1 / 15

Atmospheric Warming and the Amplification of Precipitation Extremes

Atmospheric Warming and the Amplification of Precipitation Extremes. Brian Soden University of Miami Richard Allan University of Reading. We Expect an Increase in Heavy Precipitation. Changes in Column Water Vapor During ENSO. La Nina (cold). El Nino (warm). El Nino. La Nina.

adara
Télécharger la présentation

Atmospheric Warming and the Amplification of Precipitation Extremes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Atmospheric Warming and the Amplification of Precipitation Extremes Brian Soden University of Miami Richard Allan University of Reading

  2. We Expect an Increase in Heavy Precipitation

  3. Changes in Column Water Vapor During ENSO La Nina (cold) El Nino (warm) El Nino La Nina

  4. Response of Precipitation Extremes to ENSO Heavy 9 6 3 -3 -6 -9 (%) Extreme precipitation increases as atmosphere warms and moistens. Light Allan and Soden (2008)

  5. Response of Precipitation Extremes to ENSO: Observations vs GCMs Warm (El Nino) Cold (La Nina) • Heavy rain events increase in frequency during warm/moist periods. • Heavy rain events decrease in frequency during cold/dry periods. • Qualitatively supports GCM projections of increased precipitation extremes. Allan and Soden (2008)

  6. Sensitivity of Precipitation Changes to SST • On average, models underpredict sensitivity of heaviest rain events to DSST • There is a large intermodel spread in the responses of heaviest rain events Allan et al. (2010)

  7. Change in Daily Upward Vertical Velocity (500 )IPCC AR4 Models 2100-2080 minus 2020-2000 Strongest updrafts become less common Weakest updrafts become more common • Heavy rainfall events increase despite weaker “updrafts” Gastineau and Soden 2009

  8. Summary Points • Observations and GCM simulations (AMIP3) both show an increase in heavy precipitation events associated with warmer and moister conditions during El Nino. • The observed suggest a larger sensitivity to SST than ensemble mean GCM simulations or Clausius Clapeyron scaling. • The GCM response to SST is highly varied, and increased heavy rain events are associated with weaker ‘dynamics’ in the model. • The general tendency for weaker precipitation sensitivity is qualitatively consistent with other findings.

  9. Tropical-mean Precipitation Trends: Ascending vs. Descending Regimes All Ascending Descending Allan and Soden (2009)

  10. Extra Slides

  11. Model Projected Change in Daily Upward 500: IPCC AR4 Models 2100-2095 minus 2000-1995 Global Tropical Extra-tropical • Reduction in intensity of strongest “updrafts” is a robust projection of AR4 models. • Heavy rainfall events increase despite weaker “updrafts”. Gastineau and Soden (2009)

  12. Model Projected Change in Most Intense “Updrafts”: IPCC AR4 Models Multi Model Ensemble-Mean Reduction in strongest “updrafts” occurs everywhere except central and eastern Pacific. Gastineau and Soden 2009

  13. Model Projected Change in Precipitation and Upward 500 : IPCC AR4 Models Global Tropical Extra-tropical Precipitation Upward 500 Gastineau and Soden 2009

  14. Precipitation Variability: Changes in Extremes Extreme precipitation increases as atmosphere warms and moistens.

More Related