University of Hawai'i University Relations Media & Publications Honolulu, HI 96822	(808) 956-8856 Telephone (808) 956-3441 Facsimile ur@hawaii.edu E-Mail
FOR IMMEDIATE RELEASE	July 18, 1997
Contact: Cheryl Ernst, (808) 956-5941

LITTLE GREEN BEAMS UH Scientists Responsible for Light Beams Near Rabbit Island Green light emanating from the Makai Pier on the Windward side of O'ahu at night has caused a bit of a stir lately, with the nervous and curious even calling emergency numbers to report unusual activity. The sudden attention caught University of Hawai'i scientists a bit by surprise. After all, they've been aiming their scientific laser across the water at least a couple nights a week since December in a perfectly innocent study of coastal haze. The haze is the result of airborne particles, or aerosols, that reflect light. Particulates can come from natural sources (such as volcanic "vog") or pollution. They change as they pass over the ocean in what is called the boundary layer&emdash;the portion of the atmosphere that is bounded by the ocean surface below and the clouds above and is subject to the mist of sea spray and salt. UH researchers are studying physical, chemical and optical properties in the boundary layer, with a particular focus on aerosol and humidity as a function of atmospheric conditions. High winds and breaking ocean waves produce plumes of sea salt aerosol and affect visibility. Another topic of interest is the sulfur cycle. Sulfur dioxide from pollution and natural sources transforms into droplets of sulfuric acid, which is further modified as they pass over the ocean. Investigation of coastal haze in the boundary layer off O'ahu should generate data of interest in several areas, including health concerns related to vog and urban coastal pollution, the possible role of sulfur particulates in climate change and implications for properties such as visibility and transmission in optical communication. Instrumentation being used in the study was developing by UH scientists under federal grants. Similar to radar, this "lidar" (for light detection and ranging) directs a laser beam, usually green, into the haze. The affect is something like headlights reflecting off fog and can be observed from the highway and pullouts near Makapu'u. When the beam is directed toward Rabbit Island, the reflected light appears to originate there. The beam is occasionally directed overhead, but is turned off when airplanes are in the area. Readings will be taken through the end of September under the current grant, but could continue for another three years if additional funding is received. To arrange for filming or photography, contact Cheryl Ernst at 956-5941 during the week or 261-1361 on the weekend.