Hawaiin islands. (Credit: Public Domain)
Rainfall patterns in Hawaii have undergone large changes over the years, according to a release from the University of Hawaii at Manoa. While El Niño events would typically cause six months of drought in the Hawaiian Islands, La Niña events would mean rainfall above average. Over time, however, La Niña has given Hawaii more drought instead of additional rains.
Data from 50 National Weather Service rain gauges placed throughout the state showed the shift in La Niña’s behavior. Rain gauge data covered a period from 1956 until 2010. A changepoint analysis showed the shift from excess rain to additional drought occurred in 1983.
Scientists at the university say a combination of changes caused the reduction in La Niña rainfall where there was once an excess. These include a shifting eastern North Pacific subtropical high-pressure system toward the west and a changing subtropical jet stream, which became more elongated in the eastward direction and more intense. Storm-track data indicate that changes in the Hawaiian climate mean conditions are also less conducive to forming Kona low-pressure systems.
Top image: Hawaiin islands. (Credit: Public Domain)