CAREER: Understanding the Local and Remote Drivers of Regional Climate Change

University Of Hawaii, Honolulu

Investigators

Abstract

The warming effect of greenhouse gases is global but not uniform over the globe, and regional differences in the warming have important consequences for climate change impacts. El Nino events provide a useful point of reference for the importance of differential warming over tropical oceans, as the warming of the eastern equatorial Pacific relative to the western Pacific causes disruptions in weather and climate worldwide. An assessment of future climate impacts over, say, the Southwest US, would have to take into account not only the magnitude of the warming of the tropical oceans but the pattern of the sea surface temperature (SST) increase. But despite considerable research a clear understanding of what the warming pattern should be and what factors determine it has not yet emerged. In particular, it is not clear how much the SST difference between the tropics and subtropics will change and wether the warming pattern in the Pacific will look more like El Nino or La Nina (with greater warming in the western Pacific). Research conducted under this award addresses the warming pattern using a suite of climate model experiments to identify the physical mechanisms that influence the SST warming pattern and its possible evolution over time. Further work considers the implications of the warming pattern for precipitation changes around the world. The model simulations are performed through a Model Intercomparison Project (MIP) organized by the Principal Investigator (PI) and involving collaborators at the University of Tokyo, the Alfred Wegener Institute in Germany, National Taiwan University, and the Ulsan National Institute of Science and Technology in South Korea. The simulations use a hierarchy of model configurations and specialized techniques to isolate mechanisms of interest. The work is based on an earlier study by the PI and others in which radiative heating by greenhouse gases was applied only in specific latitude bands, with the somewhat unexpected result that off-equatorial heating made a greater contribution to equatorial SST increase than local heating over the equator. Additional experiments use the "flux correction" technique to examine the effect of mean state bias in determining the warming pattern, motivated by concerns that the commonly occurring cold bias in equatorial Pacific SSTs could cause climate models to produce an incorrect warming pattern. The educational component of this CAREER proposal focuses on the use of graphic art as a tool for climate science communication. The project convenes a series of workshops for students in local media and graphic arts programs to develop scientific visualizations to explain climate change impacts relevant to Hawai'i. The visualizations, also known as infographics, are developed in partnership with local K-12 schools to reflect community concerns regarding climate change. The resulting infographics are distributed throughout schools across the state to help increase science literacy. Graphic design concepts are also introduced to graduate students in a new climate dynamics class, with the goal of creating publication-quality scientific illustrations. The infographics workshops serve to introduce climate science concepts to students outside STEM disciplines, many of whom are Native Hawaiians and Pacific Islanders. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.