CGD - Seminar Series - Clara Deser - Isolating the Effects of Anthropogenic Aerosols and Greenhouse Gases in the CESM1 Large Ensemble

Title: Isolating the Effects of Anthropogenic Aerosols and Greenhouse Gases in the CESM1 Large Ensemble

Speaker: Clara Deser, NCAR

Date: Tuesday, 15 October 2019

Time: 11 am - 12 pm

*Refreshments at 10:45*

Location: Mesa Lab, Main Seminar Room, ML - 132

Abstract: The CESM1 initial-condition Large Ensemble has been widely used to disentangle forced climate change from internal variability at regional scales.  Here, we introduce a complementary set of single-forcing ensembles with CESM1 to study the individual roles of GHG and anthropogenic aerosols in the evolution of multi-decadal trends since 1920, with a focus on large-scale patterns of tropical precipitation and SST. We find that the signal-to-noise of the forced responses relative to internal variability is generally low, limiting attribution. In addition, the forced signals project onto leading patterns of internal variability, confounding interpretation and underscoring the importance of evaluating models’ internal variability. We also investigate the degree to which the responses to GHG and anthropogenic aerosols are additive. Finally, we discuss some preliminary attempts to attribute evolving trends in the observational record, in light of the prominent role of internal variability and data constraints.

For more information, contact Tracy Baker,, 303-497-1366


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Will this event be webcast to the public by NCAR|UCAR?: 
Announcement Timing: 
Monday, October 14, 2019 to Tuesday, October 15, 2019
Calendar Timing: 
Tuesday, October 15, 2019 - 11:00am to 12:00pm

Posted by Tracy Baker at ext. 1366,

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