Assessment of Elevation Measurements of Antarctica and Greenland from HY-2B Altimeter Data

The radar altimeter onboard China's HY-2B satellite was launched in October 2018. In this paper, the precision of the HY-2B elevation measurements over the Antarctica ice sheet (AIS) and the Greenland ice sheet (GrIS) is assessed through crossover analysis. The TFMRA (threshold first maximum re-tracker) algorithms is applied to retrack the waveforms of HY-2B altimeter. The precision of the HY-2B altimeter elevations is found to vary as a function of the threshold of the surface slope from
$\sim 48 \text{ cm}$
to
$\sim 51\text{ cm}$
over the AIS, and from
$\sim 23\text{ cm}$
to
$\sim 34 \text{ cm}$
over the GrIS. When compared with results obtained from time-coincident SARAL altimeter, the standard deviation of the crossover differences between the SARAL and HY-2B altimeters varies from
$\sim 68 \text{ cm}$
to
$\sim 101 \text{ cm}$
over the AIS, and from
$\sim 56\text{ cm}$
to
$\sim 102\text{ cm}$
over the GrIS.