INcreasing the VAlue of Campaign Observations through Data Assimilation to advance convective predictability

Forecasting intense summer-time convection – especially in complex terrain - remains a challenge, even for high-resolution regional numerical weather prediction (NWP) models. The predictability horizon is limited to a few hours, even for high-resolution, convection-permitting ensemble prediction systems. High-resolution observations, e.g. Doppler wind lidars, the network of global navigation satellite receivers (GNSS) or novel water vapor profilers (DIAL), offer a new potential to enhance the predictability and our understanding of mesoscale convective processes.

This is, what INVACODA aims for: We want to explore how high-resolution observations could enhance predictability, either through their assimilation in operational systems or through the process of evaluation and model development. For that, INVACODA will evaluate DWD’s operational analyses and ensemble forecasts with observations from campaigns targeting summer-time convection, and conduct high-resolution data influence and impact experiments. The results shall be used to improve the observational strategy for future campaigns. In parallel, detailed process and modelling studies aim to improve our understanding of convective initiation and intensification.

INVACODA is embedded in the Italia-Deutschland Science-4-Services network (IDEA S4S) and collaborates closely with DWD, the University of Bologna and the Institute of Atmospheric Sciences and Climate at the National Research Council of Italy. Both countries have regions with complex terrain that are regularly affected by heavy convective precipitation and flooding. Therefore, our results aim to guide future extensions of the observational network of both countries and to improve forecasting of convection over complex terrain.

Two PhD projects within the project assess the following research questions:

(1) Which processes and on which spatial and temporal scales determine the initiation and intensification of convective events, and how well are they represented in the convection-permitting ensemble prediction system of DWD?

(2) Can high-resolution observations of the dynamic and thermodynamic structure of the lower troposphere in complex terrain reduce forecast uncertainty and improve ensemble forecasts of high-impact convective events, and if so, which observations are most beneficial?