Print Email Facebook Twitter Intra-annual rainfall variability control on interannual variability of catchment water balance: A stochastic analysis Title Intra-annual rainfall variability control on interannual variability of catchment water balance: A stochastic analysis Author Zanardo, S. Harman, C.J. Troch, P.A. Rao, P.S.C. Sivapalan, M. Faculty Civil Engineering and Geosciences Department Water Management Date 2012-01-18 Abstract We evaluate the extent to which within-year rainfall variability controls interannual variability of catchment water balance. To this end, we analytically derive the probability density function of the annual Budyko evaporation index, B (i.e., the ratio of annual actual evapotranspiration to annual precipitation), by accounting for the stochastic nature of intra-annual rainfall fluctuation and neglecting all other sources of variability. We apply our analytical model to 424 catchments located in different climatic regions across the conterminous United States to perform this assessment. In general, we found that the model is capable of explaining mean B but is less accurate in predicting its coefficient of variation. Nonetheless, in a significant number of catchments the model can provide adequate predictions of the probability density function of B. Clear geographic patterns can be distinguished in the residuals between observed and predicted statistics of B. Interannual variability is thus not always associated with random intra-annual rainfall fluctuations. In some regions, other controls, such as seasonality and vegetation adaptations, are possibly more important. A sensitivity analysis of model parameters helped characterize the dominant controls on the distribution of B in terms of three dimensionless ratios that include climatic and soil characteristics. This study represents the first step in a diagnostic, data-driven analysis of the climatic controls on the interannual variability of catchment water balance. Subject catchmentclimateecohydrologymodeling To reference this document use: http://resolver.tudelft.nl/uuid:5d7a4b34-1bb4-4248-b4da-a75603a94eb4 Publisher American Geophysical Union ISSN 0043-1397 Source Water Resources Research, 48 (6), 2012 Part of collection Institutional Repository Document type journal article Rights (c) 2012 American Geophysical Union Files PDF Sivapalan_2012.pdf 1.11 MB Close viewer /islandora/object/uuid:5d7a4b34-1bb4-4248-b4da-a75603a94eb4/datastream/OBJ/view