Improving Hydrometeorological Forecasting Using High-Resolution X-Band Radars (HyFoX)

欧洲最近受到了一些持续时间较长的强降雨事件的影响。特别是山区和城市地区风险很高，因为暴雨会在陡峭的斜坡和不透水的地区引发毁灭性的洪水，造成严重破坏。预报这些洪水及其对洪水多发地区的影响仍然是水文气象预报人员面临的最大挑战之一。洪水预报的最大误差来源是降水估计的不确定性。国家气象局运行的时间分辨率为5分钟、空间分辨率为公里的C波段雷达的降水场被用作最新的降雨-径流模型的输入。新的偏振测量系统可以得到空间分辨率为250m的产品，但时间分辨率仍为5min。尽管在X波段范围内受降水衰减的影响较大，但事实证明，X波段雷达，特别是重叠的X波段雷达网络，是在时间(&lt；1分钟)和空间分辨率(&lt；250米)较高的地区为特别感兴趣的地区提供降水场的有效工具，作为全国雷达网的补充。在由Daniel Sempere-Torres教授指导的西班牙巴塞罗那阿普利卡达中心改进高分辨率X波段雷达水文气象预报的跨学科项目(UPC-CRAHI)中，将对三个不同的地区进行调查：德国汉堡北部的农村平坦地区；德国汉堡平坦的城市地区；以及包括西班牙巴塞罗那部分地区在内的贝索S河流域山区。所有三个集水区都由相应的国家气象局运营的C波段雷达网以及汉堡大学和UPC-CRAHI运营的X波段雷达覆盖。对于每个集水区，都有降雨-径流模型可用并在使用。这种独特的设置允许对高分辨率降水场对降雨-径流模型的影响进行详细的创新研究。水文模拟将通过将结果与水位和水流测量结果进行比较来验证。HyFoX所需的所有数据和模型都已准备就绪，但尚未合并。HyFoX的目的是展示高分辨率天气雷达观测对径流模拟的影响，并与不同环境中的极化C波段雷达进行比较和补充。这一结果将有助于更准确地识别洪灾风险增加的易发地区。这一点非常相关，特别是在城市地区，那里的洪水造成了数十亿美元的损失。对于哪些地区建立单一或组网的低成本、高分辨率天气雷达，作为对更大规模网络的补充，有利于改进洪水预报，加强预防和风险管理，可以提出建议。

Europe has recently been affected by a number of heavy and long lasting rainfall events. Especially mountainous and urban regions are at high risk, because heavy rainfall induces devastating floods at steep slopes and in impermeable areas leading to serious damage. Forecasting these floods and their impact on flood-prone regions is still one of the biggest challenges for hydrometeorological forecasters. The largest source of error in flood forecasting is uncertainty in precipitation estimation. Precipitation fields from C-band radars with temporal resolution in the order of 5 min and spatial resolution in the order of kilometres, as operated by national weather services, are used as input for state of the art rainfall-runoff models. Novel polarimetric systems can derive products with spatial resolution of 250 m, but still temporal resolution of 5 min. Despite higher influence of attenuation by precipitation in the X-band frequency range, X-band radars and in particular networks of overlapping X-band radars have been proven to be a valid tool to provide precipitation fields for areas of special interest in higher temporal (< 1 min) and higher spatial resolution (< 250 m) in complementation to nationwide radar networks. Within the interdisciplinary project Improving Hydrometeorological Forecasting Using High-Resolution X-Band Radars (HyFoX) under supervision of Prof. Daniel Sempere-Torres at the Centre de Recerca Aplicada in Hidrometeorologia (UPC-CRAHI), Barcelona, Spain, three different regions will be investigated: Rural flat area in the North of Hamburg, Germany; flat urban area of Hamburg, Germany, and mountainous urban area of the Besós River catchment including parts of Barcelona, Spain. All three catchments are covered by C-band radar networks operated by the corresponding national weather services and by X-band radars operated by the University of Hamburg and UPC-CRAHI. For each catchment rainfall-runoff models are available and in use. This unique set-up allows for a detailed innovative study of the impact of high-resolution precipitation fields on rainfall-runoff modelling. The hydrological simulations will be validated by comparing the results to water level and stream measurements. All data and models needed for HyFoX are available and ready to use, but have not been combined yet. The aim of HyFoX is to demonstrate the impact of high-resolution weather radar observations on runoff simulations in comparison to and in complementation of polarimetric C-band radars in different environments. The results will be valuable for identifying flood-prone areas of increased risk more precisely. This is highly relevant, especially in urban areas, where floods cause damages running into billions. Advice can be given for which areas setting up single or networks of low-cost, high-resolution weather radars as a complementation to larger scale networks is beneficial for improving flood forecasting and enhancing prevention and risk management.