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Regional Climate, Extremes, and Impacts

Regional Climate, Extremes, and Impacts. Regional temperature trends, and the 2012 MAM warm anomaly over the eastern U.S. and Regional impacts of El Ni ñ o. presented by Andrew Wittenberg NOAA/GFDL. What do the new CMIP5 models say about the causes of regional surface temperature trends?.

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Regional Climate, Extremes, and Impacts

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  1. Regional Climate, Extremes, and Impacts Regional temperature trends, and the 2012 MAM warm anomaly over the eastern U.S. and Regional impacts of El Niño presented by Andrew Wittenberg NOAA/GFDL

  2. What do the new CMIP5 models say about the causes of regional surface temperature trends?

  3. Global mean surface temperatures: Trends-to-2010 90% of individual model realizations CMIP5 all-forcing Obs °C / century CMIP5 natural 1901-2010 trend 1981-2010 trend Knutson, Zeng, and Wittenberg (J. Climate, 2013)

  4. Alaska Rest of U.S. Southeast U.S. U.S. surface temperatures: Trends-to-2010 °C / century °C / century Knutson, Zeng, and Wittenberg (J. Climate, 2013)

  5. 1981-2010 1981-2010 °C / century warming > sim warming ~ sim warming < sim undetected cooling < sim cooling ~ sim cooling > sim Regional surface temperature trends: 5°x5° boxes 1901-2010 Observed °C / century CMIP5 all-forcing ensemble mean warming > sim warming ~ sim warming < sim Trend assessment undetected cooling < sim cooling ~ sim cooling > sim Knutson, Zeng, and Wittenberg (J. Climate, 2013)

  6. Record heat in MAM CMIP5 trend assessment foreastern U.S. in MAM All-forcing °C / century Unforced obs forced 2012 warm anomalies over the eastern U.S. Knutson, Zeng, and Wittenberg (BAMS, 2013 subm.) Areas where available 1850-2012 HADCRUT4 obs show record MAM surface temperatures in 2012. MAM eastern U.S. surface temperatures show: - long-term trend of nearly 1°C / century - warming trend exceeding CMIP5 unforced variability - trend consistent with CMIP5 forced runs Ensemble-mean CMIP5 forced response is ~35% the size of the 2012 MAM warm anomaly. Internal variability is substantial.

  7. Regional extremes are also driven by intrinsic modes of climate variability – the strongest of which is ENSO.

  8. Natural variations Sensitivity to model formulation Response to climate change Teleconnections Predictability Scale interactions Observing system evaluation Forecasts State-of-the-art GCMs Projections Conceptual models Products Tools Data assimilation Paleo reconstructions Long runs Large ensembles GFDL leading groundbreaking research on ENSO Science International engagement: IPCC Fifth Assessment (AR5) U.S. National Multi-Model Ensemble (NMME) Working Group on ENSO Diversity (U.S. CLIVAR) Working Group on ENSO Metrics (CLIVAR Pacific Panel) ENSO Task Team (CLIVAR)

  9. ENSO improvements at high resolution Delworth et al. (JC 2012) SSTA weakens & shifts eastward PNA response strengthens & shifts eastward

  10. ENSO's impacts on regional climates Obs Model

  11. Extreme ENSO events have nonlinear impacts Rainfall teleconnections in CM2.1 (4000yr) West Eq Pacific East Eq Pacific Southeast U.S. Surface temperature teleconnections in CM2.1 (4000yr) West Eq Pacific East Eq Pacific Southeast U.S. 1860 La Niña El Niño

  12. Increasing CO2 alters ENSO impacts Rainfall teleconnections in CM2.1 (4000yr & 400yr) West Eq Pacific East Eq Pacific Southeast U.S. Temperature teleconnections Surface temperature teleconnections in CM2.1 (4000yr & 400yr) West Eq Pacific East Eq Pacific Southeast U.S. 4xCO2 1860 La Niña El Niño

  13. Summary Two key factors affecting future climate vulnerability: 1. Surface temperature trends a. CMIP5 models broadly capture historical trends in surface temperatures - so long as both natural and anthropogenic forcings are included b. 2012 MAM temperature anomaly over the eastern U.S. - occurred against a backdrop of global & regional warming trends - models indicate anthropogenic warming accounted for ~35% 2. Intrinsic climate variability (e.g. ENSO) a. Major driver of regional climate variations b. ENSO & teleconnections improve with increasing resolution c. Teleconnections of extreme ENSO events - can be highly nonlinear - key to understanding regional climate vulnerability

  14. NOAA's Climate Adaptation & Mitigation Goal Key objectives addressed by this research:1. Understand the changing climate system and its impacts. - Improve scientific understanding, modeling, predictions & projections, on monthly-to-centennial & global-to-regional scales.2. Assess current & future states of the climate system to inform decisions. - Identify regional, national, and international vulnerabilities. - Inform IPCC assessments through simulations & analyses.3. Enhance public understanding of vulnerability to climate variations. - Communicate climate risks to increase societal resilience. - Communicate strengths & limitations of climate information. NOAA goals: http://www.ppi.noaa.gov/goals

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