{'fraction_non_alphanumeric': 0.021379980563654033, 'fraction_numerical': 0.016034985422740525, 'mean_word_length': 5.091715976331361, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 1, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The bipolar seesaw on the Iberian margin stretching over the past 420,000 years

PAGES News, Vol.16 • No 1 • January 2008 Sp ec ia l S ec tio n: P al eo ce an og ra ph y with an intensification of the subtropical high pressure over the North Atlantic gyre (Lohmann, 2003; Vellinga and Wood, 2002; Vellinga and Wu, 2004). These conditions result in a precipitation deficit in the tropical/subtropical North Atlantic, coupled with a freshening of the tropical/subtropical South Atlantic. Covariation between shifts in the Atlantic ITCZ, as inferred from the Cariaco Basin Fe record, and changes in North Atlantic gyre salinity suggest that a similar oscillation may have operated in the Atlantic during MIS 3 on millennial timescales, resulting in elevated North Atlantic gyre SSS during stadials. Based on these results, it appears that surface waters in the Caribbean and the subtropical gyre became exceptionally salty during glacial/stadial intervals over the last 136 kyr. Correlations between tropical/subtropical SSS change, inferred AMOC variability and meridional shifts in the ITCZ suggest that changes in ocean circulation and the tropical hydrological cycle combined to alter the glacial/stadial Atlantic salinity budget. Results indicate that as the ITCZ migrated southward during stadials, water vapor supply to the North Atlantic decreased and/or water vapor removal increased (Xie et al., 2007). This lead to the accumulation of salt in the tropical/subtropical North Atlantic, which was not advected out of the basin due to reduced AMOC. Therefore, the hydrological cycle may act as a negative feedback during weak phases of AMOC, increasing North Atlantic surface water density and preconditioning the system for a return to an interstadial mode of strong AMOC. More intriguing is the possibility that these elevated stadial gyre salinities played a critical role in maintaining North Atlantic SSS high enough to allow for the rapid resumption of North AMOC, in spite of increased freshwater input associated with interstadial warming events.