Autor: |
Joe Bauer, James B. Young, John A. Mehrten |
Rok vydání: |
1998 |
Předmět: |
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Zdroj: |
SPIE Proceedings. |
ISSN: |
0277-786X |
DOI: |
10.1117/12.325633 |
Popis: |
The MODIS will be one of the primary instruments observing the earth on the EOS scheduled for launch in 1999. The on orbit radiometric calibration requirement for 3.5 micrometers to 14.3 micrometers spectral region is 1 percent with the sea surface bands at 0.5 percent. The on board calibrator blackbody (OBC BB) has a V groove cavity construction with polished low reflectance surfaces which provides an effective cavity emittance of 0.997 which has been characterized with a ground calibration blackbody system having an emittance > 0.999. The OBC BB provides an on orbit end to end system level radiometric calibration. Normally it operates at MODIS ambient temperature with a secondary mode of being heated to 315 K and then transitioning to ambient. Its temperature is monitored with 12 glass encapsulated thermistors whose initial temperature calibration is within 0.013 K traceable to NIST standards. The standard deviation of the 12 sensors during the cool down transition varies between 0.08 to 0.03 K with a weighted effective standard deviation of 0.042 K. The temperature profile will be graphically illustrated temporally and spatially. The relationship of MODIS viewing geometry related to BB is illustrated. |
Databáze: |
OpenAIRE |
Externí odkaz: |
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