The influence of the regional climate in a lagoon in northeastern Mexico

Abstract

The climate affects the Earth at three levels: the relationships between the Sun-Earth energy interaction, the regional climate by the troposphere-Earth relationship (basins) and the local climate by the climatic gradients in endo and exorreic basins. The information on coastal lagoons provided by the last two is scarce and has only been used to define local descriptive frameworks for particular study areas. As a result of this, this paper aims to determine the qualitative and quantitative influence of regional climate on the three local climates defined in an exorreic basin in the northwestern Gulf of Mexico at the level of regional climate. The coastal lagoon of Tampamachoco is located in one of these local climates. The regional climate affects the local climate and defines the seasons in tropical latitudes (the Gulf of Mexico), in accordance with the origin and amount of the rain. The seasons are defined with respect to the rainfall regimes presented in Köppen's classification, later modified by Garcia (1964), and corroborated with the frequency and intensity of the prevailing winds from 1922 to 1994. These are: 1) the season of northers: from November to February with an average of 222 mm, 2) the dry season: in March and April with an average of 92 mm and 3) the rainy season: from May to October with an average of 1071 mm. Three local climates are defined in response to an orographical factor, as BS₁, Aw₁ and Aw₂. Type Aw₁ corresponds to 35% of the basin and is located over the whole coastal plain, type Aw₂ makes up 55% over the leeward portion of the Sierra Madre Oriental and the Sierra de Tantima mountain ranges and type BS₁ makes up 10% over the windward portion of the Sierra de Tantima. The spatial and temporal differences in the rainfall over the whole basin produce two waterways with multiple sources as a result of the regional climate over the local climate, that affect the shape and hydrological behaviour of the lagoon. The Tuxpam River originates in the most humid climatic area and is a permanent supply to the lagoon with changes in discharge related to the seasons (March 695 m³/s, July 965 m³/s and September 1825 m³/s). The Santiago River, of which the supply is registered only in the rainy season, has its origin in a dry climatic area.