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Nimbus-7 earth radiation budget calibration history. part 2: the earth flux channels
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Maschhoff, Robert H. Kyle, H. Lee Groveman, Brian S. Vallette, Brenda J. Hickey, John R. Hucek, Douglas Richard R. Ardanuy, Philip E. Penn, Lanning M. |
| Copyright Year | 1994 |
| Description | Nine years (November 1978 to October 1987) of Nimbus-7 Earth radiation budget (ERB) products have shown that the global annual mean emitted longwave, absorbed shortwave, and net radiation were constant to within about + 0.5 W/sq m. Further, most of the small annual variations in the emitted longwave have been shown to be real. To obtain this measurement accuracy, the wide-field-of-view (WFOV) Earth-viewing channels 12 (0.2 to over 50 micrometers), 13 (0.2 to 3.8 micrometers), and 14 (0.7 to 2.8 micrometers) have been characterized in their satellite environment to account for signal variations not considered in the prelaunch calibration equations. Calibration adjustments have been derived for (1) extraterrestrial radiation incident on the detectors, (2) long-term degradation of the sensors, and (3) thermal perturbations within the ERB instrument. The first item is important in all the channels; the second, mainly in channels 13 and 14, and the third, only in channels 13 and 14. The Sun is used as a stable calibration source to monitor the long-term degradation of the various channels. Channel 12, which is reasonably stable to both thermal perturbations and sensor degradation, is used as a reference and calibration transfer agent for the drifting sensitivities of the filtered channels 13 and 14. Redundant calibration procedures were utilized. Laboratory studies complemented analyses of the satellite data. Two nearly independent models were derived to account for the thermal perturbations in channels 13 and 14. The global annual mean terrestrial shortwave and longwave signals proved stable enough to act as secondary calibration sources. Instantaneous measurements may still, at times, be in error by as much as a few Wm(exp -2), but the long-term averages are stable to within a fraction of a Wm(exp -2). |
| File Size | 6320352 |
| Page Count | 118 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19940023478 |
| Archival Resource Key | ark:/13960/t9w140g5w |
| Language | English |
| Publisher Date | 1994-03-01 |
| Access Restriction | Open |
| Subject Keyword | Radiation Detectors Satellite Instruments Diurnal Variations Calibrating Annual Variations Earth Radiation Budget Nimbus 7 Satellite Satellite Observation Extraterrestrial Radiation Thermal Degradation Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
