Midlatitude Cyclone and North Atlantic Surface Flux Variability and Trends

Abstract:

Midlatitude cyclones tend to occur in the same locations in the North Atlantic, forming the Atlantic sector of the Northern Hemisphere storm track. When the storm track is located so that cold outbreaks occur over places that are preconditioned for convection, deep water formation is more likely. To understand how cyclones influence the atmospheric forcing of deep water formation in the North Atlantic, we identify preferred North Atlantic cyclone locations (“cyclone states”) and associated temperature, humidity, freshwater, and radiative fluxes, and attribute the surface fluxes to physical processes using NASA MERRA (Modern-Era Retrospective Analysis for Research and Applications) surface fluxes, temperature and humidity tendencies and a MERRA-based cyclone climatology. We then quantify the time and space variability and trends of the cyclone states, and how these affect North Atlantic surface fluxes.