Instruments
Instrument Measurement/Purpose Frequency Accuracy
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Dual-Frequency Height of satellite above the sea, 13.6GHz 2.4 cm
TOPEX Altimeter wind speed, wave height, ionospheric altitude
correction
TOPEX microwave Total water vapor along the path viewed 18.0 GHz 0.2-g/cm2
Radiometer by the altimeter; this mesure corrects 21.0 GHz water-vapor
altimeter data for pulse delay due to 37.0 GHz density
water vapor (equivalent
to 1.2 cm)
Single-Frequency Heigh of satellite above the sea, wind 13.65GHz 2.5 cm
POSEIDON speed, wave height altitude
Altimeter