PROCEEDINGS ARTICLE | November 19, 2012
Proc. SPIE. 8533, Sensors, Systems, and Next-Generation Satellites XVI
KEYWORDS: Staring arrays, Mirrors, MODIS, Sensors, Calibration, Black bodies, Radiometry, Space operations, Temperature metrology
MODIS has 16 thermal emissive bands (TEB) with wavelengths ranging from 3.7 to 14.4 μm. MODIS TEB are calibrated on-orbit by a v-grooved blackbody (BB) on a scan-by-scan basis. The BB temperatures are measured by a set of 12 thermistors. As expected, the BB temperature uncertainty and stability have direct impact on TEB calibration quality and, therefore, the quality of the science products derived from TEB observations. Since launch, Terra and Aqua ODIS have successfully operated for more than 12 and 10 years, respectively. Overall performance of each on-board BB has been satisfactory, meeting the TEB on-orbit calibration requirements. The first VIIRS instrument was launched on-board the Suomi NPP spacecraft on October 28, 2011. It has successfully completed its initial Intensive Calibration and Validation (ICV) phase. As a followed-up instrument to MODIS, VIIRS has 7 TEB, covering wavelengths from 3.7 to 12.0 μm. Designed with strong MODIS heritage, VIIRS uses a similar BB for its TEB calibration. Like MODIS, VIIRS BB is nominally controlled at a constant temperature. Periodically, a BB Warm-Up and Cool-Down (WUCD) operation is performed, during which the BB temperatures vary from instrument ambient (temperature) to 315 K. Following a brief review of MODIS and VIIRS BB operation strategy, this paper examines and compares their on-orbit performance in terms of BB temperature scan-to-scan variations during sensor nominal operations as well as during periodic BB WUCD operations. In addition, this paper shows the noise characterization results for the closely matched MODIS and VIIRS spectral bands.
