TY - JOUR
T1 - Ross ice shelf cavity circulation, residence time, and melting
T2 - Results from a model of oceanic chlorofluorocarbons
AU - Reddy, Tasha E.
AU - Holland, David M.
AU - Arrigo, Kevin R.
PY - 2010/4/30
Y1 - 2010/4/30
N2 - Despite their harmful effects in the upper atmosphere, anthropogenic chlorofluorocarbons dissolved in seawater are extremely useful for studying ocean circulation and ventilation, particularly in remote locations. Because they behave as a passive tracer in seawater, and their atmospheric concentrations are well-mixed, well-known, and have changed over time, they are ideal for gaining insight into the oceanographic characteristics of the isolated cavities found under Antarctic ice shelves, where direct observations are difficult to obtain. Here we present results from a modeling study of air-sea chlorofluorocarbon exchange and ocean circulation in the Ross Sea, Antarctica. We compare our model estimates of oceanic CFC-12 concentrations along an ice shelf edge transect to field data collected during three cruises spanning 16 yr. Our model produces chlorofluorocarbon concentrations that are quite similar to those measured in the field, both in magnitude and distribution, showing high values near the surface, decreasing with depth, and increasing over time. After validating modeled circulation and air-sea gas exchange through comparison of modeled temperature, salinity, and chlorofluorocarbons with field data, we estimate that the residence time of water in the Ross Ice Shelf cavity is approximately 2.2 yr and that basal melt rates for the ice shelf average 10 cm yr-1. The model predicts a seasonal signature to basal melting, with highest melt rates in the spring and also the fall.
AB - Despite their harmful effects in the upper atmosphere, anthropogenic chlorofluorocarbons dissolved in seawater are extremely useful for studying ocean circulation and ventilation, particularly in remote locations. Because they behave as a passive tracer in seawater, and their atmospheric concentrations are well-mixed, well-known, and have changed over time, they are ideal for gaining insight into the oceanographic characteristics of the isolated cavities found under Antarctic ice shelves, where direct observations are difficult to obtain. Here we present results from a modeling study of air-sea chlorofluorocarbon exchange and ocean circulation in the Ross Sea, Antarctica. We compare our model estimates of oceanic CFC-12 concentrations along an ice shelf edge transect to field data collected during three cruises spanning 16 yr. Our model produces chlorofluorocarbon concentrations that are quite similar to those measured in the field, both in magnitude and distribution, showing high values near the surface, decreasing with depth, and increasing over time. After validating modeled circulation and air-sea gas exchange through comparison of modeled temperature, salinity, and chlorofluorocarbons with field data, we estimate that the residence time of water in the Ross Ice Shelf cavity is approximately 2.2 yr and that basal melt rates for the ice shelf average 10 cm yr-1. The model predicts a seasonal signature to basal melting, with highest melt rates in the spring and also the fall.
KW - Antarctica
KW - Basal melt
KW - Chlorofluorocarbons
KW - Ocean circulation
KW - Oceanography
KW - Residence time
KW - Ross Sea
KW - Ventilation
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U2 - 10.1016/j.csr.2010.01.007
DO - 10.1016/j.csr.2010.01.007
M3 - Article
AN - SCOPUS:77950189268
SN - 0278-4343
VL - 30
SP - 733
EP - 742
JO - Continental Shelf Research
JF - Continental Shelf Research
IS - 7
ER -