The NPOESS Radar Altimeter

A radar altimeter is currently scheduled to be launched on the third NPOESS platform in 2013. We will present an overview of the current plans for the instrument, orbit design, and accuracy requirements. We will comment on the capability of the mission to meet several science and operational goals, including assimilation into eddy-resolving ocean models and determination of global mean sea level (GMSL) change. The accuracy of the instrument calibration will directly effect the determination of GMSL change when linking the time-series from NPOESS to earlier missions like TOPEX/Poseidon, Jason-1, Envisat, and the Ocean Surface Topography Mission (OSTM). Because of this, we will also discuss the accuracy required of the NPOESS altimeter calibration in order to meet a goal of 0.5 mm/year for long-term GMSL change, and examine whether this may be possible if there is a gap between OSTM (or another altimeter science mission) and NPOESS.