HIRS-2

High Resolution Infra Red Radiation Sounder/2 (HIRS/2)

The High Resolution Infra Red Radiation Sounder (HIRS/2) flies on the NOAA/TIROS-N type satellites and provides the basic 20 channel IR temperature and humidity soundings of the TOVS system. All HIRS/2 channels are used to provide information on temperature and humidity profiles, surface temperature, cloud parameters and total ozone. Calibration of HIRS/2 is performed every 40 scan lines, there is a gap of three scan lines in data coverage.. HIRS scans across track in a ‘stop and stare’ mode at a scan rate of 6.4 sec. There are 56 Earth Views per scan. The circular field-of-views have a diameter of 20 km at nadir. The swath covers ± 1080 km.

HIRS/2 sounder channel characteristics

ChannelCentre
Wave number
(cm-1)
Centre
Frequency
(mm)
Half Bandwidth
(cm-1)
Anticipated Max. Scene Temperature (K)Specified NEDN
(mW/m2/
sterad/cm-1)
166914.9532803.00
268014.71102650.67
369014.49122400.50
470314.22162500.31
571613.97162650.21
673313.64162800.24
774913.35162900.20
890011.11353300.10
910309.71252700.15
1079712.55162900.20
1113657.33402750.20
1214886.72802600.19
1321904.57233000.006
1422104.52232900.003
1522404.46232800.004
1622704.40232600.002
1723604.24232800.002
1822404.13283300.002
1926603.761003400.001
20145000.691000100 % Alb.0.10 % A