The NRT SST product was the result of a collaboration between SOG, that provides the data (link a MFSPP SST data) covering the eastern Mediterranean basin, and CMS that supplies the western Mediterranean images.

Data were received mainly from NOAA-14 and for limited periods (problems of noise on the frequencies dedicated to NOAA-14 transmission in Rome) from NOAA-12 or NOAA-15 satellites. NOAA-12 and NOAA-15 data were adjusted to NOAA-14 to eliminate the existing bias. Only NOAA-14 passes were acquired after June 1999.

The data were preliminary processed at SOG and CMS using apposite software (AVHRR data acquisition and processing). The SST was then computed from the brightness temperature of channel 4 and 5 of the AVHRR through the linear MCSST algorithm proposed by MacClain et al.(1985) at SOG and using a non linear algorithm at CMS, as described for example in Brisson et al. (1998).

A wide overlapping area was kept in both CMS and SOG data, in order to check and eventually eliminate biases between western and eastern Mediterranean sub-products (see also the MFSPP first year report, ).

A cloud detection algorithm, based on the different statistical (variance) and physical characteristics (spatial gradients) of clouds and sea surface temperatures, has been developed and applied to the images. A visual control and further elimination of cloudy pixels from the declouded images has been applied. La figura 1 si riferisce a questa parte

Daily maps were created composing single night pass images, in order to avoid the diurnal cycle and the skin heating effects. La figura 2 si riferisce a questa parte

Daily maps were binned at 1/8º over the grid of MFSPP model.
The binning procedure consists of a median filter with a window of 1/8° centred on the model grid points. Daily SST data were then weekly averaged in NRT mode



Fig.1 a) Example of SST image for the Eastern Mediterranean Sea as derived by the AVHRR. b) the same image after the cloud detection algorithm has been applied.

 

a b

c

 


Fig.2 c) Daily SST Image created from single passes (a) and (b). d) 1/8° binned map on model grid.

 

FLOW CHART