Interannual variability of solar irradiance over the Amazon Basin including the 1982-83 El Nino year

Abstract

Surface solar irradiance (SW↓) was derived over the extended Amazon Basin using AVHRR observations from polar-orbiting satellites during four July months (1983-1986). It was demonstrated that it is now possible to derive long-term surface SW↓, which can be useful in climate studies, and that the accuracy of the derived fields is sufficient to detect interannual differences that can exceed at times 70 W m-2. The variability of the daily totals of SW↓ from the monthly means was similar during three of the four years investigated, yet, during the El Nino year of 1982-83, north of 10°N such varability increased drastically. This increase could be attributed to a changed pattern of convective activity as a result of higher SST off the coast of Peru. -from Authors