Streamflow elasticity vs aridity – a large sample elasticity study

Hydrologists are requested to quantify the response of catchments with respect to climatic variability or climatic changes: for this, they need to be able to assess the climate elasticity of streamflow. Here, we present a large sample study, based on 4122 catchments from four continents, investigating to which extent the climate elasticity of streamflow depends on aridity, i.e. the ratio of the long-term average values of potential evaporation to precipitation. After examining the example of the “Budyko-type” water balance formulas – which embed the dependency between elasticity and aridity – we use catchment data to verify empirically the existence of this link and we discuss the possibilities to impose the dependency to aridity in elasticity in order to obtain more physically-consistent elasticity coefficients.