its SAR sensor, about 100 Mbit per second. These are datarates 
that no computer can cope with. Such data is first buffered on 
special recording devices and afterwards "reduced" to computer 
compatible tapes, CCT"s. In most cases, there computer compatible 
tapes are exchanged. Processing can be done from either the "high 
density" tape or CCT. Data from satellites can also be formatted 
in a photographic form. It depends upon the application, if 
photographs give sufficient information or not. 
Real-time case 
RS data from geostationary satellites, as well as polar orbiting 
satellites, is received at various ground stations and, almost 
in real time, delivered to users in the form of e.g. Sea Surface 
Temperature charts. This requires a processing system with a large 
throughput and of a high operational level. Distribution goes 
through fac-simile techniques. Also, meteorological data from 
satellites like Meteosat, is handled this way. 
Non real-time case, archives 
  
Since satellites produce data with high to very high data rates, 
archival systems for satellite data require more and more space. 
The development of new storage techniques (high density digital 
tape, VLP's) makes it possible to accomodat more data in less 
physical space. This, however, goes hand in hand with the 
development of increasingly complicated digital database 
management systems that should maintain the data accessible and 
retrieveable. 
Distribution systems 
  
In oceanographic applications, the distribution of data has not 
yet developed into a routine. Incidentally, oceanographers come 
across "interesting" images, but there is almost no routine 
distriburion of data to them. RS data distributers tend to be as 
operational as possible, which means that they have a limited 
number of dataproducts and processing techniques available. In 
many cases, these are not directed towards oceanographic applica- 
tions. Also it is mostly not possible to order cheap quick-looks 
to judge image quality, before ordering expensive imagery or 
digital products. 
Awareness on what is present in the RS data archives is generally 
low. Several RS data holders produce catalogues, but these are 
difficult to assemble, is they should contain information like 
cloud cover, in a reliable way. Such catalogues almost never reach 
the oceanographers' desk. 
Special oceanographic demands, aquisitions 
Oceanographers want to see the seasurface, as well as the more 
deeper parts. This means that they need information from several 
different wavelenghts, of which the optical range. It is a pity 
that ERS-1 will not carry an optical instrument. Now, the hopes 
of many oceanographers, especially those interested in biological 
or pollution matters, are for ERS-2 to carry such an instrument. 
Oceanographers cannot do a good job with one or two pictures once 
a year. In oceanography, it is important to have, besides the 
large geographical coverage, a sufficient temporal coverage. With 
that, the dynamics of phenomenae in the sea can be studied. 
746 
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