GULF STREAM PATH INFLUENCES ON WINTERTIME SYNOPTIC STORM TRACK AND GREENLAND BLOCKING

In a previous study we examined the relationship revealed between year-to-year changes in the meridional path of the separated Gulf Stream in the NW Atlantic Ocean and the location and properties of the atmospheric synoptic storm track as revealed in the MERRA re-analysis of the vertically integrated transient eddy heat flux carried by synoptic (2-8 days) variability in the wintertime (JMF) troposphere of the northern hemisphere. We have extended by 3 three years the initial 31 year analysis (now 1979-2012, inclusive) and have expanded the atmospheric time scale to include persistent (≥5 days) wintertime blocking events. We will focus on cases in which the year-to-year changing atmospheric variability lags the Gulf Stream and will interpret the correlative relationship as arising in the atmosphere because of changes in the latitude of the zonal path of the separated Gulf Stream. The nature of the relationship is that southward (northward) Gulf Stream paths are associated with an enhanced (reduced) and zonally extended (contracted) storm track towards Europe at mid-latitudes, and with enhanced (reduced) blocking over the southern part of Greenland. Results will be summarized using both linear regression and compositing based on the decadally-varying Gulf Stream path.