STRUCTURES OF THE MIXED-LAYER AND ESTIMATES OF SEA-SURFACE FLUXES DURING TOGA-COARE IOP .1. STRUCTURES OF THE MIXED-LAYER

The surface and aerological observations made by the Japanese research vessel Hakuho-maru on 11-27 November, 1992 at 0 degrees, 156 degrees E during TOGA-COARE IOP period were used to analyze the evolution and structure of mixed layer over the ocean, and to estimate surface fluxes by using bulk schemes. The Part I of this study is devoted to the problem of the mixed layer. The main finding is that the regional wind field can greatly modify the structure of the mixed layer. For the east trade regime, the mixed layer had a relatively great depth, mostly reaching 800-900 m. Above this level was a dry layer without any significant inversion. For the west wind regime created by four westerly wind bursts, the height of the mixed layer was considerably depressed, or even disappeared. A deep saturation layer was often observed. Two events of the intrusion of the extremely dry air layer greatly enhanced and elevated the mixed layer, up to about 1.5 km. The reason for these events was discussed.