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Widefield Radiometer

NSSDCA ID: 1960-016A-01

Mission Name: TIROS 2
Principal Investigator:Dr. Rudolf A. Hanel


The TIROS 2 low-resolution, nonscanning, two-channel radiometer measured the thermal and reflected solar radiation from the earth-atmosphere system. The radiometer consisted of two detectors - one black and one white thermistor bolometer. Each of the detectors was mounted in the apex of a highly reflective mylar cone. The black detector responded equally to reflected solar radiation and long-wave terrestrial radiation (0.2 to 50 microns). The white detector reflected solar and visible radiation and measured only long-wave thermal radiation (5 to 50 microns). The optical axis of each detector was parallel to the satellite spin axis. The field of view of the detectors when viewing the earth directly below the satellite was a circle of 832 km diameter (50-deg field of view). The area was within the field observed by the wide-angle television camera, and thus a direct measure of the heat balance of the earth-atmosphere system viewed in any of the pictures was provided. The radiation data were recorded on a continuously running endless loop magnetic tape that completed its cycle in about 100 min. Data older than 100 min were erased as newer data were recorded. The experiment performed normally, but the quality of the data was very poor because the sensitivity of the detectors was lower than expected. There was also excessive thermal coupling brtween the radiometer detectors and the satellite. The white detector dit not totally reflect the solar radiation or absorb the long-wave terrestrial infrared emission. Consequently, the collected data were too ambiguous for reduction or analysis. The experiment is described in greater detail in NASA document TN D-614, 'The TIROS Low Resolution Radiometer.' Identical experiments were flown on TIROS 3 and 4.

Alternate Names

  • TIROS2/WidefieldRadiometer

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Earth Science: Atmospheric Dynamics

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Rudolf A. HanelPrincipal InvestigatorNASA Goddard Space Flight Center
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