AN INTERANNUAL CLIMATOLOGICAL ARIDITY SERIES FOR THE SIERRA-DE-LA-LAGUNA, BCS MEXICO

The Sierra de La Laguna is a group of mountains in the south of the Ba ja California Peninsula that, because of their height, show marked cli matic differences. The life forms there are different from the rest of the Peninsula and the area is the site of many ecological studies. Th e objective of this paper is to construct a regional climatic series t hat can be useful for detecting annual dry and wet periods. An aridity index is calculated according to Martonne, using precipitation and te mperature data from nine meteorological stations in the middle and low er ranges of the Sierra. When an auto-correction and Fourier analysis of the resultant series is made, a tendency to less aridity is observe d with a fundamental frequency of 24 years, which approximates conform ance to the double cycle of sunspots.