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Space-Based Data Requirements for GOOS
The observing requirement specified for GOOS are based on in situ and satellite data. For satellite data GOOS will use both geostationary and polar orbiting satellites to achieve the necessary spatial resolution and to reduce the geophysical noise in climate signals. In situ data are necessary to provide calibration for the satellite sensors, to provide subsurface data, and to provide data where satellite coverage is poor. This page describes the applications, variables, and resolutions that have been specified for the space-based data.
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The table below shows the space-based data requirements for GOOS. These initial requirements have been compiled with particular reference to the needs of the Global Ocean Data Assimilation Experiment (GODAE). GODAE is a major numerical modelling experiment that will assimilate ocean data from in situ observations and satellites. GODAE is likely, in general, to be more demanding in terms of spatial and temporal resolution, but with decreased emphasis on the deep ocean and perhaps slightly weaker accuracy requirements.
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Global Observations of Ocean Circulation - Space-Based Data Requirements
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| Details |
Optimized requirements |
Threshold requirements |
| Code |
Application |
Variable |
Horizontal Resolution (km) |
Cycle |
Time |
Accuracy |
Horizontal Resolution (km) |
Cycle |
Time |
Accuracy |
| Altimetry |
A
|
Mesoscale variability
|
sea surface topography |
25
|
7 d
|
2 cm
|
2 d
|
100
|
30 d
|
15 d
|
10 cm
|
B
|
Large scale variability
|
sea surface topography |
100
|
10 d
|
2 cm
|
2 d
|
300
|
10 d
|
10 d
|
2 cm
|
C
|
Mean SL variations
|
sea surface topography |
200
|
> 10 yr
|
1 mm/yr
|
10 d
|
1000
|
> 10 yr
|
10 d
|
5 mm/yr
|
D
|
Circulation, heat transport
|
sea surface topography |
100
|
NA
|
1 cm
|
NA
|
500
|
NA
|
NA
|
5-10 cm
|
| Remote Salinity |
E
|
Circulation water transport
|
surface salinity |
200
|
10 d
|
0.1 PSU
|
10 d
|
500
|
10 d
|
10 d
|
1 PSU
|
| Scatterometry |
F
|
Wind-forced Circulation
|
surface wind field |
25
|
1 d
|
1-2 m/s 20E
|
1 d
|
100
|
7 d
|
7 d
|
2 m/s 30E
|
| Sea Surface Temperature |
G
|
NWP; climate, mesoscale models
|
Sea surface temperature |
10
|
6 h
|
0.1EK (relative)
|
6 h
|
300
|
30 d
|
30 d
|
1EK
|
| Sea Ice |
H
|
Ocean-ice coupling warning
|
sea ice extent, concentration |
10
|
1 d
|
2%
|
3 h
|
100
|
1 d
|
10 d
|
10%
|
| Ocean Color |
I
|
Biogeochemistry, transparency
|
ocean color signal |
25
|
1 d
|
2%
|
1 d
|
100
|
1 d
|
1 d
|
10%
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Footnotes:
A requires wave height + wind (EM bias correction) measured from altimeter, water vapor content measured from on board radiometer, and ionospheric content / measured from 2 frequency altimeter.
B requires precise positioning system with an accuracy of 1-2 cm for a spatial resolution of 100 km.
C requires precise monitoring of transit time in the radar altimeter.
A, B and C require repeat track at + 1 km to filter out unknowns on geoid.
A requires adequate sampling which implies at least 2, and preferably 3, satellites simultaneously.
A, B and C require long lifetime, continuity, cross calibration.
D requires absolute calibration.
F: The requirements on the wind field for sea state determination normally exceed sampling requirements for wind forcing
G: High resolution SST from new geostationnary satellite + combination with low satellite
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