| Abstract: | The code system containing the DELTA and the ADREA codes has been developed at the National Centre of Scientific Research (NCSR) “DEMOKRITOS” and performs mesoscale wind field calculations over terrains of high complexity. The code system follows a particular technique of discretization, according to which the ground can be treated with a resolution higher than the one used in the atmosphere. This technique, called “the high-resolution-ground-low-resolution-air” concept, offers to the code system the capability to reliably simulate the thermal air-ground interaction processes, keeping at the same time the computation storage and duration in reasonable levels. The above code system was applied to a high-resol ution representation of the Attika district, within a domain of 72 × 72 × 6.125 km3. Mesoscale wind field calculations were made within the framework of the APSIS Phase-A Intercomparison Exercise, using the atmospheric radiosonde and surface data of 25 May 1990. In this particular day, the greater Athens area was dominated by the daytime thermally driven local systems, generated along the coastlines of the peninsula. The application of the DELTA-ADREA system reproduced the above mesoscale influences and exhibited a favourable agreement with observations. |
