Influence of a Tropical Island Mountain on Solar Radiation, Air Temperature and Vapor Pressure

Abstract

Measured solar radiation, air temperature, and water vapor pressure at 17 stations on the northwest flank of Haleakala, Maui, Hawaii are compared with modeled clear day solar radiation and free atmosphere air temperature and water vapor pressure. The results indicate that the mountain acts as a heat source in summer and heat sink in winter. Surface vapor pressure is close to the free atmosphere value. Also, global solar radiation is reduced to as little as 51% of the clear day value (30% below the open ocean value), the highest solar radiation gradients are in summer, and solar radiation declines with elevation over the study area in both summer and winter except above 1200 m where it increases with elevation in winter.