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Instrument: RA-2
Instrument details
Acronym
RA-2
Full name
Radar Altimeter - 2
Purpose
Ocean topography, significant wave height, wind speed on sea surface
Short description
two-frequencies (3.2 and 13.6 GHz)
Background
Evolution of RA on ERS-1 and ERS-2
Scanning Technique
Nadir-only viewing, continuous sampling along track
Resolution
20 km IFOV
Coverage / Cycle
Global coverage in 1 month for 30 km average spacing, or in 10 days for 100 km average spacing
Mass
110 kg
Power
161 W
Data Rate
100 kbps
Providing Agency
ESA
Instrument Maturity
Flown on operational programme
Utilization Period:
2002 to 2012-04-08
Last update:
Detailed characteristics
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 Active and radio-occultation sensor Radar altimeter
WIGOS Subcomponents
No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives Geoid Ocean dynamic topography Significant wave height
Secondary mission objectives Coastal sea level (tide) Gravity field
Opportunity objectives Ionospheric Vertical Total Electron Content (VTEC) Wind speed (near surface) 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
Coastal sea level (tide) 2 - very high Along-track only. Dual-frequency radar altimeter: Ku-band and supporting S-band or C-band to correct for ionospheric rotation
Geoid 2 - very high Long time series needed.. Along-track only. Geoid derived from multi-temporal analysis of radar altimetry data
Gravity field 4 - fair Partial information (geoid).. Along-track only. Gravity field derived from multi-temporal analysis of radar altimetry data
Ocean dynamic topography 2 - very high Long time for mapping.. Along-track only. Dual-freqency altimeter: Ku-band and supporting S-band or C-band to correct for ionospheric rotation
Significant wave height 2 - very high Along-track only. Ku-band radar altimeter
Wind speed (near surface) 5 - marginal Over sea only.. Along-track only. Radar altimeter. Wind speed estimated from the intensity of the backscattered signals
Ionospheric Vertical Total Electron Content (VTEC) 4 - fair Along-track only. Dual-frequency altimeter: Ku-band and supporting S-band or C-band to correct for ionospheric rotation