Research Document - 2016/079
Physical Oceanographic Conditions on the Newfoundland and Labrador Shelf during 2015
By Colbourne, E., Holden, J., Senciall, D., Bailey, W., Snook, S., and Higdon, J.
An overview of physical oceanographic conditions in the Newfoundland and Labrador Region during 2015 is presented as part of the Atlantic Zone Monitoring Program (AZMP). The North Atlantic Oscillation (NAO) Index, an indicator of the direction and intensity of the winter wind field patterns over the Northwest Atlantic, remained in a positive phase in 2015, reaching a record high resulting in a strong arctic air outflow in the northwest Atlantic during the winter months and consequently lower than normal winter air temperatures. Sea ice extent increased substantially during winter 2014 with the first positive anomaly (higher-than-normal extent) observed in 16 years and in 2015 the total extent was about normal except for March and April when it was above normal. Annual sea-surface temperatures (SST) based on infrared satellite imagery across the Newfoundland and Labrador (NL) Shelves ranged from near-normal to below normal in some areas. The cold-intermediate layer (CIL; volume of <0°C) in 2015 was at its highest level on record (since 1970) on the Grand Bank during the spring. The annual bottom (176 m) water temperature at the inshore monitoring station (Station 27) was below normal in 2015 by -0.7 standard deviations (SD), a significant decrease from the record high in 2011. Spring bottom temperatures in 3Ps remained above normal by about 0.5°C (0.8 SD) and were about normal on the Grand Banks. Fall bottom temperatures in 2J, 3K and 3LNO decreased from 2, 2.7, and 1.8 SD above normal in 2011 to 0.2 and 0.8 SD above normal in 2J and 3K and to -0.4 SD below normal in 3LNO in 2015, a significant decrease in the past four years. A standardized climate index derived from 28 meteorological, ice and ocean temperature and salinity time series declined for the 4th consecutive year, reaching the 7th lowest in 66 years and the lowest value since 1993.
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