The Contribution of 18 Years of Altimetry to the Understanding of Oceanic Planetary Waves

In the past 18 years, our knowledge of that particular class of oceanic planetary waves also known as Rossby waves has improved significantly. Before the advent of altimetry they were already an important dynamical concept with a good theoretical understanding, but supported by very few, sparse observations; now they are a well-documented phenomenon, recorded in many different parameters in all ocean basins. Though some of this advance comes from reanalysis of old data and model output, the greatest impetus has been the wide availability of high accuracy satellite datasets, especially altimetric ones including those from ESA’s ERS-1, ERS-2 and Envisat missions. This paper illustrates what we have learnt on oceanic planetary waves during these 18 years, and summarises the questions still challenging observers and theoreticians today.