Characteristics of Atmospheric Circulation Anomalous Patterns Inducing Torrential Rain and Floods in the Danube River Basin

Abstract

Global warming has enhanced the water-holding capacity of the atmosphere and increased the intensity and probability of torrential rain, posing a huge threat to the sustainable development of the regional economy and society. The economic losses caused by floods in the Danube River Basin in Europe are increasing, which further highlights the harm of floods to the human economy and society. Floods are often caused by persistent torrential rains. The occurrence of large-scale torrential rain and floods is closely related to the occurrence and development of atmospheric circulation characteristics in the early stage. The possible mechanism of torrential rain and floods in this region can be further revealed by clarifying the anomalous characteristics of atmospheric circulation in the early stage of the flood. In this study, the anomalous signal patterns of atmospheric circulation were identified, and the influence process of the anomalous signals on the Danube floods in the early stage was revealed, by analyzing the evolution process of global geopotential height anomaly in the early stage of floods in August over Danube River Basin. The results showed that the Arctic Oscillation (AO), North Atlantic Oscillation (NAO) and North Atlantic-Northern Europe blocking high can all be used as abnormal signals to induce torrential rain and flood events in the Danube River Basin. The AO positive phase, NAO positive phase, and the North Atlantic-Northern Europe blocking high were more intense, and the flood intensity in the Danube River Basin are stronger. The results of this study have significant implications for flood forecasting and the design of flood control measures.