Abnormality of thermal structure and current in the upper western tropical Pacific Ocean and its effect on subtropical high

Mainly on the basis of the data obtained during PRC/US bilateral TOGA cruises,abnormal variation occurred during the 1986/1987 El Nino is shown in this paper about the thermal structure and circulation of the upper western tropical Pacific Ocean.The effects of the abmormal variation on the subtropical high over the Northwest Pacific Ocean are discussed.During the El Nino:(1) In the east part of the western tropical Pacific Ocean (the subsurface temperature data on the 165°E section are taken as an example),the water wanner than 29℃ in the upper layer spread on the longitudinal section and positive temperature anormalies appeared in a large area of the sea surface.(2) In the west part of the western tropical Pacific Ocean (the subsurface temperature data on the 137°E section are representative),the cross section occupied by the upper layer warmer water (T>28℃) became shrunk,and the sea surface temperature showed negative amomalies.(3) The eastward flows in the upper layer of the 165°E section strengthened.(4)The northward flow volume of warm water from the origin area of Kuroshio,i.e.,the tropical ooeattic area south of 18°20'N and from the west of 130°E to the Philippine coast,decreased.When those kinds of abnomal variation occurred,air divergence on the low level (1 000 hPa) over the Northwest Phcltlc Ocean was interuified,favourable to the strengthening of subtropical high over the Northwest Paclfic Ocean.