Analysis of relations between δ18O the ice core of Nevado Illimani (Bolivia) with the precipitations in the tropical region of South America (1929-1998)

This paper examines the space-temporal relations between a time serie oxygen stable isotopes ratio (δ 18 O), obtained from an ice core in Nevado Illimani (Bolivia), and the precipitation serie in South America Tropical, the period 19291998. For the purpose of upgrade the statistical representativity of the reconstruction of the preterit precipitation in a tropical region, using the δ 18 O. We used δ 18 O data from the upper 50 m of this core and 37 precipitation series was collected in Brazil and Bolivia. Additionally, the time series of precipitations were calculated by subtracting of the mean monthly of original series, resulting in anomalies. The dependency analysis has four stages: elaboration of scatter diagrams, identification of mathematical regression equations, error measurement and measurement of the correlation coefficient. By comparing the δ 18 O with precipitation was identified that the correlation indices larger are about | 0.2 |, so it is impossible makes the paleoclimatic reconstruction from a linear regression used the δ 18 O. However, relations between the variables show that the δ 18 O maximum (minimum) are related to dry (rain above the mean) in Amazon and Central Brazil and rain above the mean (dry) in northeast Brazil, Minas Gerais, Amazonas and Roraima.