Interannual to Decadal Variability in Hydroclimatic Data: Analyses and Implications to Water Management

Analysis of decadal variability in climatic data provides better understanding of climate dynamic system. But, the land surface runoff could exhibit a different signature since it is influenced by the variability on both precipitation and temperature. Understanding the decadal variability is also critical for water infrastructure design and long-term planning. We apply Singular Spectrum Analysis (SSA), a data-driven spectrum analysis tool, on precipitation, temperature and streamflow from HCDN watersheds to identify the dominant frequencies and to estimate the variability associated with them. Hypothesis test against an AR(1) process is carried out via Monte Carolo SSA, which detects an oscillation at 90% confidence. Initial results show that hydroclimatic data reveals inter-annual to decadal oscillation. In order to find out whether streamflow and climatic data reveal significant correlation at a certain frequency, cross spectrum analysis between streamflow and precipitation will be employed. Implications of these analyses in the context of decadal climate predictions and their importance to water management will also be discussed.