MODIS Thermal Emissive Band Detector Bias

摘要

Two nearly identical MODIS instruments are currently operating in space: one on the Terra spacecraft launched in December 1999 and another on the Aqua spacecraft launched in May 2002. MODIS has a total of 36 spectral bands, 16 of which are the Thermal Emissive Bands (TEB) with wavelengths covering from 3.7μm to 14.4μm. Each TEB has 10 detectors aligned in the along-track direction with a spatial resolution of 1km. The 10 detectors view the Earth each scan over a 2330km wide swath. The curvature of the Earth creates a bowtie effect with each scan. At large scan angles consecutive scans will have several detectors with overlapping fields of view. This paper applies two approaches to investigate any potential bias between the 10 detectors of any TEB. A histogram approach is applied to large relatively uniform scenes over the Antarctic plateau, ocean and desert. Results are compared with an approach using the sets of matched detector pairs due to the bowtie effect. Terra and Aqua MODIS TEB long term trends in detector biases are presented and discussed.