Some of the most critical impacts of climate change will probably occur due to changes in the extremes of the hydrological cycle (droughts and floods), yet the expected changes in future precipitation and its extremes are currently quite uncertain. Scenarios of future change are derived from simulations with global and regional climate models, and our confidence in scenarios of future precipitation extremes rests on our assessment of the reliability of those models.

We propose to evaluate these models by careful comparison of their simulations with observed variations in extreme precipitation events. Our comparisons will go far beyond simple comparisons of the statistics of simulated and observed events, but will in addition assess the linkages between atmospheric circulation variability (wind speeds and directions, stability, convergence and uplift), atmospheric humidity, and resulting precipitation extremes in both models and the real world. We will then extend the assessment to consider whether including changes in greenhouse gases (and other external climate influences) in the model simulations improves the agreement with changes detected in the observational data.

Project Duration: February 2007 - January 2009.

This project is funded by NERC - Grant Ref. NE/E002412/1 - through the Flood Risk for Extreme Events (FREE) NERC directed mode programme

The focus of this project is to perform new analyses of existing observational and model data. This will use the HadCM3 1000year control run data available and Met Office observation records both of which are available at the BADC. The output from this project will be in the form of an in depth comparison of simulated and observed events with additional assessment of the link between atmospheric circulation variability, humidity and precipitation events. No additional data output is expected to be archived for this project.

The metadata from this project will be stored at the BADC.

Documents currently available are:

• List of all stations selected for the analysis

HadCM3 data - http://badc.nerc.ac.uk/data/hadcm3/

Met Office MIDAS Land Surface Observations data - http://badc.nerc.ac.uk/data/ukmo-midas/

FREE Programme documentation:

• List of projects funded under the FREE programme.
• FREE Science Plan
• FREE Implementation Plan (January 2008)
• FREE Progress Report (May 2008)
• FREE Progress Report (Oct 2008)
• Data Inputs to FREE projects

This FREE project is headed by Dr Tim Osborn of the University of East Anglia (UEA), with co-investigators at the University of East Anglia.

General queries about these pages or browsing the data should be directed to the BADC support line.