MGGD Research Areas


Atmospheric chemistry and atmosphere-ocean exchange

Nihoa thumbnail photo. The interface between the ocean and atmosphere is a region of particular interest for processes and biogeochemical cycles that couple these reservoirs. Transport of gas and particles in and out of the surface impact both ocean and atmospheric chemistry. One theme of divisional research focuses on anthropogenic and marine aerosols and their significance for global pollution, biogeochemical cycles, atmospheric radiation and climate. Studies of dust deposition to the ocean elucidate the role of aeolian sources of elements such as iron, which is critical for carbon and nutrient cycling in the marine environment. Biological activity is also coupled to the sulfur cycle and flux of gases like DMS into the atmosphere followed by oxidation to condensable species like sulfuric acid. This natural aerosol component influences light propagation in the atmosphere and the nuclei upon which clouds condense. The resulting direct and indirect effects on atmospheric radiation, clouds and climate are areas of active study in the Division.

Division researchers are also active in studies of CO2 flux measurements between the tropical atmospheric boundary layer and surface waters. This research effort is centered around a NOAA-PMEL CO2 Program buoy installed in Kane‘ohe Bay; this buoy collects high resolution time-series data on atmospheric and surface water CO2 partial pressures, and is further instrumented with water property sensors for dissolved oxygen, temperature, salinity, chlorophyll a, turbidity, pH, and particle size distributions. The data from these instruments and a comprehensive sampling program throughout the bay permit the evaluation of the temporal variability in air-sea CO2 fluxes and the mechanisms controlling CO2 fluxes. The Kane‘ohe Bay CO2 measurements comprise one of the longest continuous records of pCO2 in coastal ocean environments. Also, modeling studies dealing with the flux of anthropogenic CO2 from the atmosphere into the ocean complement experimental endeavors. For example, members of the division investigate and forecast the invasion of man-made CO2 into the surface ocean, which leads to ocean acidification with potential consequences for marine calcifying organisms such as corals.

Related studies involve processes and chemical reactions in and on marine aerosol linked to issues that include iron solubility in dust, halogen chemistry, sea-salt production, organic aerosol, black carbon and related atmospheric optics. These activities routinely involve opportunities for theoretical work, laboratory studies and international field studies on land, ships and aircraft. New state-of-the-art instrumentation includes fast ionization mass spectrometers capable of turbulent flux studies and time-of-flight aerosol mass spectrometers capable of continuous single-particle chemical analysis aboard aircraft in real-time.

C130 thumbnail photo.

National Science Foundation's National Center for Atmospheric Research C-130 research aircraft. Researchers from the University of Hawai‘i Department of Oceanography have deployed a number of instrument packages aboard the NSF/NCAR C-130 to study atmospheric trace gases and aerosols. Studies by UH researchers range in focus but have examined processes related to air-sea exchange of gases and aerosols over the remote ocean, and the effects of Asian dust storms on the regional and global climate of East Asia.

DC8 thumbnail photo.

NASA DC-8 research aircraft. Researcher from the University of Hawai‘i Department of Oceanography have deployed a number of instrument packages aboard the NASA DC-8 to study atmospheric trace gases and aerosols. Studies by UH researchers range in focus but have recently examined differences between anthropogenic pollution and smoke from forest fires in Alaska and Canada as well as Mexico City's impact on the weather and climate over the Gulf of Mexico.

Mexico City air pollution thumbnail photo.

A haze of pollution hangs over Mexico City, March 16, 2006. University of Hawaii researchers deployed a suite of instrumentation aboard both the NASA DC-8 and the NSF/NCAR C-130 aircraft in order to characterize the size and optical properties of the aerosols and their impact on the Earth’s climate. These efforts were part of NASA's Intercontinental Chemical Transport Experiment (INTEX-B) and the National Science Foundation's (NSF) Megacities Impact on Regional and Global Environment Experiment (MIRAGE). These experiments were designed to measure pollution from the Mexico City, a megacity of over 22 million people, and its effects regional and global climate as part of a larger international collaboration, the Megacities Initiative: Local and Global Research Observations (MILAGRO).

[ ABOVE ] Researchers from the University of Hawai‘i took this photograph of Nihoa while participating in NASA’s INTEX-B field campaign. INTEX-B was an international, multi-agency field campaign to investigate the effects of anthropogenic emissions on regional and global climate. While operating out of Hawai‘i the NASA DC-8 research aircraft intercepted “rivers” of Asian dust and pollution being transported across the North Pacific to North America.

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