Satellite-observed sea ice area flux through Baffin Bay: 1988–2015

Abstract

Abstract. Sea ice export through Baffin Bay plays a vital role in modulating the meridional overturning process in the downstream Labrador Sea. In this study, satellite-derived sea ice products are explored to obtain the sea ice flux (SIF) through three passages (referred to as A, B, and C for the north, middle, and south passages, respectively) of Baffin Bay. Over the period 1988–2015, the average annual (October–September) sea ice area export is 555 × 103 km2, 642 × 103 km2, and 551 × 103 km2 through passages A, B, and C, respectively. These amounts are less than that observed through the Fram Strait (FS, 707 × 103 km2). Clear increasing trends in annual sea ice export on the order of 53.1 × 103 km2/de and 43.2 × 103 km2/de are identified at passages A and B, respectively. The trend at the south passage (C), however, is slightly negative (−13.3 × 103 km2/de). The positive trends in annual SIF at A and B are primarily attributable to the increase during winter months, which is triggered by the accelerated sea ice motion (SIM) and partly compensated by the reduced sea ice concentration (SIC). During the summer months, the sea ice export through each Baffin Bay passage usually presents a negative trend, primarily because of the decline in SIM and it is further enhanced by a dramatic decrease in SIC. A significant positive trend in the net SIF (i.e. net ice inflow) is found for between the passages A (or B) and C at 54.5 (or 64.2) × 103 km2/de. Therefore, Baffin Bay may have presented a greater convergence of ice. Overall, the connection between Baffin Bay sea ice export and the North Atlantic Oscillation (NAO) is tenuous, although the correlation is sensitive to variations in the selected time period. In contrast, the association with the cross-gate sea level pressure difference (SLPD) is robust in Baffin Bay (R = 0.69–0.71 depending on the passages), but relatively weaker compared with that in the FS (R = 0.74). Baffin Bay is bounded by Baffin Island to the west and Greenland to the east, thus, sea ice drift is not converted to the free state observed in the FS.