Local Wind Circulation on the Slopes of Mauna Loa

Abstract

Measurements, using a captive balloon system, of the diurnal local winds at the Mauna Loa Observatory showed a 600 m deep upslope flow and 55 m deep downslope flow. Using a model, the mass flux of air in the region of the observatory for a mean 24-hr day showed that six times more air is transported by the upslope flow than by the nocturnal downslope flow. The diural periodicity, wind velocity and mass flux of air in the region of the observatory are controlled by the temperature and radiation flux of the lava surface of the mountain, the strength of the free air flow, and the level and strength of the trade wind inversion. A diurnal pressure gradient between the air enveloping the mountain and the free air was detected as a complement to the diurnal wind regime observed.