Historical February / September sea-ice concentration and annual sea-ice cover estimation at the location of core MD88-787 in the Southeast Indian Ocean

Variations in microfossil records in sediments over time are used as proxies for changes in the ocean. One important record determined from microfossils is sea-ice cover which influences, and is influenced by, wind and ocean circulation, atmospheric conditions, and heat balance. Increasing emphasis is being placed on the predictive capabilities diatoms may bear in estimating Antarctic sea-ice, one of the important modulators of Southern Hemisphere climate. The purpose of this study was to estimate past sea-ice concentration and annual coverage at the site of core MD88-787 in the Southeast Indian Ocean. The accumulation of diatom microplankton assemblages in sediments being the proxy for these records of climatic change. \n\nA new method for sea-ice concentration and cover estimation from CABFAC derived factor analysis was developed during this project. Previous estimations of sea-ice have relied on other avenues of deriving limits to the maximum sea-ice edge, while the model developed here made use of modern sea-ice satellite observations combined with diatom distributions that are considered more closely linked to the sea-ice cover.\n\nThree models were proposed which estimated sea-ice concentration in February and September, and annual sea-ice cover.