Developing probabilistic representations of climatic influences on hydrological response using a coupled hydrological—atmospheric model

Abstract

An innovative way of characterizing regional climatic variability is to quantify a dynamic probability distribution of hydrological response conditioned upon a specified hydroclimatic event such as the El Niño Southern Oscillation (ENSO). The hydrological response probability distribution contains the probability of all possible hydrological responses to the specified hydroclimatic event limited only by the physics of the hydroclimatic system. A case study using three characterizations of a La Niña event (the cold phase of ENSO) is presented to show the results of investigations into the influence of different elements of the hydrological response probability distributions derived from Monte Carlo simulations with a coupled hydrological—atmospheric model. The response probability distributions obtained from the three sets of simulations are compared to each other as well as historical data, and differences are discussed. Implications of each approach in terms of seasonal forecasting for water resources planning are discussed.