Recent variations in solar radiation at high elevations in Hawai'i
Abstract
Trends in clear-sky and total global solar irradiance for the period of 1988 to 2011 were evaluated based on data obtained from three high elevation climate stations on the island of Maui, Hawai'i. These climate stations, part of the HaleNet climate network, are located on the leeward slope of Haleakalā Volcano and cover a 870 m vertical elevation gradient (2190 - 2990 m) representing points near and above the mean trade wind inversion (2200 m). Solar radiation is affected by variations in aerosol, water vapor, and ozone concentrations, and clouds. Results for the highest elevation station indicate a negligible trend in clear-sky transmission. However, for all sky conditions, including cloudy periods, solar radiation had an upward trend of 0.75 - 0.8 W m -2 per year (3% per decade). This can be explained by decreasing cloudiness over the time period, as indicated by a 38% long-term increase in the frequency of cloud-free days during the period. This trend in solar radiation is consistent with observed declines in rainfall. Together, the reduction in available water and the increase in atmospheric demand associated with higher solar radiation have potentially severe impacts on the high elevation ecosystems of Haleakalā.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMGC21B0899L
- Keywords:
-
- 1650 GLOBAL CHANGE / Solar variability;
- 1807 HYDROLOGY / Climate impacts