Influence of the air temperature oscillation on the ecosystem of the Atlangatepec Dam, Tlaxcala, México.

Abstract

From 1951 to 1998, air temperature records were analyzed in the Atlangatepec Dam, in Mexico Central Basin, in order to determine annual temperature variability, setting out from its oscillation. Oscillation average amplitude was 1.2°C per year in 6.3% of the cases. In the 74.4% of the cases, the same average amplitude was 0.2°C per year. In the rest of the cases it was stable. More than a half of the years (57%) with an average warming trend of 0.8°C, coincided with El Niño events. In some of the years (34%), during La Niña events, a temperature with trend to the -0.4°C average cooling was recorded. Non-parametrical linear statistics techniques, time series and time series correlations were employed to analyze air temperature oscillation. The study period was of 48 years. Two types of periods were detected: a) 10.6 to 2.6 periods, and b) 2.2 years. The first periods were intimately related with solar activity, and the second with cuasi-biennal oscillation. Estimated temperature delay time was in average, a year. The same temperature delay time with respect to solar activity was in average two years.