European regional climate change: A human signal?

Aims

• What are the causes of recent changes in European climate?

Observed Datasets

• Two gridded precipitation datasets from GPCC. Global at resolution of 1x1– vn 4 1901-2007– VASCLIMO 1951-2000. More attention paid to

homogeneity

• CRUTEMP3 -- land temperature record at resolution of 5x5.

• EWP – England and Wales Precipitation• CET – Central England Temperature

Regions

Average Precipitation (mm/month) for Europe during 61-90. Shown are regions used for study.

Med

Western Europe

Northern Europe

“England”

Simulated data

• Use a set of simulations carried out for the 4th Assessment report. (WCRP archive)

• Simulations forced with both Natural and Human drivers. – From 1890 (or earlier) to 2100 (A2). 22– From 1890 (or earlier) to 1999. 57

• Simulations forced with natural only drivers– From 1890 to 1999. 29

• Control simulations (Constant forcing) 4500 years

Data processing

• Simulated monthly-mean data interpolated to observed grid

• Masked by observed data (only have simulated data where there are observations)

• Convert precipitation data to percentage anomalies relative to 61-90. (if keep as total will be focused to regions with high precipitation)

• Temperature data as anomalies relative to 61-90• Data averaged over regions to produce time series.• Time-series averaged to produce warm (May-Oct) and

cold (Nov-Apr) seasons.

Testing model variability

Detection

AttributionDifferent model simulations = different symbols. X means inconsistent

Warm

Cold

Summary

• Likely that European regional climate is changing due to human influences

• Warming throughout year• Strongest precipitation signals in “cold”

season– Drying in Med and moistening in other regions– “England” showing summer drying as well

• Combined analysis of Precip and Temperature better than each individually.