Search Results

You are looking at 1 - 2 of 2 items for :

  • Author or Editor: Kory J. Priestley x
  • Journal of Atmospheric and Oceanic Technology x
  • Refine by Access: All Content x
Clear All Modify Search
Kory J. Priestley
,
Susan Thomas
, and
G. Louis Smith

Abstract

The Clouds and the Earth’s Radiant Energy System (CERES) scanning radiometers have been operating to make raster scans of the moon on a quarterly basis to validate the point response function for the three channels of flight models 1–4 aboard the Terra and Aqua spacecraft. Instrument pointing accuracy was verified by this method to 0.2° for the total channel of FM-3. The point response functions were computed from the lunar observations and were found to be nominal with the exception of the FM-2 window channel, which was found to have a region of high sensitivity. This anomaly is attributed to a delamination of the detector flake from the heat sink in that region. The influence of this anomaly is accounted for by the in-flight calibration and has no adverse effect on the application of the data.

Full access
G. Louis Smith
,
D. K. Pandey
,
Robert B. Lee III
,
Bruce R. Barkstrom
, and
Kory J. Priestley

Abstract

The Clouds and Earth Radiant Energy System (CERES) scanning radiometer was designed to provide high accuracy measurements of the radiances from the earth. Calibration testing of the instruments showed the presence of an undesired slow transient in the measurements of all channels at 1% to 2% of the signal. Analysis of the data showed that the transient consists of a single linear mode. The characteristic time of this mode is 0.3 to 0.4 s and is much greater than that the 8–10-ms response time of the detector, so that it is well separated from the detector response. A numerical filter was designed for the removal of this transient from the measurements. Results show no trace remaining of the transient after application of the numerical filter. The characterization of the slow mode on the basis of ground calibration data is discussed and flight results are shown for the CERES instruments aboard the Tropical Rainfall Measurement Mission and Terra spacecraft. The primary influence of the slow mode is in the calibration of the instrument and the in-flight validation of the calibration. This method may be applicable to other radiometers that are striving for high accuracy and encounter a slow spurious mode, regardless of the underlying physics.

Full access