Does the Danube exist? Versions of reality given by various regional climate models and climatological data sets

摘要: [1] We present an auditing (intercomparison and verification) of several regional climate models (RCMs) nested into the same run atmospheric global circulation model (AGCM) regarding their representation statistical properties hydrological balance Danube river basin for 1961–1990. We also consider data sets produced by driving AGCM, European Centre Medium-Range Weather Forecasts (ECMWF) National Centers Environmental Prediction (NCEP)–National Center Atmospheric Research (NCAR) reanalyses. The is computed integrating precipitation evaporation fields over area interest. Large discrepancies exist among RCMs monthly climatology as well mean variability annual balances, only few are consistent with observed discharge values at its Delta, even if AGCM provides itself excellent estimate. find consistently that, a given model, increases in resolution do not alter net water balance, while speeding up cycle through enhancement both amount. Since considered approach relies on mass conservation principle bypasses details air-land interface modeling, we propose that components still face difficulties representing relatively large scale. Their reliability smaller basins may be more problematic. Moreover, since some estimates obtained runoff agree those via evaporation, deficiencies land apparent. greatly overperforms NCEP-NCAR ECMWF 40-year (ERA-40) reanalyses, which result to largely inadequate hydrology basin, reconstruction long-term averages seasonal cycle. reanalyses cannot any sense used verification. suggest these results should carefully perspective assessing ability simulate future changes.