Although tropical cyclone track forecast errors have substantially decreased in recent decades,there are still cases each season with large uncertainties in the forecasts and/or very large track errors.As such cases a...Although tropical cyclone track forecast errors have substantially decreased in recent decades,there are still cases each season with large uncertainties in the forecasts and/or very large track errors.As such cases are challenging for forecasters,it is important to understand the mechanisms behind the low predictability.For this purpose the research community has developed a number of tools.These tools include ensemble and adjoint sensitivity models,ensemble perturbation experiments and nudging experiments.In this report we discuss definitions of difficult cases for tropical cyclone track forecasts,diagnostic techniques to understand sources of errors,lessons learnt in recent years and recommendations for future work.展开更多
The quality control,validation and verification of the European Flood Alert System(EFAS)are described.EFAS is designed as a flood early warning system at pan-European scale,to complement national systems and provide f...The quality control,validation and verification of the European Flood Alert System(EFAS)are described.EFAS is designed as a flood early warning system at pan-European scale,to complement national systems and provide flood warnings more than 2 days before a flood.On average 2030 alerts per year are sent out to the EFAS partner network which consists of 24 National hydrological authorities responsible for transnational river basins.Quality control of the system includes the evaluation of the hits,misses and false alarms,showing that EFAS has more than 50%of the time hits.Furthermore,the skills of both the meteorological as well as the hydrological forecasts are evaluated,and are included here for a 10-year period.Next,end-user needs and feedback are systematically analysed.Suggested improvements,such as real-time river discharge updating,are currently implemented.展开更多
基金supported by the Research Grants Council(RGC)of Hong Kong,General Research Fund(CityU11332816)supported by the Chief of Naval Research through the NRL Base Program PE 0601153N and the Office of Naval Research PE 0601153NComputational resources for Doyle’s and Komaromi’s research were supported by a grant of High Performance Computing time from the Department of Defense Major Shared Resource Centers,Stennis Space Center,MS.
文摘Although tropical cyclone track forecast errors have substantially decreased in recent decades,there are still cases each season with large uncertainties in the forecasts and/or very large track errors.As such cases are challenging for forecasters,it is important to understand the mechanisms behind the low predictability.For this purpose the research community has developed a number of tools.These tools include ensemble and adjoint sensitivity models,ensemble perturbation experiments and nudging experiments.In this report we discuss definitions of difficult cases for tropical cyclone track forecasts,diagnostic techniques to understand sources of errors,lessons learnt in recent years and recommendations for future work.
文摘The quality control,validation and verification of the European Flood Alert System(EFAS)are described.EFAS is designed as a flood early warning system at pan-European scale,to complement national systems and provide flood warnings more than 2 days before a flood.On average 2030 alerts per year are sent out to the EFAS partner network which consists of 24 National hydrological authorities responsible for transnational river basins.Quality control of the system includes the evaluation of the hits,misses and false alarms,showing that EFAS has more than 50%of the time hits.Furthermore,the skills of both the meteorological as well as the hydrological forecasts are evaluated,and are included here for a 10-year period.Next,end-user needs and feedback are systematically analysed.Suggested improvements,such as real-time river discharge updating,are currently implemented.
