TURBULENT FLUX MEASUREMENTS AND ENERGY BUDGET ANALYSIS OVER THE EQUATORIAL PACIFIC DURING TOGA-COARE IOP

Turbulent flux measurements were carried out on board the R/V Hakuhoma ru during TOGA-COARE IOP in Nov., 1999. She stayed at the station of 1 56 degrees E on the equator, north of the Intensive Flux Array (IFA) o f COARE region for more than 2 weeks (Asai, 1993). Turbulent fluxes we re evaluated by the eddy correlation method, including ship motion cor rections for wind velocity fluctuations. The weather situation was rel atively calm for most of the period. Convective activity developed in the latter half of the period with occasional showers. It was found th at heat fluxes from the sea surface were about 14 Wm(-2) and 88 Wm(-2) for sensible and latent heat fluxes, respectively, as mean values of the period when Brook's correction was accepted. However they increase d to almost double when a gust front developed from the precipitating cumulus as a downdraft. Bulk transfer coefficients were estimated from eddy fluxes and bulk meteorological values. The average values of C-H = 1.32 x 10(-3) and C-E = 1.16 x 10(-3) were evaluated. The wind spee d dependencies of the coefficients were investigated and increases in the low wind speed region were observed, which supports the previous p rediction. The surface energy budget was investigated based on radiati on and turbulent flux measurements. The net heat flux into the water w as estimated to be about 68 Wm(-2) in this period. The present data of eddy correlation measurements are considered to be one of the sea tru th standards, as well as the ones from the R/V Moana Wave, Franklin an d Natsushima.