Research output: Contribution to journal › Article › peer-review
Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic. / Dukhovskoy, D. S.; Yashayaev, I.; Proshutinsky, A.; Bamber, J. L.; Bashmachnikov, I. L.; Chassignet, E. P.; Lee, C. M.; Tedstone, A. J.
In: Journal of Geophysical Research: Oceans, Vol. 124, No. 5, 05.2019, p. 3333-3360.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Role of Greenland Freshwater Anomaly in the Recent Freshening of the Subpolar North Atlantic
AU - Dukhovskoy, D. S.
AU - Yashayaev, I.
AU - Proshutinsky, A.
AU - Bamber, J. L.
AU - Bashmachnikov, I. L.
AU - Chassignet, E. P.
AU - Lee, C. M.
AU - Tedstone, A. J.
PY - 2019/5
Y1 - 2019/5
N2 - The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km3 since the 1990s. The volume of this surplus freshwater is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveals freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50–100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of freshwater have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
AB - The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km3 since the 1990s. The volume of this surplus freshwater is expected to cause substantial freshening in the North Atlantic. Analysis of hydrographic observations in the subpolar seas reveals freshening signals in the 2010s. The sources of this freshening are yet to be determined. In this study, the relationship between the surplus Greenland freshwater flux and this freshening is tested by analyzing the propagation of the Greenland freshwater anomaly and its impact on salinity in the subpolar North Atlantic based on observational data and numerical experiments with and without the Greenland runoff. A passive tracer is continuously released during the simulations at freshwater sources along the coast of Greenland to track the Greenland freshwater anomaly. Tracer budget analysis shows that 44% of the volume of the Greenland freshwater anomaly is retained in the subpolar North Atlantic by the end of the simulation. This volume is sufficient to cause strong freshening in the subpolar seas if it stays in the upper 50–100 m. However, in the model the anomaly is mixed down to several hundred meters of the water column resulting in smaller magnitudes of freshening compared to the observations. Therefore, the simulations suggest that the accelerated Greenland melting would not be sufficient to cause the observed freshening in the subpolar seas and other sources of freshwater have contributed to the freshening. Impacts on salinity in the subpolar seas of the freshwater transport through Fram Strait and precipitation are discussed.
KW - ARCTIC-OCEAN
KW - CLIMATE
KW - EDDY KINETIC-ENERGY
KW - FLUX
KW - GLOBAL OCEAN
KW - Greenland ice sheet melting
KW - ICE
KW - LABRADOR SEA
KW - MODEL
KW - THERMOHALINE CIRCULATION
KW - VARIABILITY
KW - freshwater anomaly
KW - freshwater budget
KW - passive tracer numerical experiment
KW - subpolar North Atlantic
KW - subpolar gyre
UR - http://www.scopus.com/inward/record.url?scp=85066883753&partnerID=8YFLogxK
U2 - 10.1029/2018JC014686
DO - 10.1029/2018JC014686
M3 - Article
C2 - 31341755
AN - SCOPUS:85066883753
VL - 124
SP - 3333
EP - 3360
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
SN - 0148-0227
IS - 5
ER -
ID: 42786492