
Ocean remote sensing requirements
OBSERVATIONS				OPTIMIZED REQUIREMENTS				THRESHOLD REQUIREMENTS
Code	Application	Variable	Type	HR(km)	Cycle	Time	Acc	HR(km)	Cycle	Time	Acc
ALTIMETRY
A	Mesoscale Variability	sea surface topography	Input	25	7d	2d	2cm	100	30d	15d	10cm
B	Large scale Variability (seasonal, tides, gyres)	sea surface topography	Input	100	10d	2d	1cm	300	10d	10d	2cm
C	Mean sea level Variations	sea surface topography	Input	200	decades	10d	1mm/year	1000	decades	10d	5mm/year
D	Absolute Circulation heat transport	sea surface topography	Input	100	NA	NA	1cm	500	NA	NA	5-10cm
E	Geoid Estimation	Geoid	Base	100	NA	NA	2 cm	500	NA	NA	~ 1cm
SURFACE WIND VECTORS
F	Wind-forced circulation	Wind field	Input	25	1d	1d	1-2m/sec 20°	100	7d	7d	2m/sec 30°
SEA SURFACE RADIATIVE
G	Ocean/ Atmosphere coupling	Sea surface temperature (radiometer)	Input	10	6h	6h	0.1°K (relative)	300	30d	30d	1°K
H	Ocean forcing	Short-wave irradiance	Input	200 km	1d	1d	15 W/m²	500 km	7d	7d	20-30 W/m²
REMOTE SALINITY
I	Circulation and Water Transport	Salinity	Input	200	10d	10d	0.1PSU	500	10d	10d	1PSU
SEA ICE
J	Ice Ocean coupling	Sea ice cover	Input	10	1d	0.125d	2%	100	7d	1d	10%
OCEAN COLOR
K	Upwelling to recirculation	Ocean color signal	Input	25	1d	1d	2%	100	1d	1d	10%
SURFACE WAVES
L	Sea state prediction	Significant wave height	Input	100	3h	3h	0.5 m	250	7d	12 h	1 m
M	Sea state prediction	Period and direction	Input	10	1h	2h	0.5 s 10°	30	6h	4h	1 s 20°

Footnotes:
A requires			Wave height + wind (EM bias correction) measured from altimeter
			Water vapor content / measured from on board radiometer
			Ionospheric content / measured from 2 frequencies altimeter
B requires in addition			Precise positionning system = accuracy 1-2 cm for spatial resolution of 100 km;
			need to address aliasing from solar tides with non-sunsynchronous orbits.
C requires in addition			Precise monitoring of transit time in the radar altimeter
A, B, C			Require repeat track at + 1 km = to filter out unknowns on geoid
A			Requires adequate sampling = at least 2 and better 3 satellites simultaneously
A, B, C			Requires long lifetime, continuity, cross calibration
D			Requires absolute calibration
E			Requires one-off missions with both high- and broad- resolution determination
F			Requirements on the wind field for sea state determination normally exceed
			sampling requirements for wind forcing
G			High resolution SST: new geostationnary satellite + combination with low satellite

Table B. A table of ocean remote sensing requirements. The requirements include consideration of climate applications
as determined by the OOPC and ocean forecasting/estimation as determined by GODAE.
The requirements beyond the climate module have not be detailed here.

Table A