Monitoring weather and climate from space

HIRS

The High-resolution Infrared Radiation Sounder (HIRS/4) is a 20-channel infrared scanning radiometer that will perform operational atmospheric sounding, to provide calibrated vertical profiles of temperature and humidity; information on cloud cover, cloud top height, cloud top temperature and cloud phase, as well as surface albedo. HIRS has 19 infrared channels (3.8-15 µm) and one visible channel. The swath width is 2160 km, with a 10 km resolution at nadir.

IR calibration of the HIRS/4 is provided by programmed views of two radiometric targets mdash; the warm target, mounted on the instrument baseplate, and a view of deep space. Data from these views provides sensitivity calibrations for each channel at 256 second intervals, if commanded. Internally generated electronic signals provide calibration and stability monitoring of the detector amplifier and signal processing electronics.

HIRS uses CO2 absorption bands for temperature sounding (CO2 is uniformly mixed in the atmosphere). In addition, the instrument measures water vapour, ozone, N2O and cloud and surface temperatures.

HIRS/4 Summary Budgets

  Scan Rate   6.4 secs  
  Scan Type   Stop and stare  
  Pixel IFOV   0.69° (circular)  
  IFOV size at Nadir   10 km  
  Sampling at Nadir   26 km  
  Earth View Pixels / Scan   56  
  Swath   ± 49.5°  
  Swath   ± 1092 km  
  Spectral Range   0.69 to 15 µm  
  Lifetime   Five years (three years design life)  
  Power   24 W  
  Size   410 mm x 460 mm x 690 mm  
  Mass   35 kg  
  Data rate   2.88 kbps  

HIRS/4 is manufactured by [External link] ITT Exelis in Fort Wayne, Indiana under contract to NASA.

For more in-depth information, see the and the , Section 3.2.2
 
Print Print | [Internal link]Contact Us | [Internal link]About this web site | Last Update : 22-08-2012 | NID-02 Top of page