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Proceedings Paper

Detector noise characterization and performance of MODIS thermal emissive bands
Author(s): X. Xiong; A. Wu; N. Chen; K. Chiang; S. Xiong; B. Wenny; W. L. Barnes
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Paper Abstract

MODIS is a cross-track scanning radiometer that makes solar reflective and thermal emissive observations. It has 16 thermal emissive bands (TEB), a total of 160 individual detectors (10 for each spectral band), with wavelengths in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions. They are located on two cold focal plane assemblies (CFPA). MODIS TEB detectors were fully characterized pre-launch in a thermal vacuum (TV) environment using a laboratory blackbody calibration source (BCS) at temperatures from 170 to 340K. On-orbit the TEB detectors are calibrated using an on-board blackbody (BB). For nominal on-orbit operation, the on-board BB temperature is controlled at 290K for Terra MODIS and 285K for Aqua MODIS. Each TEB detector's noise equivalent temperature difference (NEdT) is often used to assess its on-orbit performance since this parameter is a key contributor to the calibration uncertainty. Because of its importance, the MODIS TEB detector NEdT is monitored on a daily basis at a fixed BB temperature and fully characterized on a regular basis at BB temperatures from 270 to 315K. In this paper, we describe MODIS TEB NEdT characterization activities, approaches, and associated results. We compare both prelaunch and on-orbit performance with sensor design specifications and examine the impact of detector noise characterization on the TEB calibration uncertainty. For general science applications and future reference purposes, a complete summary of TEB noisy detectors, identified pre-launch and on-orbit, is provided. Since launch in December 1999 and May 2002, Terra and Aqua MODIS have operated for more than 7 and 5 years, respectively. To date, 138 Terra MODIS TEB detectors and 158 Aqua MODIS TEB detectors continue to meet the sensor design NEdT requirements and enable high quality observations.

Paper Details

Date Published: 26 September 2007
PDF: 10 pages
Proc. SPIE 6677, Earth Observing Systems XII, 66770L (26 September 2007); doi: 10.1117/12.731305
Show Author Affiliations
X. Xiong, NASA Goddard Space Flight Ctr. (United States)
A. Wu, Science Systems and Applications, Inc. (United States)
N. Chen, Science Systems and Applications, Inc. (United States)
K. Chiang, Science Systems and Applications, Inc. (United States)
S. Xiong, Science Systems and Applications, Inc. (United States)
B. Wenny, Science Systems and Applications, Inc. (United States)
W. L. Barnes, Univ. of Maryland, Baltimore County (United States)

Published in SPIE Proceedings Vol. 6677:
Earth Observing Systems XII
James J. Butler; Jack Xiong, Editor(s)

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