Paleo Arctic Ocean Hydrograph And Circulation In Last Glacial Maximum As Obtained From NAOSIM Model

Along with the economy development, nature is bearing more and more pressure from human activities. This would make severe sense to the process of the Earth climate changing between glacial and interglacial periods. Reconstructing paleo ocean circulation in Last Glacial Maximum is a most important step to find the trigger of climate regime shift.It is currently thought that the Arctic Ocean could impact global climate by regulating deepwater formation rates. In addition to the global ocean hydrological cycle, most part cryosphere distributed in the polar region, is also a dominant element to the earth's climate change.Our aim is to study the dynamics and thermodynamic mechanism of paleo Arctic Ocean circulation. We choose North Atlantic-Arctic Ocean Sea Ice Model (NAOSIM), which is well coupled with the ocean circulation and sea ice, also involving atmosphere forcing, river discharge and land-sea mask into account. In the past numerical simulation, this model has a good performance in the Arctic regions.In LGM, the glacial forcing conditions have Arctic Ocean circulation perform totally different from the present. The nearly closed ocean basin and very thick'ice cap'make the currents structure totally isolated from the atmosphere forcing, and less effected by lower latitudes water mass. The domain mechanism to the surface circulation is the potential voticity conservation, overlapping with the dynamics and thermodynamics effects from paleo rivers. The sea ice friction consumes the kinetic energy by friction. The vertically constant horizontal currents could indicate the details of topography well.The surface Fram Straight is ruled by Arctic Ocean outflows, and a strong Nordic Seas current enters the straight, through the subsurface and intermediate layers. Nordic Seas circulation basically obeys the potential voticity conservation, but it is very sensitive to the water mass balance with the Arctic Ocean and North Atlantic Ocean. In the realistic LGM experiment, the existing of paleo river mostly rules the basin-scaled cyclone gyre. Mostly North Atlantic Ocean water is mixed with the East Greenland current in the north of Ice Island, and then transported to the Fram Straight by"Nowegian-Arctic"ocean current.Arctic Ocean is completely covered by perennial average 15m thickness sea ice in LGM. Sea ice thickness distribution is influence by the fresh water discharge from paleo rivers, which could be regard as a heat source. The ice-drifting routings in Arctic Ocean is almost the same in each season. Arctic Sea ice is transported to the Labrador Sea by a branch of East Greenland current. The Nordic Seas Sea ice performs different features from west to east, which is validated very well by the sediment cores proxy data.