Proxy based reconstructions and results from climate models can both be used to study past climate changes. Data assimilation allows to combine them in order to obtain estimates of the past climate changes that are consistent with the proxies, the physics of the models and the forcings that drive these models. Here, this method is applied to the model LOVECLIM  to have a representation of the Northern Hemisphere sea-ice during the mid-Holocene. The proxy database used to constrain LOVECLIM results is derived from the dinocysts content of 19 cores collected in the North Atlantic and Arctic Oceans .
 Goosse, H. et al. (2010). Description of the Earth system model of intermediate complexity LOVECLIM version 1.2. Geoscientific Model Development, 3(2):603-633.
 de Vernal, A. et al. (2013). Dinocyst-based reconstructions of sea ice cover concentration during the Holocene in the Arctic Ocean, the northern North Atlantic Ocean and its adjacent seas. submitted to Quaternary Science Reviews.
The project I was working for is Past4Future, a Collaborative Project under the 7th Framework Programme of the European Commission. Past4Future aims at investigating the climate and environment of past interglacials to inform on future climate and possible abrupt changes.