Met Office Presentation September 2013
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Presentation on Climate Change in Wales by Professor Julia Slingo Met Office Chief Scientist
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Met Office Presentation September 2013
- 1. Climate change and Wales Professor Julia Slingo, Met Office Chief Scientist © Crown copyright Met Office
- 2. Changing Research Agenda • Increasing vulnerability to hazardous weather and climate extremes demands greater preparedness and resilience now. • Commitment to a certain level of climate change in the next 20-30 years means that adaptation in the future is unavoidable. • Mitigation policies require a greater understanding of Earth System processes and feedbacks, and of our commitments to long-term or irreversible change. © Crown copyright Met Office
- 3. Understanding our present climate and extremes © Crown copyright Met Office
- 4. Why was this Spring so cold? 2013 closely resembles the state of the climate system in 1962 © Crown copyright Met Office
- 5. Global rainfall anomalies (left panel) and surface air temperature anomalies (right panel) for March 1962 against the climatology for 1981-2010. SST anomalies for March 2013 (top) and March1962 (bottom) relative to 1981-2010
- 6. Sudden Stratospheric Warming in January 2013
- 8. Anomalies in monthly Arctic sea ice extent from 1979
- 9. Extreme weather November/December 2010 December 2010: Record minimum monthly average temperature for Wales = -3.8 degC Record minimum Nov temperature: -18.0 C at Llysdinam (Powys) on 28 November 2010, lowest November min. temperature in Wales on record
- 10. Extreme weather November/December 2010 Return time of temperatures for December in 20002009 decade Return time of temperatures for December in 19601969 decade Dec 2010 CET The odds of the cold December 2010 temperatures have halved as a result of human‐induced climate change
- 11. Predicting the Future © Crown copyright Met Office
- 12. Fundamentals of weather and climate modelling Forecast models are huge computer codes based on fundamental mathematical equations of motion, mass continuity, moist thermodynamics and radiative transfer These govern: Flow of air and water - winds in the atmosphere, currents in the ocean. Exchange of heat between the atmosphere and the earth’s surface Release of latent heat by condensation during the formation of clouds and raindrops Absorption of solar radiation and emission of thermal (infra-red) radiation NB: Solar output, Earth’s rotation (and atmospheric © Crown copyright Met Office composition) are the only imposed constraints.
- 13. Fundamentals of weather and climate modelling Represent the earth by a grid of squares, typically of length 100 km or smaller. Atmosphere and oceans are divided into vertical slices of varying depths. 3-dimensional picture of the state of the atmosphere and oceans. Integrate equations of motion and thermodynamics forward in time. © Crown copyright Met Office Conserve heat, moisture, salinity and momentum
- 14. Moving from uncertainty to probabilities/likelihoods UKCP09 Single projection Summer Rainfall 2080’s UKCIP02 Very unlikely to be less than (10%) Central estimate (50%) Very unlikely to be more than (90%)
- 15. - Hotter, drier summers?? Impacts - Milder wetter winters - Reduction in snowfall and frost - Increased frequency of intense rainfall events -Decrease groundwater levels -Increased flooding of low-lying coastal areas Sea level change – central probability estimate. Medium emission scenario 22 cm by 2050 Sea level rise (relative 1990) [cm] 60 High Medium 50 Low 40 30 20 10 Cardiff 0 © Crown copyright Met Office 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2095 % change in flood frequency of 2-year return period flow
- 16. UKCP09: The first step on a long road... Significant step forwards: • First to quantify uncertainties and provide probability distribution functions • First to include feedbacks and uncertainties from carbon cycle But…… • No wind or snow variables, only limited information on extremes – but more could be extracted from the regional climate model ensembles • No account of the current state of the climate system © Crown copyright Met Office © Crown copyright Met Office
- 17. 10-year Vision: Integrated weather and climate prediction for estimating hazards and risks N x Global predictions at ~20km with lead times of days to years: <N x Regional predictions at ~1km: Probability of local hazard: Synoptic drivers Local meteorology Impacts © Crown copyright Met Office
- 18. 1.5km resolution climate model Resolution of Welsh terrain Best longterm climate models, UKCP09 Current global weather forecasting State-of-art seasonal model configuration Current UK weather forecasting + groundbreaking climate work
- 19. West Wales flooding: 8-9 June 2012 1.5 km forecast model 12 UTC analysis 1.5 km L70 From RADAR
- 20. 1.5km resolution climate model Ground-breaking science • Same formulation as new 1.5km weather forecast model, run operationally since last year • Spans southern England and Wales at 1.5km resolution • Driven by 12km regional climate model at boundaries (in turn driven by reanalysis data) • Explicitly represents convection without need for parameterisation scheme • Completed 20 years: 1989-2008 • Just started climate change experiments using global 60km model output for boundary forcing, enabling study of climate change and extremes
- 21. Environmental Prediction at Regional and Local Scales • Established models exist for most components • Modeling scales are converging
- 22. How resilient are our assets to future change?
- 23. What future extremes should we prepare for?
- 24. How can science inform future investments?
- 25. Climate services: A revolution in the application of climate science • From mitigation to mitigation and adaptation • Climate change to climate change and climate variability • Global, century-scale scenarios to regional predictions, days to decades ahead • Global climate to characteristics of hazardous weather and climate extremes • From few to many customers – public, governments, business and industry • Operational delivery – from IPCC Assessment Reports to regularly updated monitoring, forecasts, products and services © Crown copyright Met Office
- 26. © Crown copyright Met Office Discussion
- 27. Opportunities for partnership Extreme Weather Initiative Wales • Performance of 1.5km model to represent extreme rainfall characteristics in South Wales catchments • 20 year hourly rainfall climatology, including variability and extremes, and comparison with observations • Grid-scale and catchment-scale analysis • Comparison with 12km driving model to assess benefits of very high resolution modelling for Wales • Climate change experiments at 1.5km over South Wales • Application of HPC Wales capability • Additional ensemble member experiments, to complement timeslice runs at Met Office, to allow climate change signal to be extracted from noise due to climate variability • Analysis of projected changes in rainfall, limited to those metrics where 1.5km model shown to be skilful for present day • Provision of guidance on implications for climate change advice and flood risk planning in Wales
Notes de l'éditeur
- Comparing climate model simulations with and without human factors shows that the cold UK winter of 2010/2011 has become about half as likely as a result of human influence on climate, illustrating that some extreme events are becoming less likely due to climate changeReturn times of temperatures for November in the 1960–1969 decade (blue curve) and the 2000–2009 decade (red curve). The observed value for the warm November 2011 of 9.6°C is shown on both curves as a solid, larger circle, with a return period in 1960–1969 of 1250 years and in 2000–2009 of 20 years. (b) Return times of temperatures for December in the 1960–1969 decade (blue curve) and the 2000–2009 decade (red curve). The observed value for the cold December 2010 of –0.7°C is again shown as a solid, large circle, with a return period in 1960–1969 of 139 years and in 2000–2009 of 278 years.Although the occurrence of a cold December in the 2000s has decreased from the 1960s, the difference in temperature of the 100-yr event is 0.87°C. The cold December of 2010, which is the second coldest December and coldest since 1890, has a monthly mean temperature of –0.7°C, which has a return period of 139 years in the 1960s and a return period of 278 in the 2000s. Therefore, a cold December of –0.7°C is half as likely to occur in the 2000s when compared to the 1960s.