Naturally occurring surfactants are found at the surface of much of the ocean. These substances have a critical impact on the exchange of gases between the ocean and the atmosphere and may compose the bulk of the organic mass coming from the ocean to form organic atmospheric aerosols. It has been difficult to study the concentration and dynamics of these substances because there is not a noninvasive method to measure them without altering the ambient wave and turbulence characteristics, which are intricately linked with the surfactant concentration. This EAGER project will develop a new method and demonstrate its feasibility for wavy water surfaces, which should enable many interesting studies both in the laboratory, and in the ocean if the instrument can be sufficiently hardened.
The objective of this research is to demonstrate that vibrational sum-frequency spectroscopy (VSFS) can be used as a non-invasive in situ method for direct measurement of surfactant concentrations on wind-roughened water surfaces. This research will use the synthetic jet array tank (SJAT) at the University of Washington. Surfactant concentrations will be measured in situ using the nonlinear laser spectroscopic method of vibrational sum-frequency spectroscopy. The SJAT is a unique facility constructed as part of prior NSF-sponsored work.
The study will provide a novel approach to measurement of surfactants on air-water interfaces. If successful, VSFS will provide detailed understanding on the mechanisms by which surface active material affect air-water gas transfer processes and are transported to the atmosphere to form organic aerosols. The PI has an extensive record of significant contributions in this area. The laboratory experiments are essential for progress towards the long-term goal of developing a VSFS methodology that could be used for in situ oceanographic measurements of naturally occurring surfactants.
Broader Impacts : The project will promote teaching, training, and learning through participation of a summer undergraduate research intern arranged through the Washington Space Grant Summer Undergraduate Research Program (SURP).
The project will enhance infrastructure for research and education by: 1. Developing a hands-on demonstration on air-water exchange processes that will be presented yearly at the Science Expo sponsored by the Pacific Science Center 2. Continuing to present a seminar in a question and answer discussion format dealing with the role of the oceans in global climate change, with emphasis on air-sea exchange processes, presented to groups of 20-30 students for grades 8-12 (with level of sophistication matched to the audience) 3.Continuing to participate in the University of Washington's "Math Day" outreach program for high schools in Washington State by presenting lectures on the use of mathematics in oceanography to approximately 120 students and high school teachers per year
The project will broaden the participation of underrepresented groups by: 1. Developing a standard tour and demonstration of the synthetic jet array tank facility including for interested schools and classes 2. Recruiting summer research interns from local community colleges with high populations of students of color through the NASA-sponsored Washington Space Grant SURP
