Analysis of Long-Term Changes in Annual and Seasonal Precipitation in Chile and Related Large-Scale Atmospheric Circulation Patterns

摘要

The study of empirical teleconnections between annual and seasonal precipitation anomalies and different climate indices i.e. SOI, PDO, MEI, AAO, ONI, TWI, N3.4, TNI, and MJO, is an important approach to describe and analyze spatial and temporal precipitation variability. The objective of this study was to describe and analyze the main features of interannual and seasonal precipitation variability along Chile, and the influence of different ocean-atmospheric oscillations on secular long-term patterns. An exhaustive analysis through Empirical Orthogonal Functions (EOF) allowed determining the significant modes of annual and seasonal precipitation, and the main spatial patterns associated to them. Discrete Fourier Transform (DFT), the Singular Spectrum Analysis (SSA), and the Multichannel Singular Spectrum Analysis (M-SSA) were additionally used to determine the main frequencies and oscillatory components associated with leading climatic modes and precipitation patterns. The results agreed with those obtained by other authors and also when using different datasets. Despite advances on detailed annual and seasonal analysis that were carried out here, more detailed country-based studies are still required to develop a detailed understanding about climatic patterns along a country that is geographically very difficult to investigate.