land-atmosphere coupling and climate change in europe
DESCRIPTION
Land-atmosphere coupling and climate change in Europe. Sonia I. Seneviratne , Daniel Lüthi , et al. Corey Godine, Atmospheric Sciences Program. What is “coupling?”. Studies use two different hypotheses: Surface processes & future changes in radiation budget - PowerPoint PPT PresentationTRANSCRIPT
SONIA I . SENEVIRATNE, DANIEL LÜTHI , ET AL .
COREY GODINE, ATMOSPHERIC SCIENCES PROGRAM
Land-atmosphere coupling and climate change in Europe
What is “coupling?”
Studies use two different hypotheses: Surface processes & future changes in radiation
budget Future summertime atmospheric circulation
modification
Models do not take into account increasing greenhouse gases likely in the future
Coupling = Atmospheric circulations (temperature or precipitation) + Soil moisture
What is “coupling?”
Increased atmospheric greenhouse gases change coupling dynamics
Projected large fluxes in climatic extremes
Humans can’t cope with large variability
Extreme Summers in Europe
HOT2003 heatwave and
drought
COLD2002 and 2005
torrential flooding
The Big Ideas
Goal: Discover role of land-atmosphere coupling in yearly summer temperature & precipitation extremes in Europe
Researchers used several different models
Not a lot of math Great Scot!
Models and Equations
Four 30-year-long experiments (RCM) Two recent (CTL, CTLuncoupled), 1960-1989 Two future (SCEN, SCENuncoupled), 2070-2099 Uncoupled models remove surface influences
Equations:
Models and Equations
Future regional model greenhouse gas scenario based on IPCC specifications 3 numerical global models
Global scenarios from present and futuretaken from 12 different IPCC global models
Analysis
How does land-atmosphere coupling affect the future temperature/precipitation variability in Europe in the future?
Data from each individual model
Differences between each modelExternal forcings only (ie, atmospheric circulations)External forcings + Land-atmosphere coupling
Why such a large change in T?
Large difference between GLACE (a present-climate model) and the model runs on previous page
CTL SCEN
Why such a large change in T?
The percentage of variation in summer temperature due to land-atmosphere coupling
Why such a large change in T?
Models show land-atmosphere coupling is correlated with a higher temperature change
SCEN predicts that land-atmosphere coupling will shift to east and north
Consistent with other recent model runs (IPCC, PRUDENCE)
Evapotranspiration and Temperature
Negative correlation = strong soil control over evapotranspiration (ie, coupling)
Positive correlation = strong atmospheric control over evapotranspiration (ie, uncoupled)
What about precipitation?
Models are less certain about the relationship between land-atmosphere coupling and precipitation variability
Conclusion
Land-atmosphere coupling is strongly affected by an increase in greenhouse gases
Northward shift of European climate zones
Strong positive correlation between land-atmosphere coupling and temperature variability Strong negative correlation between coupling and
evapotranspiration
Weak correlation between land-atmosphere coupling and precipitation variability
Opinions
Temperature correlations convincing Run CTL and SCEN against more coupling models to
confirm results Would like more information about relationship between
evapotranspiration and couplingNeeds more development in precipitation
correlationTeleconnection problems!
Many other process could contribute to projected shift in surface temperatures
Would have liked more accurate/effective global models to supplement regional models
Questions?
Thank you!