DISTRIBUTIONS OF WATER MASSES AND HYDROGRAPHIC STRUCTURES IN THE YELLOW SEA AND EAST CHINA SEA IN SPRING AND SUMMER 2011
2011年春、夏季黄、东海水团与水文结构分布特征

Temperatures and salinities structures and water masses varied significantly with season in the Yellow Sea and East China Sea.The two cruises were carried out in spring(April) and summer(August) of 2011 to investigate the reasons of jelly fish break-out.It was found that(1) 10℃ isotherm which stood for the Yellow Sea Cold Water in summer consisted in the central of the Yellow Sea below the 30m depth,the range extended to 122°E in the west and to 34°N in the south.The lowest temperature was 6.2℃,which was 2.0℃ lower than the average climatological value;(2) The Changjiang River Diluted water spread eastward in semicircle centered in the Changjiang River mouth in summer.No obvious northeastward direction-turning was found and the 30.00 isohaline extended to 124°E in the east and to 29.5°N in the south.The Changjiang River Diluted water extension was about 1°west along 32°N section but distinctly extended to southeastward compared with the averages;(3) Taiwan Warm Current water could reach 28°N and 30°N in the surface and bottom layer in spring,respectively.It was not observed in the 0—30m layer in summer.It extended to 30.5°N in the northward in the bottom.Hydrographic structures were(1) in spring,the thermocline lay in the center of the Yellow Sea.The thermocline intensity was 0.10—0.40℃/m.The pycnocline lay in the east of Changjiang River estuary and the intensity was 0.20—0.30kg/m4;(2) in summer,the maximum value of the thermocline intensity(2.41℃/m) lay in the northeast of Changjiang River mouth with upper depth at 5.5m and 2.5m thickness.The thermocline intensity in the Yellow Sea was stronger than that in the East China Sea because of remarkable temperature difference in the surface and bottom affected by the Yellow Sea Cold Water;(3) The distribution of pycnocline intensity was almost the same as the thermocline in summer and the maximum value of the pycnocline intensity(1.38kg/m4) lay in the west of 33°N section.The pycnocline upper depth was 5.5m and thickness was 1.5m.Pycnocline intensity along the tongue axes of the Changjiang River Diluted water was 0.30—0.60kg/m4,weakening from west to east.The intensity of thermocline and pycnocline gradually got weaker while the upper depth and thickness got stronger from offshore to the central shelf sea.