Water Vapor Transfer over the Southwest Pacific: Mean Patterns and Variations during Wet and Dry Periods

Abstract

The mean water vapor transfer of the Southwest Pacific, as determined from radiosonde records near the 170°E meridional transect, is computed for the 1960?73 period. Emphasis is placed on defining average patterns, then examining variations that arise during the wettest and driest years and seasons in New Zealand over that period. Over the midlatitudes, the mean transfer is predominantly from the west, and most developed in summer. Over the subtropics, the mean summer transfer is predominantly from the north or northeast, but in winter a northwest flow prevails. Patterns of water vapor transfer during wet and dry periods over New Zealand differ more in direction than in magnitude, with the subtropical easterlies extending farther poleward during wet periods, especially in summer.