Identification of a Function to Fit the Flow Duration Curve and Parameterization of a Semi-Arid Region in North China

The discharge process has undergone major changes in many river basins throughout the world as a result of simultaneous influences global climate change and human activity. Flow duration curves (FDCs) are crucial indicators basins’ hydrological processes. However, it is challenging to compare FDCs quantitative way. This study will identify best function with which fit flow curve semi-arid region North China, so quantify FDC, parameterize FDC order describe ungauged basins. In this work, six small- medium-sized catchments China selected area, three functions, i.e., log normal, generalized Pareto H2018 were chosen at nineteen stations. relationship between parameters basin characteristics, such climatic factors geographical features, analyzed. A regression formula was established, its spatial temporal distributions examined. Based on evaluation four indicators, Nash–Sutcliffe efficiency, root mean square relative error, logarithmic Nash efficiency coefficient determination, results demonstrate that can match best. Through annual runoff, precipitation, precipitation summer, potential evapotranspiration, catchment elevation, length main channel maximum frequency, a, b, k be formulated. constructed obtain regional satisfactory performance, provides reference for validation remote-sensing-based runoff data regions.