Abstract
Quasi-biennial (about 28-mo) variations in surface pressure occur in the vicinity of the North Atlantic and North Pacific subtropical Highs and subpolar Lows, with harmonic amplitudes of order 0.4 mb. The subtropical Highs undergo quasi-biennial latitudinal and longitudinal oscillations averaging about 1° of latitude, with the Atlantic High apparently oscillating in the northeast-southwest direction and the Pacific High in the northwest-Southeast direction. The quasi-biennial pressure oscillations in the North Atlantic subpolar Low and subtropical High are almost out of phase, implying a relatively strong quasi-biennial variation in surface zonal wind in North Atlantic temperate latitudes. There is evidence for a quasi-biennial variation in frequency of hurricanes and typhoons in the North Atlantic and North Pacific, and of severe storms in the vicinity of India. Within the quasi-biennial framework, an above-average frequency of hurricanes or typhoons is associated with above-average pressure in the respective subtropical Highs.
