Abstract
Interdiurnal variations of sea level pressure and surface temperature are studied using the WMONEX/FGGE level II-b data set for the region bounded by 30N-10S and 100E-130E during December 1978. Results of spatial cross correlation patterns indicate an eastward phase propagation of pressure and temperature maxima with speed∼10 longitude per day over the Southeast China and adjacent ocean, apparently associated with the travelling midlatitude disturbances. In the meridional direction, pressure oscillations in the midlatitudes are highly correlated with that over Indochina for three consecutive days but not with those over the bulk of the South China Sea. This difference in correlations indicates a change in the characteristics of the air mass as it traverses land and sea. Temperature analysis also implies the influence of heat transfer between the ocean and atmosphere to the areas south of 15N.
An eigenvector analysis is applied to both the pressure and the temperature series. The first eigenmode resembles the pattern associated with the East Asia local Hadley circulation. The second eigenvector represents wintertime anticyclone and cyclone patterns over Southeast China and its adjoining ocean, and thus the cold surge events. Time series of the first two eigenmodes are discussed in terms of the winter monsoon circulation during this period.
