There exist other methods to reconstruct an incomplete ensemble of data. Optimal interpolation is the best known and the most classical. Its big problem is its calculating time: for a typical ensemble of data, DINEOF is 30 times more rapid than optimal interpolation. This gap mainly reflects a different statistical methodology between the two different methods.

If the reconstruction of data allows a more judicious use of dynamic ocean models a practical problem needed to be resolved. In effect a researcher who for example studies anchovies in the Mediterranean will not throw herself into reconstructing satellite data related to the oceans’ surface temperature. She wants a finished product, and possibly ready made daily images.

The majority of these ‘non-specialists’ of satellite images use either raw data which thus has holes in the place of clouds or composite images provided by specialized institutions. The sum of consecutive data, these composite images have the advantage of being spatially complete…even if this artificial reconstruction can produce artifacts, traces of clouds or maintain holes if the clouds have remained for several days.

‘Our idea is to place on the market another high frequency product,’ continues Aida Alvera-Azcárate. ‘Thus my website produces a complete an daily image of the Mediterranean’s surface temperature, reconstructed on the basis of the data covering the six preceding months, obtained through the American satellites of the NOAA (National Oceanic and Atmospheric Administration). These satellites provide on a daily basis high resolution images of the whole of the North East Atlantic, including the Mediterranean. My programme receives them and reconstructs them, to eliminate the clouds. It can also be downloaded free of charge from my site, which offers a forum where the users can ask questions. Some twenty or so are already registered on this platform. This opportunity was very greatly welcomed. It also offers transparency which allows others to check our results and compare them to their own.’

If the DINEOF method has mainly today been used to reconstruct data concerning the Mediterranean, it has also been applied elsewhere. The Liège team has been contacted by researchers at the University of Madeira in the Canaries, who were interested in obtaining complete data for one of their sea campaigns. The ocean in the Canaries zone in effect has strong spatial and temperature variations. Incomplete of composite data cannot allow these areas where the temperature varies brutally to be precisely detected.