From Recent Significant Precipitation in China to a Glocal Hydrometeorological Solution for Flood Risk Prediction

Abstract:

Due to an earlier-than-usual onset of South China Sea summer monsoon and a more northward location retained by the western Pacific Subtropical High in 2020, the Mei-yu front occurred earlier than most of the years. The prolonged Meiyu-Baiu system with anomalous precipitation has swollen many rivers and lakes, caused flash flooding, urban flooding and landslides, and consistently wreaked havoc across large swathes of China, particularly in Yangtze river basin. Significant precipitation and flooding anomalies have already been seen in magnitude and extension by now for this year, which have been exerting much higher pressure to emergency response in flood control and mitigation than in other years, even though a rainy season with multiple on-going serious flood events in different provinces is not very uncommon in China. Timely and accurate classification of flood risks of today and a few days into the near future at both large and local scales are thus highly desirable for decision makers. Instead of digging into the causations of the uniqueness of this year’s extreme precipitation-flooding situation, which certainly warrants exploration in-depth, we here provide a view toward a more general hydrometeorological solution to this “annual” nationwide problem. We hope to draw a close attention of the hydrology-meteorology community to re-think of what more can be done for better prepared for and responding to such catastrophic flooding events in the future, in particular from a hydrometeorological modeler’s perspective, given the high possibility of more frequent and extreme precipitation events under a continuously warming climate. A Glocal (global & local) Hydrometeorological Solution to Floods (GHS-F) is considered to be critical for better preparedness, mitigation, and management of significant precipitation-caused different types of flooding which happen extensively almost every year in many countries such as China, India and USA. Such a GHS-F is necessary from both scientific and operational perspectives with the strength in providing spatially consistent flood definition and spatially distributed flood risk classification considering the heterogeneity in vulnerability and resilience across the entire domain.