Background
Over the last several decades, the Arctic and North Atlantic have undergone substantial changes
- Increased arctic surface air temperature, decreased sea-level pressure and increased polar atmospheric cyclonicity.
- Reduced arctic ice extent and decreased ice thickness.
- Increased Arctic Ocean temperatures in the intermediate Atlantic Water layer (Figure 1) and reduced upper ocean freshwater content.
- Increased North Atlantic water temperature and salinity in the upper 300 m layer (except the subpolar North Atlantic) and widespread cooling and freshening in the 1000-3000 m layer.
- How much of these changes may be attributed to anthropogenic warming and low-frequency variability?
Numerals I–VI indicate temperature sections (°C) taken in 2004.
Large red and yellow arrows indicate two pulses of warm Atlantic Water. The pathways of Atlantic Water are shown schematically by black arrows. Red stars show locations of moorings. (Top) Depth–time diagram of water temperature (°C). (Middle and bottom) Time series of water temperature (°C) from Fram Strait and Svinoy locations.
