Observation of Sea Level Change from Satellite Altimetry

This chapter focuses on satellite altimetry and considers the errors in those measurements, especially errors that take the form of a long-term drift. The first point to make about satellite altimeter data is that they are not simply the product of an instrument but come from a measurement system. Several different observations need to be made to produce high-quality sea surface heights, and maintaining the quality of the final height observations requires high performance by all components of the system. The chapter discusses those components and addresses the errors associated with each component, paying particular attention to whether a given component of the system might be prone to drift errors. Understanding how altimeter range measurements are collected and converted to sea-level measurements is conceptually straightforward, although the details are complex. The satellite transmits a radar pulse toward the ocean surface. After passing through the atmosphere, the pulse arrives at the atmosphere/ocean boundary, interacts with the ocean, and is then reflected back toward the satellite, again passing through the atmosphere