Resumo

CAMPOS-ARANDA, Daniel Francisco. Search of Trends in Annual Rainfall of the State of Zacatecas, Mexico, in 30 Records over 50 Years. Ing. invest. y tecnol. [online]. 2015, vol.16, n.3, pp.355-368. ISSN 2594-0732.

For Mexico, it has been predicted that climatic change will generally decrease precipitation and increase the mean temperature. In this paper the annual rainfall of the state of Zacatecas, Mexico was studied. Two approaches were used to look for climatic trends: the first one, a statistical approach to detect trends and/or changes in the mean, which means a loss of homogeneity in the records analyzed; the second one, a quantitative approach which consists in evaluating the ratio of the recent average precipitation to the long run, to observe if it deviates from the unit. To estimate a stable average precipitation only 30 rain gauge stations with records of more than 50 years were processed. It was found that there is no general statistical evidence of trend, because only two records showed a decreasing behavior; however, through the ratio (CO₁₅) between the average rainfall of the last 15 years and the long run (whose mode of 27 values is 0.975) shows a decrease in the annual rainfall.

Palavras-chave : homogeneity; persistence; trend; change in mean; seasonality; parametric tests; non parametric tests.