Two Types of Statistical Climate Index Prediction

Climate variability is simply represented by teleconnection patterns such as the Arctic Oscillation (AO), Antarctic Oscillation (AAO), North Atlantic Oscillation (NAO), Pacific/North American Pattern (PNA), and Southern Oscillation (SO) with associated indices. Two approaches can be used to predict the indices: forward and backward methods. The forward method is commonly used to predict the index fluctuation f at time t with a given temporal increment t0. Using this method, it was found that the index (such as for NAO) has the Brownian fluctuations. On the base of the first passage time (FPT) concept, the backward method is to predict the typical time span (t0) needed to generate a fluctuation in the index of a given increment f. After the five climate indices (AO, AAO, NAO, PNA, SO) running through the past history, the FPT satisfies the inverse Gaussian distribution. FPT presents a new way to detect the temporal variability of the climate indices. Comparison between the forward and backward statistical climate index prediction is also presented.