Precession modulation of the poleward expansion of atmospheric circulation to the Arctic Ocean

Arctic climate is projected to become more sensitive to changes in North Pacific meridional heat transport under global warming. This is postulated as a consequence of low-high latitude teleconnections, but the exact underlying mechanisms remain poorly understood. Here, we reconstruct subarctic humidity changes over the past 400 kyr to investigate the role of low-high latitude interactions in regulating Arctic hydroclimate. Our reconstruction is based on precipitation-driven sediment input variations in the Subarctic North Pacific (SANP), which reveal a strong precessional cycle in the subarctic humidity under relative low eccentricity conditions over the past four glacial cycles. Combined with new model simulations, we demonstrate that the observed cyclic hydroclimate changes can be attributed to meridional shifts in the northern rim of the subtropical ocean gyre through affecting water vapor transfer efficiency to the SANP. Our findings support projections of a northward shift of the North Pacific polar gyre in response to future global warming, which will lead to increasingly wet conditions in addition to sea-ice losses in the Arctic Ocean.