Autocorrelation scales of the SST distribution and water masses stratification in the Channel of Sicily

A 1-yr-long series of Advanced Very High Resolution Radiometer sea surface temperature (SST) images is used to study the SST distribution in 1992 over the Channel of Sicily. Time- and spatial scales of the SST are studied by estimating the SST autocorrelation function directly from satellite images. SST timescales vary from 1 week to 45 days, with lower values in areas of intense upwelling. Spatial scales of the SST show seasonal variations with values from 80 to 300 km, with higher values during the summer. Oscillation s with periods from 11 to 35 days modulate the annual variability of the SS T spatial scales. The first four internal radii of deformation are estimate d on the basis of climatological density profiles. The first internal radiu s varies from 7 km during the winter to 14 km during the summer. It is show n that, although differences between horizontal scales of the SST and inter nal radii of deformation exist, the annual variability of the SST spatial s cales can be interpreted in terms of seasonal variations of the first Rossb y radius of deformation.