards consensus

The over three-decade-long data record from the Advanced Very High Resolution Radiometer (AVHRR) is ideal for studies of the Earths changing climate. However, the lack of on-board calibration requires that the solar channels be recalibrated after launch. Numerous calibration studies have been conducted, but significant differences remain among the calibrations. This study is one effort to outline a path towards consensus calibration of the AVHRR solar channels. The characteristics of the polar orbiting satellites bearing the AVHRRs, the AVHRR instruments and data are described as they are related to calibration. A review of past and current calibration studies is also presented and examples of their lack of consensus shown. A list of consensus items is then provided that, if followed by the AVHRR calibration community, should bring the various calibration methods to within the small percent difference required for long-term climate detection.

Using SURFRAD to Verify the NOAA Single-Channel Land Surface Temperature Algorithm

AbstractBecause of spectral shifts from instrument to instrument in the operational NOAA satellite imager longwave infrared channels, the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) has developed a single-channel land surface temperature (LST) algorithm based on the observed 11-μm radiances, numerical weather prediction data, and radiative transfer modeling that allows for consistent results from the Geostationary Operational Environmental Satellite-I/L (GOES-I/L), GOES-M–P, and Advanced Very High Resolution Radiometer (AVHRR)/1 through 3 sensor versions. This approach is implemented in the real-time NESDIS processing systems [GOES Surface and Insolation Products (GSIP) and Clouds from AVHRR Extended (CLAVR-x)], and in the Pathfinder Atmospheres–Extended (PATMOS-x) climate dataset. An analysis of the PATMOS-x LST against that derived from the upwelling broadband longwave flux at each Surface Radiation Network (SURFRAD) site showed that biases in PATMOS-x were approximatel...