Satellite Altimetry Calibration and Validation

Satellite-based altimeters provide fundamental, large scale observations of sea surface height contributing fundamental advances in our understanding of the ocean’s role in the Earth’s climate system. Understanding changes in global mean sea level is critical for understanding the response of the ocean to a warming climate – both through the thermal expansion of the ocean and the melting of large ice regions both on land and in the ocean. As with all scientific observations, calibration of instrumentation is vital to ensure that measurements are accurate and reliable.

The IMOS Satellite Calibration and Validation Sub-Facility maintain GPS buoys in Bass Strait, providing the only southern hemisphere in situ calibration and validation locations. Deployments of these buoys enable sea level data to be directly compared to altimeter measurements, with data delivered to the Ocean Surface Topography Science Team (OSTST). These comparisons allow the absolute bias, the difference between altimeter and in situ measurements to be determined, ensuring that data produced from satellite altimeters are accurate and precise on a global scale.