A Flood Early Warning System Based on an Integrated Precipitation
Forecasting with Global Datasets for Adapting Weather Extremes in
Data-scarce Nile Delta
Abstract
This research is part of the ongoing research project − Climate change
Adaptation to ManagE the risks of extreme hydrologicaL and weather
events for food security in vulnerable west Nile delta (CAMEL). The
study area, West Nile Delta, is an important region in Egypt featuring
agricultural and industrial significance to the nation, whilst it faces
serious crises from the interaction of complex environmental problems
(e.g. flooding) which is exacerbated by climate change in the recent
decades. Under the pressure of growing population, food security has
become a national issue. In the latest decades, the region has
experienced more extreme weather events; the severe rainfall events have
resulted in flooding destroying massive crops and causing losses of
human life and livestock. The evolvement of society in this region has
made the people living in the flood-prone area – mostly farm labours −
relatively socio-economic vulnerable. This research hence focuses on the
urgent foregoing issue − disastrous pluvial flooding, which seeks to
mitigate the issue of crop production loss and human casualty caused by
climate change. Therefore, an adaption measure of an early warning
system for extreme events caused by heavy rainfall has become an urgent
demand. However, the scarcity of data (e.g. insufficiency in the
coverage of gauge stations and radar stations) has always been a main
obstacle to relevant measures in Egypt. The research hence seeks to cope
with such difficulty whilst to build an integrated flood early warning
system for Egypt. Based on the integration of Nowcasting method
(applying GPM and MPE satellite radar observation) and NWP method
(downscaling ECMWF data) as the substitution for the insufficient ground
observations, the integrated approach can take the advantages of both
data sources to perform better forecasting. However, GPM and MPE data,
compared with ground observation data, still reflects relative
disadvantages in spatial and temporal resolution in terms of Nowcasting
application. Besides, notwithstanding Nowcasting method can make up for
the spatial resolution of the NWP method, its mainstream − optical flow
approach based on the Lagrangian method − still lacks confidence in
dealing with local advection circumstance, as well as fast and drastic
formation and dissipation of precipitation. The research hence seeks to
improve Nowcasting, by applying a phase-based frame interpolation method
based on the Eulerian method, to refine the resolution of data to
improve the performance of Nowcasting. It features better performance in
precipitation change, strong precipitation divergence (i.e. light
contrast), and computational efficiency. The improved Nowcasting, for
further integrating with the NWP method, is being tested and proposed,
which will end up with a recommendation of policy and a novel tool –
real-time flood early warning system – so as to accommodate the
hydrological extremes towards climate change in Egypt.