Weather radar information processing and real-time flood forecasting
This thesis describes research into remotely sensed weather radar information systems and specifically addresses three problems; 1) Weather radar data processing; 2) Real-time flood forecasting models and 3) Computer system design for the realisation of the real-time flood forecasting system using radar data. Quantitative rainfall measurements utilising weather radar is of high temporal and spatial resolution when compared with traditional rainfall measurements. Analysis was carried out to assessth e type of radar datap roductsr equired for operational use in flood forecastings ystem. This includes issues of data processing such as quantisation, temporal sampling and spatial sampling. The influence of the data process on hydrological applications is also addressed. Theoretical analysis was carried out to probe the characteristics of Transfer Function Models and robust flood forecasting modelling procedure is proposed. The proposed model is always stable and physical realisable and is described as PRTF (Physical Realisable Transfer Function model). Algorithms and software for the identification of PRTF are presented. It was found that such a model is easy to identify and more importantly it can be updated robustly in real time. By changing the impulse response of the PRTF, it has been found that significant improvements can be observed in river flow simulation. A RST (Rainfall S eparation Tank) model was developed and incorporated into the PRTF model. The adaptivity of the PRTF also has the potential to make use of high spatial resolution radar rainfall data and could be further incorporated into an Expert System suitable for real-time application. Finally, the thesis includes the development of the WRIP system (Weather Radar Information Processor). Such a system can process weather radar information and use it for the real-time flood forecasting. The system design consists of database design, user interface design and program design. An object-oriented computing concept is used in the program design. The final system is currently in test operation within the N. R. A Wessex Region, including the man machine interface (MMI) incorporating a portable computer based data acquisition and display system known by the acronym `STORM' (System To Obtain Radar Rainfall Measurements).