Solar Radiation and Energy Flux Change on Manus Island, Papua New Guinea

Abstract

We observed global solar radiation changes through two months during the IOP of TOGA-COARE from 19 November 1992 to 19 January 1993 on Manus Island, Papua New Guinea, in the western tropical Pacific. The whole observation period was divided into four stages through consideration of the daily variations of solar radiation. Significant features of each period were also presented in terms of the activity of cloud convection derived from T_BB data of GMS and zonal wind changes observed by a wind profiler. Surface winds were changeable throughout the observation period; however, an episodic strong westerly wind was observed from the end of December to early January. The most active stage of cloud convection, which was characterized by a decrease of solar radiation in the afternoon, was observed before the westerly wind episode. Morning convection was, however, prominent during the period of the strong westerly wind. A diurnal change of solar radiation was also compared with the change of latent and sensible heat fluxes obtained using the eddy correlation method. Energy fluxes on a ground surface indicated a quick response within about 30 minutes to solar radiation change. Latent and sensible heat fluxes were almost zero at nighttime, but the maximum value of latent and sensible heat fluxes in the daytime were about 270 and 200Wm^-2, respectively.