An Observational Study of Blocking.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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The initial purpose of this paper was to use the original concept developed by Hartmann and Ghan 1979 of separating the anomalous ridges solely on the basis of duration and proceed to formulate 3-dimensional pictures from the 1000, 850, 500, and 100mb pressure levels of the long and short lived ridges, observing any differences which might exist. The three areas of ridge formation studied were defined as the Pacific Oean 175E-155W, the Pacific Coast 140W-115W, and the Atlantic Ocean 65W-25E. The Pacific regions were characterized by a well developed upstream trough, the ridge itself, and the downstream wavetrains. Both Pacific cases appear consistent with the idea of enhanced production of wave energy due to heating over either the mid-latitude or tropical ocean as suggested by Hoskins and Karoly 1981. The Atlantic cases did not exhibit the same downstream influences as the Pacific cases. The similarity in the height fields over North America between the short and long-lived ridges and the differences in the thermal fields suggests a relationship between the cold temperatures over North America and the long-lived ridges over the Atlantic. Author