This study investigates the physical processes and mechanisms driving the interannual variability of deep convective intensity in the Greenland Sea from 1993 to 2016. The intensity of deep convection is derived using the traditional Maximum Mixed Layer Depth, the total surface area with the monthly-mean mixed layer depth exceeding 800 m and various indices. All metrics show that the intensity of convection increased during the 2000s.

The analysis demonstrates that observed increases of the deep convective intensity in the Greenland Sea is associated with an increase in the upper ocean salinity. The long-term interannual variability of deep convection is mainly linked to the variation of the water salinity during the preceding summer and the current winter. In turn, the variability of the upper-ocean salinity is primarily related to the variability in the advection of Atlantic water into the region with the re-circulating branches of the West Spitsbergen Current and to a lesser degree, to the local sea ice melt. For only two winters during the study period did the sea ice contribute significantly to a weakening of the intensity of deep convection by substantially reducing oceanic heat loss to the atmosphere. The variability in the advected heat is effectively abated by the concurrent variations of oceanic heat release to the atmosphere. The interplay between the interannual variability of the oceanic heat advection and the winter air-sea net heat flux leads to a noticeable reduction of the interannual variability of both fluxes over the convective regions. As a result, the direct effect of the varying air-sea heat exchange did not have a pronounced direct effect on the interannual variation in the intensity of deep convection in the Greenland Sea, at least during the study period.

本研究调查了驱动格陵兰海 1993 年至 2016 年深对流强度年际变化的物理过程和机制。层深超过 800 m 和各种指数。所有指标都表明对流强度在 2000 年代有所增加。

分析表明，观测到的格陵兰海深对流强度的增加与上层海洋盐度的增加有关。深对流的长期年际变化主要与前夏和今冬水盐度的变化有关。反过来，上层海洋盐度的变化主要与大西洋水平流进入西斯匹次卑尔根海流再循环分支区域的变化有关，在较小程度上与当地海​​冰融化有关。在研究期间只有两个冬天，海冰通过显着减少向大气中损失的海洋热量，显着削弱了深对流强度。海洋热释放到大气中的同时变化有效地减弱了平流热的变化。海洋热平流年际变化与冬季海气净热通量之间的相互作用导致对流区这两种通量的年际变化显着减少。因此，变化的海气热交换的直接影响对格陵兰海深对流强度的年际变化没有明显的直接影响，至少在研究期间是这样。海洋热平流年际变化与冬季海气净热通量之间的相互作用导致对流区这两种通量的年际变化显着减少。因此，变化的海气热交换的直接影响对格陵兰海深对流强度的年际变化没有明显的直接影响，至少在研究期间是这样。海洋热平流年际变化与冬季海气净热通量之间的相互作用导致对流区这两种通量的年际变化显着减少。因此，变化的海气热交换的直接影响对格陵兰海深对流强度的年际变化没有明显的直接影响，至少在研究期间是这样。