Extending medium-range predictability of extreme hydrological events in Europe

Widespread flooding occurred across northwest Europe during the winter of 2013/14, resulting in large socioeconomic damages. In the historical record, extreme hydrological events have been connected with intense water vapour transport. Here we show that water vapour transport has higher medium-range predictability compared with precipitation in the winter 2013/14 forecasts from the European Centre for Medium-Range Weather Forecasts. Applying the concept of potential predictability, the transport is found to extend the forecast horizon by 3 days in some European regions. Our results suggest that the breakdown in precipitation predictability is due to uncertainty in the horizontal mass convergence location, an essential mechanism for precipitation generation. Furthermore, the predictability increases with larger spatial averages. Given the strong association between precipitation and water vapour transport, especially for extreme events, we conclude that the higher transport predictability could be used as a model diagnostic to increase preparedness for extreme hydrological events.

[1]  B. Soden,et al.  Robust Responses of the Hydrological Cycle to Global Warming , 2006 .

[2]  B. Soden,et al.  Atmospheric Warming and the Amplification of Precipitation Extremes , 2008, Science.

[3]  J. Thielen,et al.  The European Flood Alert System – Part 1: Concept and development , 2008 .

[4]  F. Pappenberger,et al.  Sensitivity of model climate to sampling configurations and the impact on the Extreme Forecast Index , 2015 .

[5]  Arun Kumar,et al.  Is There a Relationship between Potential and Actual Skill , 2014 .

[6]  David M. Schultz,et al.  The Use of Moisture Flux Convergence in Forecasting Convective Initiation: Historical and Operational Perspectives , 2005 .

[7]  F. Martin Ralph,et al.  Meteorological Characteristics and Overland Precipitation Impacts of Atmospheric Rivers Affecting the West Coast of North America Based on Eight Years of SSM/I Satellite Observations , 2008 .

[8]  F. Pappenberger,et al.  Seasonal forecasts of droughts in African basins using the Standardized Precipitation Index , 2013 .

[9]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[10]  Michael D. Dettinger,et al.  Observed Impacts of Duration and Seasonality of Atmospheric-River Landfalls on Soil Moisture and Runoff in Coastal Northern California , 2013 .

[11]  F. Pappenberger,et al.  The impact of weather forecast improvements on large scale hydrology: analysing a decade of forecasts of the European Flood Alert System , 2010 .

[12]  Edmund C. Penning-Rowsell,et al.  A realistic assessment of fluvial and coastal flood risk in England and Wales , 2015 .

[13]  M. Dettinger,et al.  Storms, floods, and the science of atmospheric rivers , 2011 .

[14]  P. O'Gorman,et al.  The physical basis for increases in precipitation extremes in simulations of 21st-century climate change , 2009, Proceedings of the National Academy of Sciences.

[15]  G. Villarini,et al.  The nexus between atmospheric rivers and extreme precipitation across Europe , 2013 .

[16]  Jutta Thielen,et al.  The european flood alert system EFAS - Part 2: statistical skill assessment of probabilistic and deterministic operational forecasts. , 2008 .

[17]  Stéphane Hallegatte,et al.  A Cost Effective Solution to Reduce Disaster Losses in Developing Countries: Hydro-Meteorological Services, Early Warning, and Evacuation , 2012 .

[18]  E. Wood,et al.  Assessing the idealized predictability of precipitation and temperature in the NCEP Climate Forecast System , 2006 .

[19]  Tim N. Palmer,et al.  Ensemble forecasting , 2008, J. Comput. Phys..

[20]  H. Wheater.  Flood hazard and management: a UK perspective , 2006, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[21]  Eric F. Wood,et al.  Winter floods in Britain are connected to atmospheric rivers , 2011 .

[22]  Eric F. Wood,et al.  The detection of atmospheric rivers in atmospheric reanalyses and their links to British winter floods and the large‐scale climatic circulation , 2012 .

[23]  Martin Leutbecher,et al.  Scale‐dependent verification of ensemble forecasts , 2008 .