Satellite observations show expanding Antarctic sea ice over the last three decades. Increasing Antarctic sea ice seems unexpected when compared to observations of rising global temperatures or shrinking Arctic sea ice. Computer models of global climate also predict Antarctic sea ice to shrink instead of grow. Several hypotheses have been suggested to explain the contradiction between what scientists expect to see based on computer models and physical intuition and the growth that is recorded in observations. This study will examine the hypothesis that sea ice expansion can be explained by sea ice motion, where sea ice moves in such a way as to promote an increase in overall coverage. Researchers will use several different types of computer models, ranging in complexity, to better understand the physical processes of sea ice motion and how the sea ice motion interacts with the larger atmosphere-ocean system. The team will transfer their research to the classroom by hosting a week-long teacher workshop. Teachers will learn how scientists use computer models to test hypotheses and then develop and test tools for use in the classroom. Five middle and high school teachers will participate and become part of the UC San Diego STEM Success Initiative master science teacher network. The project will support a graduate student and a postdoctoral researcher.
Sea ice motion has recently emerged as one of the candidates to explain the Antarctic sea ice expansion but a systematic investigation of how sea ice motion influences sea ice concentration has not been presented to date. Researchers will conduct a process-oriented study of the relationship between sea ice motion and Antarctic sea ice extent using a hierarchy of models. The hierarchy will consist of (i) an idealized single-column model of sea ice evolution, (ii) an idealized latitudinally-varying global model of sea ice and climate, (iii) an atmospheric global climate model (GCM) above a slab ocean that includes sea ice motion, (iv) a comprehensive GCM, and (v) model output from the suite of current comprehensive GCMs. The range of model complexities will help researchers better understand the relationship between sea ice motion and sea ice extent by allowing them to identify important processes that are robust across the model hierarchy.
