DEEP WATER FORMATION RESPONSE TO THE 2018 SUDDEN STRATOSPHERIC WARMING EVENTS
Sudden Stratospheric Warming (SSW) events can divide the polar vortex or displace it. Using the methodology of Charlon and Polvani (2007) that consideres the zonal mean of zonal winds at 60ºN and 10hPa and an Regional Ocean Modeling System (ROMS), specifically designed for the Icelandic Exclusive Area (IEA), this study analyzes the SSW downward effect of the 2018 split SSW events that took place. The ROMS model is built with 35 vertical layers and accounts for 14 main rivers around Iceland’s geography. Further, it is fed with atmospheric data from ERA, ocean input data from the GLORYS reanalysis, and TPXOv9, which incorporates 8 main tidal components. Our findings demonstrate that three months after the SSW 2018 event, the positive stratospheric anomalies weaken. This leads to an early March period of persistent downward vertical flux from the stratosphere towards the surface and a cold anomaly at the surface (1000hPa). The cool atmospheric anomaly matches with negative sea surface temperature anomalies and large ocean-atmospheric radiation fluxes. Hence cool sea surface anomalies develop and generate large mix-layers within days that lead to strong negative peaks of dense water south east and west of Iceland. Furthermore the diversion of storm stacks is also a focus of study due to the large radiation fluxes.