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Met Office Perspective and Activities

Met Office Perspective and Activities. Ruth McDonald TEMPEST meeting 8 th February 2011. Validation of model winter BPF MSLP storm track wrt ERA40. HadCM3 A1B 11 members. CMIP3 AR4 multi-model ensemble. TQUMP perturbed physics ensemble.

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Met Office Perspective and Activities

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  1. Met Office Perspective and Activities Ruth McDonald TEMPEST meeting 8th February 2011

  2. Validation of model winter BPF MSLP storm track wrt ERA40 HadCM3 A1B 11 members CMIP3 AR4 multi-model ensemble TQUMP perturbed physics ensemble Errors in simulation of present day storms adds to uncertainty of future predictions units = hPa

  3. Uncertainty in future changes in storms: winter 2080s wrt 1961-1990 Cyclones (%) BPF MSLP Storm Track (hPa) TQUMP HadCM3 A1B 11 members CMIP3 Southward shift Intensification 4.3% fewer over NH

  4. RCM tracks and mean sea level pressure 18Z 0Z Shading is MSLP in hPa (colours are at 4 hPa intervals) Lines show tracks Features at time of MSLP fields are indicated by *s Tracking smaller scale features than in GCM 06Z 12Z

  5. Future changes in UK storms % change UK Storms Autumn 30y mean % changes All storms – no change % changes in cyclone track density DJF 2071-2099 minus 1961-1990 DJF 850 hPa wind speed > 17.5 ms-1 more Fewer UK storms no change in intensity % change RQUMP HadRM3 A1B perturbed physics 11 member ensemble

  6. Strength of UK storms in ERA40RCM • Example of strength distribution of UK storms in RCM • Can also use rainfall, gusts, mean sea level pressure and wind speed as storm intensity • AXA RACEWIN project will look at combined perils of wind and rainfall • Results from perturbed physics ensembles provide uncertainty estimates of distributions Max strength of storm (vorticity)

  7. Consultancy work:ABI The Financial Risks of Climate Change • AIR Worldwide Corp. and Met Office Report • UK Windstorms (also UK floods and China Typhoons) • Wanted changes in frequency and intensity of UK windstorms for High, Medium and Low • Literature review inconclusive for UK windstorms • Provided changes in latitude of storm track over UK from 17 HadCM3 A1B Transient QUMP ensemble and AR4 CMIP3 models • Input into CAT model

  8. Changes in winter UK BPF storm track – TQUMP and AR4 Change in latitude over UK (degrees) 3 conditions provided 1.45º southward shift Low prob shifts of: 4.4º north 7.28º south ABI report Fig 4 Climate Sensitivity (K)

  9. ABI The Financial Risks of Climate Change: UK windstorms Main Findings • Assuming a 1.45° southward shift in storm track across the UK: • The average annual insured wind losses in the UK could rise by 25% to £827 million. • The wind-related insured loss from winter season windstorms in the UK occurring once every 100 years could rise by 14% to £7.3 billion, and the loss occurring once every 200 years could rise by 12% to £9.7 billion. • Regional variations range from below 10% to 16% for the 100-year loss and below 10% to 17% for the 200-year loss. • The wind component of insurance premiums could increase by around 37% across the UK if a southward shift in storm tracks is assumed.

  10. Current work on storms • HadGEM2-CC high top v low top models • High top models are vertically extended and have improved representation of the stratosphere compared to low top model. Better able to simulate the stratosphere-troposphere interaction • Results show that future changes in the North Atlantic storm track are shifted south in some high top models compared to low top models • Theory is that the northward shift in storm tracks under climate change may be overestimated in low top models • HadCM3 has a southward shift in eastern North Atlantic • Aim is to test the theory by comparing changes in storms in HadGEM2 high (L60) and low top (L38) models • HadGEM2-ES and CMIP5 (maybe?) • Changes in storms in RCP4.5 and RCP8.5 experiments, compared to historical experiment. Use picontrol to assess natural variability. May just use simple diagnostics.

  11. Aims and links to other projects • Paper on drivers of changes in North Atlantic storms • Bringing together TQUMP, RQUMP, CMIP3, HadGEM2 and maybe CMIP5 results. • CS-RE • Joint perils of North Atlantic tropical cyclones and European windstorms – literature review recently completed • AXA RACEWIN • Use tracks from TQUMP and RQUMP • NERC TEMPEST • WP1 – related to HadGEM2 work • WP2 – related to TQUMP work • WP3 – related to HadGEM3 MORPH3 and CAPTIVATE projects. Also of interest for “seamless prediction”

  12. Questions and answers

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