Cloud water interception in Hawai‘i – Part 2: Mapping current and future exchange of water between clouds and vegetation in Hawaiʻi’s mountains

Clouds often come in contact with vegetation (often named fogs) within a certain elevation range on Hawaiʻi’s mountains. Propelled by strong winds, cloud droplets are driven onto the stems and leaves of plants where they are deposited. Some of the water that accumulates on the plants in this way drips to the ground, adding additional water over and above the water supplied by rainfall. Prior observations show that the amount of cloud water intercepted by vegetation is substantial, but also quite variable from place to place. It is, therefore, important to create a map for the complex spatial patterns of cloud water interception (CWI) in Hawaiʻi. In this project, we proposed to create the CWI map at 0.8-km resolution based on the 20-year present-day climate simulations using the Hawai’i Regional Climate Model (HRCM) equipped with a well-tested fog deposition scheme. The map was intended to be verified against measurements at five representative observational sites across the Hawaiian Islands. We also aimed to assess the projected changes in the CWI patterns in Hawai’i by the later 21st century under both weak and strong global warming scenarios.

View across high-elevation slopes with clouds intruding between foreground bushes and background volcanic crests.
Fog brushes the high elevation Haleakala forests, contribution cloudwater to the hydrologic system. (Photo:TGiambelluca)




Yuqing Wang
Professor of Meteorology/IPRC, UH Mānoa