On the distribution of horizontal transports by transient eddies in the Northern Hemisphere wintertime circulation.

Horizontal fluxes of geopotential, heat, zonal momentum relative vorticity and potential vorticity by the transient eddies on selected pressure surfaces are computed on the basis of data from twice daily synoptic charts for the Northern Hemisphere, objectively analyzed at the US National Meteorological Center. The distribution of fluxes is resolved into nondivergent and irrotational parts and displayed in a vectorial format. The nondivergent flux of geopotential closely parallels contours of constant temporal variance of geopotential. The distribution of transient eddy heat flux in the lower troposphere is primarily irrotational and directed down the local horizontal gradient of the time-averaged temperature field. The irrotational transient eddy flux of zonal momentum at the jet stream level is much smaller than the corresponding flux associated with momentum advection by the time-averaged flow and it is directed into regions of low zonal wind speed. The irrotational flux of geopotential is directed out of regions of decaying transient disturbancecs and into regions of cyclogenesis. -from Authors