Quantitative Precipitation Estimation (QPE) by exploiting the potential of advanced radar observations and data assimilation

该项目的总体目标是通过在适当的时空分辨率下提供定量的地面降水估算（QPE）来改进中尺度的水文建模。目标比例尺为1000 km²，分辨率为1000 m / 1小时。为此，我们将研究并结合两种QPE方法：第一种是结合对流允许的大气建模和使用先进数据同化技术（变分技术、集合卡尔曼滤波器及其组合）的新观测。主要观测数据包括c波段雷达反射率、径向速度和极化、微雨雷达（MRR）反射率、雨率和雨滴大小分布（DSD）的垂直剖面以及畸变仪DSD。特别是，我们正在探索MRR观测和c波段雷达极化测量的价值。高分辨率数据分析充分利用了雷达数据的三维信息内容，是QPE的一个很有前途的工具。该模型产生的物理上一致的三维热力学场允许对观测数据进行质量控制，并在未观测位置充当动态物理插补器。第二种方法是基于先进观测的QPE，包括雷达反射率和偏振测量的协同作用，以及MRR，畸变仪和雨量测量，使用先进的地质统计学插值和模拟技术。我们还将探索如何产生基于模型和基于观测的QPE领域的混合组合。试验区是卢森堡的Alzette集水区（1090平方公里），研究单位的重点区域Attert（288平方公里）嵌套在其中。

The overarching objective of this project is to improve hydrological modeling on the mesoscale by providing quantitative ground precipitation estimates (QPE) in an adequate spatiotemporal resolution. Target scale is 1.000 km² in 1000 m / 1 hour resolution. To this end, we will investigate and combine two QPE approaches: The first is to combine convection-permitting atmospheric modeling and new observations using advanced data assimilation techniques (Variational techniques, Ensemble Kalman Filters and combinations thereof). Key observations are C-band radar reflectivity, radial velocity, and polarization, Micro Rain Radar (MRR) vertical profiles of reflectivity, rain rate, and drop size distribution (DSD), as well as distrometer DSD. Particularly, we are exploring the value of MRR observations and of C-Band radar polarimetric measurements. High-resolution DA is a promising tool for QPE as it takes full advantage of the 3D information content of radar data. The physically consistent 3D thermodynamic field produced by the model allows quality control of observational data and acts as a dynamic-physical interpolator at unobserved locations. The second approach is QPE based on advanced observations, consisting of a synergy of radar reflectivity and polarization measurements, as well as MRR, distrometer, and raingauge observations using advanced geostatistical interpolation and simulation techniques. We will also explore ways to produce hybrid combinations of modeland observation-based QPE fields. Test area is the Alzette catchment in Luxembourg (1090 km²), with the focus area of the research unit, Attert (288 km²), nested within.