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Abstract Arctic warming under increased CO2peaks in winter, but is influenced by summer forcing via seasonal ocean heat storage. Yet changes in atmospheric heat transport into the Arctic have mainly been investigated in the annual mean or winter, with limited focus on other seasons. We investigate the full seasonal cycle of poleward heat transport modeled with increased CO2or with individually applied Arctic sea‐ice loss and global sea‐surface warming. We find that a winter reduction in dry heat transport is driven by Arctic sea‐ice loss and warming, while a summer increase in moist heat transport is driven by sub‐Arctic warming and moistening. Intermodel spread in Arctic warming controls spread in seasonal poleward heat transport. These seasonal changes and their intermodel spread are well‐captured by down‐gradient diffusive heat transport. While changes in moist and dry heat transport compensate in the annual‐mean, their opposite seasonality may support non‐compensating effects on Arctic warming.
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Sea-ice loss amplifies summertime decadal CO2 increase in the western Arctic Ocean
Rapid climate warming and sea-ice loss have induced major changes in the sea surface partial pressure of CO2 ( pCO2I). However, the long-term trends in the western Arctic Ocean are unknown. Here we show that in 1994–2017, summer pCO2I in the Canada Basin increased at twice the rate of atmospheric increase. Warming and ice loss in the basin have strengthened the pCO2I seasonal amplitude, resulting in the rapid decadal increase. Consequently, the summer air–sea CO2 gradient has reduced rapidly, and may become near zero within two decades. In contrast, there was no significant pCO2I increase on the Chukchi Shelf, where strong and increasing biological uptake has held pCO2I low, and thus the CO2 sink has increased and may increase further due to the atmospheric CO2 increase. Our findings elucidate the contrasting physical and biological drivers controlling sea surface pCO2I variations and trends in response to climate change in the Arctic Ocean.
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- PAR ID:
- 10165808
- Date Published:
- Journal Name:
- Nature Climate Change
- ISSN:
- 1758-678X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1038/s41558-020-0784-2
