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Instrument: HIRS/3
Instrument details
Acronym
HIRS/3
Full name
High-resolution Infra Red Sounder / 3
Purpose
Temperature/humidity sounding
Short description
Filter radiometer, 20 channels (including one VIS) [see detailed characteristics below]
Background
Evolution of HIRS/2 on TIROS-N and NOAA 6 to 14 (1978-2007). Operations on NOAA-15 stopped in 2009.
HIRS is part of the ATOVS sounding instrument suite (Advanced TIROS Operational Vertical Sounder)
Scanning Technique
Cross-track: 56 steps of 26 km s.s.p., swath 2200 km - Along-track: one line each 42 km every 6.4 s
Resolution
18 km at s.s.p.
Coverage / Cycle
Near-global coverage twice/day
Mass
35 kg
Power
24 W
Data Rate
2.88 kbps
Providing Agency
NOAA
Instrument Maturity
Flown on operational programme
Utilization Period:
1998-08-15 to 2013-04-10
Last update:
2017-03-29
Detailed characteristics
Wavelength
Wave number
Bandwidth
SNR @ specified input (for expected maximum temperature)
SNR @ specified input (for reference 300 K)
14.95 µm
669 cm-1
3 cm-1
40 @ 118 mW m-2 sr-1 cm
50 @ 150 mW m-2 sr-1 cm
14.71 µm
680 cm-1
10 cm-1
143 @ 96 mW m-2 sr-1 cm
223 @ 149 mW m-2 sr-1 cm
14.49 µm
690 cm-1
12 cm-1
127 @ 63 mW m-2 sr-1 cm
297 @ 148 mW m-2 sr-1 cm
14.22 µm
703 cm-1
16 cm-1
238 @ 63 mW m-2 sr-1 cm
475 @ 147 mW m-2 sr-1 cm
13.97 µm
716 cm-1
16 cm-1
436 @ 91 mW m-2 sr-1 cm
694 @ 146 mW m-2 sr-1 cm
13.64 µm
733 cm-1
16 cm-1
468 @ 111 mW m-2 sr-1 cm
599 @ 144 mW m-2 sr-1 cm
13.35 µm
749 cm-1
16 cm-1
624 @ 125 mW m-2 sr-1 cm
709 @ 142 mW m-2 sr-1 cm
12.47 µm
802 cm-1
16 cm-1
1751 @ 175 mW m-2 sr-1 cm
894 @ 134 mW m-2 sr-1 cm
11.11 µm
900 cm-1
35 cm-1
360 @ 54 mW m-2 sr-1 cm
1175 @ 117 mW m-2 sr-1 cm
9.71 µm
1030 cm-1
25 cm-1
894 @ 134 mW m-2 sr-1 cm
625 @ 94 mW m-2 sr-1 cm
7.33 µm
1364 cm-1
40 cm-1
120 @ 24 mW m-2 sr-1 cm
218 @ 43 mW m-2 sr-1 cm
6.52 µm
1534 cm-1
55 cm-1
38 @ 7.5 mW m-2 sr-1 cm
138 @ 27 mW m-2 sr-1 cm
4.57 µm
2188 cm-1
23 cm-1
577 @ 3.5 mW m-2 sr-1 cm
577 @ 3.5 mW m-2 sr-1 cm
4.52 µm
2210 cm-1
23 cm-1
740 @ 2.2 mW m-2 sr-1 cm
1070 @ 3.2 mW m-2 sr-1 cm
4.47 µm
2237 cm-1
23 cm-1
342 @ 1.4 mW m-2 sr-1 cm
735 @ 2.9 mW m-2 sr-1 cm
4.45 µm
2247 cm-1
23 cm-1
215 @ 0.86 mW m-2 sr-1 cm
710 @ 2.8 mW m-2 sr-1 cm
4.13 µm
2420 cm-1
28 cm-1
2208 @ 4.4 mW m-2 sr-1 cm
770 @ 1.5 mW m-2 sr-1 cm
4.00 µm
2500 cm-1
35 cm-1
2260 @ 4.5 mW m-2 sr-1 cm
545 @ 1.1 mW m-2 sr-1 cm
3.76 µm
2660 cm-1
100 cm-1
2900 @ 2.9 mW m-2 sr-1 cm
650 @ 0.65 mW m-2 sr-1 cm
0.69 µm
N/A
0.05 µm
1000 @ 100 % albedo
1000 @ 100 % albedo
Satellites this instrument is flying on
Note: a red tag indicates satellites no longer operational, a
green tag indicates operational satellites, a blue tag indicates
future satellites
Instrument classification
Earth observation instrument Passive optical radiometer or spectrometer Cross-nadir infrared sounder, possibly including VIS channels
WIGOS Subcomponents
No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives Atmospheric temperature Integrated Water Vapour (IWV) Specific humidity
Secondary mission objectives
Opportunity objectives Cloud top height Cloud top temperature Cloud type Downward long-wave irradiance at Earth surface Land surface temperature O3 Total Column Upward long-wave irradiance at Earth surface Upward long-wave irradiance at TOA Show all Show fewer
Tentative Evaluation of Measurements
The following list indicates which measurements can typically be
retrieved from this category of instrument. To see a full Gap Analysis by Variable,
click on the respective variable.
Note: table can be sorted by clicking on the column headers
Variable Relevance for measuring this variable Operational limitations Explanation
Atmospheric temperature 3 - high Cloud sensitive.. Coarse vertical resolution. Many MWIR and TIR channels in the 4.3 and 15 micrometer bands
Cloud cover 4 - fair Discontinuous coverage. MWIR and TIR channels
Cloud top height 2 - very high Discontinuous coverage. TIR channels in window and water vapour band (for emissivity) for temperature; and in CO2 band for atmospheric column above cloud top
Cloud top temperature 2 - very high Discontinuous coverage. TIR channels in window and water vapour band (for emissivity)
Cloud type 4 - fair Discontinuous coverage. MWIR and TIR channels
Downward long-wave irradiance at Earth surface 3 - high Cloud sensitive.. Highly indirect. MWIR and TIR channels including water vapour and CO2 bands
Land surface temperature 3 - high Cloud sensitive.. Coarse spatial resolution. MWIR and TIR channels in windows and absorption bands for atmospheric corrections
O3 Total Column 5 - marginal Cloud sensitive. TIR channel(s). Ozone lines in band around 9.7 micrometers
Sea surface temperature 2 - very high Cloud sensitive. MWIR and TIR window channels (cloud impact reduction, water vapour correction)
Specific humidity 3 - high Cloud sensitive.. Very coarse vertical resolution.. Middle troposphere only. TIR channels in the water vapour band around 6.3 micrometers
Integrated Water Vapour (IWV) 3 - high Cloud sensitive.. Inaccurate in high troposphere. TIR channels around 6.3 micrometers and in the 11 micrometers split window
Upward long-wave irradiance at TOA 4 - fair Spectral interpolation needed. MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in water vapour and CO2 bands around 4,3, 6.3 and 15 micrometers
Upward long-wave irradiance at Earth surface 3 - high Cloud sensitive.. Highly indirect. MWIR and TIR channels in windows around 3.7 and 11 micrometers, and in water vapour and CO2 bands around 4,3, 6.3 and 15 micrometers