#15 Hydrologic Metrics

Abstract

Annual mean, inter- and intra-annual variability of streamflow and floods are typical hydrological indicators used to evaluate and diagnose hydrological model simulations. Each is dominated by different hydrological processes. By analyzing observed runoff data from 250 natural small watersheds throughout the United States, close functional relationships are revealed between these indicators and climate aridity index, implying emergent linkages among these indicators themselves. Based on a mathematical framework, these emergent linkages appear to arise from the interconnections between different hydrological processes. We propose that these functional relationships and emergent linkages can be potentially used as new hydrologic metrics to inform model performance, shed light on causes of model biases, and reveal other implications of hydrological modeling in the larger context of Earth System Model. We will illustrate these potential new metrics on the global runoff simulations by the ACME-land component. Additionally current limitations and future directions will be discussed.