Abstract
Air temperatures under cold front conditions were recorded on July 10th 1969 inside and outside a secondary forest at Ducke Forest Reserve Air temperatures were measured at 2 towers and 8 corresponding levels ranging from 10 cm to 900 cm height. The absolute daily minimum air temperature recorded was 11.0°C, which is exceptionally low for Central Amazonia and 16.0°C below the yearly average air temperature at Manaus measured over a 45-year period of temperature records. The maximum 30-min range of air temperature was observed in the clearing (8.1°C), 7 meters above the ground. The strongest impact of air temperatures in the forest stand was recorded in the canopy area and in the ground stratum due to the formation of cold air cells and cold air sinks. The temperature profiles inside and outside the secondary forest at Ducke Forest Preserve during cold front conditions did not conform with the established temperature patterns in a tropical environment.