January 2016

Mohammad Hadi Bordbar is back from Australia and reports about his Miniproposal.


Uncertainty in Tropical Pacific Climate Projections Due to Chaotic Atmospheric Forcing and Initial Conditions


Mohammad Hadi Bordbar, GEOMAR

Despite the ongoing increase in anthropogenic CO2 emission, globally averaged surface air temperature does not show significant warming during the last decade. Large part of this hiatus in global warming is attributed to cooling in the central and eastern tropical Pacific and intensification of Pacific Walker Circulation which is not reproduced by many climate models. Using the Kiel Climate Model (KCM) ensemble of global warming experiments initialized from different climate states, we detected large uncertainty over the tropical Pacific and realized that some ensemble members capturing the recent observed changes reasonably well.
It was the main motivation of the mini-proposal to explore whether this result could be confirmed with other climate models employing a similar experimental set-up. Due to their extensive expertise in climate modeling and outstanding research in the tropical climate, I decided to accomplish this work in collaboration with Matthew England and his research group in the Climate Change Research Center (CCRC) of the University of New South Wales, Sydney.
The visiting programme was most fruitful and produced conclusive results. Our findings indicate the dominant influence of long-term internal variability, primarily originating from stochastic atmospheric processes, in the 21st century tropical Pacific climate projections. Our results outline the large influence of the Pacific mid- and high latitudes on the strength of the tropical Pacific Trade winds. We also found that the ocean has decadal-scale memory from the initial climate state in large parts of the tropical sector, which may provide new insight for advancing tropical climate predictability. I have the intention of advancing my research which started with the mini-proposal and collaborating further with the CCRC.
Initializing, writing and carrying out the miniproposal was a valuable experience for me in developing and implementing my own innovative ideas, which is an essential step for being an independent researcher. Practically, I learned how to manage the time-schedule to fulfill the anticipated milestone in an efficient way. Furthermore, the CCRC interacts closely with the public media which was a great opportunity for me to find out how influential my research is on the views of the general public about the concept of human-induced climate change and global warming.