ИСТИНА

Earth system models (ESM) are now widely used for palaeoreconstructions. In this study, we analyze results of the numerical experiment aiming at simulation of climate of the penultimate (Eemian) interglacial (last interglacial, LIG). Numerical experiment was carried out using an ESM designed in the Institute of Numerical Mathematics of RAS. Orbital parameters were set with 1 kyr periodicity and were further interpolated with the time step of 100 years. Assuming concentrations of greenhouse gases during the LIG were not very much different from the preindustrial values, this potential forcing was neglected. Climatic block of the ESM was called every 100 model years to follow changes in orbital forcing. Sub-models of ice sheets were asynchronously coupled to sub-models of the atmosphere and the ocean with the ratio of model years as 100 to 1. Obtained anomaly (Eemian vs preindustrial) fields of surface air temperature correspond in general to the results of the earlier studies. Changes in the structure of the global atmospheric circulation yeilded in transformation of the precipitation field in certain regions of the world. In particular, precipitation growth in Northern Africa was the reason for the radical change of landscapes. In the frameworks of the study, we evaluated the role of the Greenland ice sheet in the rise of the mean level of the World Ocean. Its estimated contribution (2 m) confirms the newest estimates based on the model results and analysis of the proxy data. In the beginning of the Eemian interglacial (until 126 years before present) mass lost occurs across the marine boundary of the sheet. During the next five millennia, negative surface mass balance plays the leading role. Taking into account contributions of the Greenland ice sheet, ocean thermal expansion and melting of mountain glaciers and ice caps, it is very probable that the main source the global sea level growth to 6-9 m compared to present was the West Antarctic ice sheet.