Abstract:

Thermal humidity and airflow fields over the metropolitan area of Buenos Aires city (Argentina), for the period June 9-13, 1978, at 08:00, 14:00 and 20:00 AST have been analysed. This period was selected because of its little cloudiness (<3/8) and light winds (velocity < 4 m s -1 ) at one of the meteorological stations. The observations were provided by eight stations located in the area. The effect of the urban heat island and the influence of the greater water temperature appear in the thermal fields at 08:00 and 20:00. At 14:00 the opposite effect can be appreciated. The airflow fields at 14:00 show a rotation of the wind from north to south, through the east, during the period. At 08:00 and 20:00 there is no wind in the area. The mixing-layer height was also studied. This height was estimated using the upper air observations obtained from radiosonde ascents from Ezeiza Airport station and the daily maximum temperatures of the meteorological stations selected. In general, the fields of mixing height are similar to the thermal fields at 14:00, with urban values lower than suburban ones. © 1991.