WIND FLOW SIMULATION OVER GREATER ATHENS AREA WITH HIGHLY RESOLVED TOPOGRAPHY

The code system containing the DELTA and the ADREA codes has been deve loped at the National Centre of Scientific Research (NCSR) ''DEMOKRITO S'' and performs mesoscale wind held calculations over terrains of hig h complexity. The code system follows a particular technique of discre tization, according to which the ground can be treated with a resoluti on higher than the one used in the atmosphere. This technique, called ''the high-resolution-ground-low-resolution-air'' concept, offers to t he code system the capability to reliably simulate the thermal air-gro und interaction processes, keeping at the same time the computation st orage and duration in reasonable levels. The above code system was app lied to a high-resolution representation of the Attika district, withi n a domain of 72 x 72 x 6.125 km(3). Mesoscale wind field calculations were made within the framework of the APSIS Phase-A Intercomparison E xercise, using the atmospheric radiosonde and surface data of 25 May 1 990. In this particular day, the greater Athens area was dominated by the daytime thermally driven local systems, generated along the coastl ines of the peninsula. The application of the DELTA-ADREA system repro duced the above mesoscale influences and exhibited a favourable agreem ent with observations.