Abstract

ANGEL-MERAZ, E del; VELEVA, L  and  ACOSTA-ALEJANDRO, M. Atmospheric aggressiveness based on the time of wetness of the tropical humid climate of the state of Tabasco. Universidad y ciencia [online]. 2009, vol.25, n.2, pp.111-120. ISSN 0186-2979.

The combination of data in the relative humidity-temperature atmospheric complex (CT-HR) plays a very important role in the development of experiments and in physical, chemical or biological processes. The daily changes in the CT-HR, as well as the time of wetness of different environments, allow making a detailed analysis to explain the process and rate of degradation of materials, particularly metals and alloys. A statistical and systematic study of the CT-HR was carried out in this study, based on the correlation of historical data of daily values of temperature (T) and relative humidity (HR) for the period 2000-2003, for two humid tropical climate environments located in the state of Tabasco. These two regions were characterised as urban (Villahermosa) and marine-coastal (Paraiso). The statistical analysis of the CT-HR showed a different behavior for the two regions. In the case of the urban atmosphere, the values of HR and T displayed marked diurnal changes that were constant throughout the year, with typical variations corresponding to the dry and rainy periods. The marine-coastal atmosphere presented a HR and a T similar to those of the urban atmosphere during the dry months. However, the behavior of the CT-HR did not present notable changes during the rainy season. According to norm ISO 9223, the annual value of the time of wetness indicates that the marine-coastal atmosphere may be considered to be very aggressive (category τ₅, 7470-8391 h year^-1), and the urban atmosphere aggressive (category τ₄, 4603-5741 h year^-1).

Keywords : Atmospheric corrosion; time of wetness; humid tropical climate; corrosion of metals.