Extratropical planetary wave propagation characteristics from the ATSR global Sea Surface Temperature record.

The purpose of this paper is to examine the surface thermal signatures of extratropical baroclinic Rossby waves (a special class of planetary waves) in the ocean and measure their propagation speed. We show that the global sea surface temperature (SST) record produced by the Along Track Scanning Radiometer (ATSR) flown on the ERS-1 satellite between August 1991 and April 1996 contains clear evidence of wave propagation in all parts of the world oceans and at many latitudes. The characteristics of the propagating signals, which are examined in detail in the paper, match those expected for baroclinic Rossby waves. Not only can they be compared with those retrieved from altimeter observations of Sea Surface Height, but also they can help the understanding of the coupling between ocean and the atmosphere. We also look at how the signals vary in both space and time in the data record. We conclude that the ATSR data are a valuable source of information about the speeds of Rossby wave propagation, their variability, and how they might affect climate