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Instrument details
Acronym
OLS
Full name
Operational Linescan Systerm
Purpose
Cloud observation and day/night VIS imagery for fire detection
Short description
3-channel VIS/IR radiometer, including a day/night VIS channel implemented by a photomultiplier [see detailed characteristics below]
Background
Flown on all satellites of the DMSP series
Scanning Technique
Whiskbroom; 7325 pixels/line sampled cross-track for panoramic distortion correction at 0.5 km intervals. Swath 2960 km
Resolution
0.56 km. Cross-track sampling at 0.5 km intervals
Coverage / Cycle
Global coverage twice/day in both VIS and TIR
Mass
25 kg
Power
170 W
Data Rate
266 kbps
Providing Agency
DoD
Instrument Maturity
Flown on operational programme
Utilization Period:
1976 to 1978-03-19
Last update:
2021-06-22
Detailed characteristics
Central wavelength
Spectral interval
SNR or NEΔT @ specified input
0.71 µm (day/night)
0.47-0.95 µm
… @ … W m-2 sr-1 µm-1
0.75 µm
0.40-1.10 µm
… @ … W m-2 sr-1 µm-1
11.7 µm
10.0-13.4 µm
… K @ 300 K
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 Moderate resolution optical imager
WIGOS Subcomponents
Subcomponent 1 VIS/IR imager [in SSO] VIS/IR imager with day/night capability [in SSO]]
Mission objectives
Primary mission objectives Cloud cover Cloud top temperature Cloud type Fire fractional cover Secondary mission objectives
Opportunity objectives Fire radiative power Fire temperature Photosynthetically Active Radiation (PAR) Soil moisture at surface Wind (horizontal) 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
Cloud cover 4 - fair No specific limitation. VIS and TIR channels
Cloud top temperature 5 - marginal No specific limitation. TIR window channel(s)
Cloud type 4 - fair Daylight only. VIS and TIR channels
Fire fractional cover 4 - fair Cloud sensitive.. Coarse spatial resolution. VIS and TIR channels
Fire radiative power 5 - marginal Cloud sensitive.. Coarse spatial resolution. TIR channels
Fire temperature 5 - marginal Cloud sensitive.. Coarse spatial resolution. TIR channels
Photosynthetically Active Radiation (PAR) 5 - marginal Cloud sensitive. VIS channels, range undersampled
Sea surface temperature 5 - marginal Cloud sensitive. TIR window channel(s) around 11 micrometers .
Sea-ice cover 5 - marginal Cloud sensitive. VIS and TIR channels
Snow cover 5 - marginal Cloud sensitive.. Daylight only. VIS channel(s)
Soil moisture at surface 4 - fair Cloud sensitive.. Index only. VIS and TIR window channels. Soil moisture inferred from thermal inertia
Wind (horizontal) 5 - marginal Limited to high latitudes.. Cloud or water vapour tracers needed. TIR channel(s) around 11 micrometers window
Instrument: OLS