Radiosonde data and surface meteorological data collected from the moorings and ships on both the warm and cold sides of the North Atlantic subtropical front were analyzed for the January to June 1986 time period. These data were used to investigate the magnitude and the spatial-temporal scales associated with the variation of the wet tropospheric range correction for the U.S. Navy's Geosat radar altimeter. Analysis consisted of both numerical integration of high-resolution radiosonde and use of an atmospheric model to calculate the wet tropospheric range correction for the study region during the January--June 1986 period. Results shows that the wet tropospheric range correction varied by about 15 cm overall, i.e., ranging from approximately 10 to 25 cm. This variation however, occurred over length scales which were large and time scales which were short compared with those from the subtropical front. Based on the results, the wet tropospheric range correction represented a synoptic scale variation in the lower atmosphere which would have little effect on the mesoscale dynamic signal associated with the subtropical front of the mesoscale eddy field as measured by the Geosat altimeter. ¿ American Geophysical Union 1989