A 5-year climatological survey of the Gulf Stream System's landward surface edge defines the mean, standard deviation, extreme limits, annual and interannual variabilities, and frequency distributions along 0.5¿ longitudinal transects from 91¿ to 44 ¿W. The climatology covers the Loop Current in the Gulf of Mexico and the Gulf Stream in the northwest Atlantic Ocean. Autocorrelations and power spectra are derived for longitudinal transects between 79.5¿ and 57.5 ¿W. The study also investigates the observed warm-core ring and cold-core ring movements and their areal extent. The observed data are compiled from the Oceanographic Analysis charts (produced by the National Oceanic and Atmospheric Administration) which utilize infrared satellite imagery and in situ observations. East of Cape Hatteras the Gulf Stream System Landward Surface Edge exhibits both interannual and annual signals. The interannual Stream System Landward Surface Edge exhibits both interannual and annual signals. The interannual variability is equal to the annual variability. The mean monthly Gulf Stream position for the longitudinal band 70¿--44 ¿W shifts from farthest north in September to farthest south in February. The magnitude of the annual shift is largest near the Grand Banks. Frequency distributions of the Gulf Stream System position are quasi-normal nearly everywhere. Autocorrelation plots from the 5-year time series of Gulf Stream positions at longitudinal transects 79.5¿--57.5 ¿W exhibit three well-defined e-folding time regimes with a maximum time of 10 weeks at 72 ¿W. Power spectrums from 79.5¿ to 57.5 ¿W are red spectrums having dominant peaks of 1-year period or greater.

The largest total spectra energies are found at 61 ¿W. The Loop Current sheds rings at two apparent spatial scales which are labeled major (307-km mean) and minor (185-km mean) warm-core rings. Annually, the Loop Current sheds about one major warm-core ring which translates into the western basin of the Gulf of Mexico and one minor warm-core ring which is ususally reabsorbed by the Loop Current. The major Loop Current warm-core ring sheddings have no seasonal preference. Loop Current warm-core rings have a mean velocity of 2.4 km/d west-southwest. An average of 22 Gulf Stream warm-core ring absorptions is found near the New England Seamounts, while the largest frequency of warm-core ring absorptions is found near Cape Hatteras. Gulf Stream warm-core rings can absorb each other as occurred in 14% of the absorption cases with the highest frequency just upstream of the New England Seamounts. The Gulf Stream warm-core rings have a surface diameter decay rate of -0.026 per week (Loop Current warm-core rings are similar). The Gulf Stream warm-core rings have a mean velocity of 2.4 km/d west-southwest. Cold-core rings have a mean cool-core surface diameter of 105 km and amean velocity of 1 km/d southwest. More definitive conclusions on cold-core rings are not possible, as ring identification and tracking by satellite infrared imagery is tentative. ¿ American Geophysical Union 1987