Fig. 3: Wind anomaly fields at an 850-hPa geopotential height.
From: Westerly and Laurentide ice sheet fluctuations during the last glacial maximum
It is simulated by 80% minus 100% of the LIS height under the full LGM boundaries in (a) January, (b) July and (c) annual mean. Vectors (m/s) indicate anomalous wind fields. Shading represents the zonal wind anomaly. The black bold contour is the ice sheet margin. It appears that zonal wind fields over North America and the North Atlantic (160-0 °W; 30-70 °N) show that westerlies (red) flowed meridionally across the North Atlantic, delivering heat from the west to the Northeast Atlantic; we propose that this mechanism melted the southern EIS margins and thinned the ice sheet. Meanwhile, anomalous southerly winds delivered heat from the Gulf of Mexico to the LIS, which we propose facilitated the melting of the southern margins of the LIS and the thinning of the ice sheet in general. The simulation identifies westerlies in the 55-70 °N and easterlies in the 40-55 °N (blue) anomaly fields, implying that the full-height LIS boundaries during the early LGM could also sustain two separate atmospheric-oceanic systems (see text).
