in the form of rain due to the warm air and sea surface temperatures. This precipitation is also primarily over the ocean. By year ten (Fig. 11), precipitation in the Arctic has subsided. A pocket of intense precipitation persists next to Alaska and Northern Canada due to moist ocean air driven over cold land masses by the jet stream. However, this effect does not generate large amounts of precipitation over Eastern Canada and the Great Lakes region. There is precipitation over the Atlantic next to Greenland’s coast, but it does not penetrate inland, which would aid in building up an ice sheet. Fig. 12 shows the seasonal precipitation pattern for year forty. Precipitation along the western coast of North America continues to be strong and increasingly so along the coast of Greenland during the winter. By this time in the simulation, precipitation has dropped off over most of the Arctic. Sea ice covers the ocean surface, cutting off a major source of water vapor. The reduction in precipitation over the Arctic is clearly seen by year 160 (Fig. 13). Sea ice is thirty meters thick and water vapor comes from evaporation off the ice rather than open water. F. Snowfall and snow depth Combining what is observed about ocean/air temperature and precipitation patterns, it is possible to explain the snowfall pattern. Early in the simulation, snowfall is insignificant due to the warm ocean and air temperatures. However, by year ten (Fig. 14) temperatures have fallen enough for snowfall to occur over land during the hemisphere’s winter season. Snowfall up to 2 mm/day is present in Canada, Scandinavia, Asia, and Antarctica. Over the winter season this results in an accumulation of 0.2 meters. However, during the summer season, Figure 8. Average high surface air temperature for the four seasons during year 160. Figure 9. Average high surface air temperature for the four seasons during year 390. GOLLMER Rapid ice age 2023 ICC 273
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