Summer 2007 [Team Website]

Mentor: Dr. Jinchun Yuan

A Multiple Linear Regression of pCO2 against Sea SurfaceTemperature, Salinity, and Chlorophill a at Station ALOHA and its Potential for Estimate pCO2 from Satellite Data

Abstract

Ocean is one of the major reservoirs of carbon and can be a major sink of anthropogenic carbon dioxide. Together with pH, alkalinity, and total dissolved inorganic carbon( DIC), partial pressure of carbon dioxide (pCO2) is one of the four essential parameters for determining aquatic CO2 system. These four CO2 parameters are interrelated through chemical equilibrium and the determination of any two is sufficient for calculating the other two parameters. Ship-based oceanographic research cruise, that is expensive to operate and inefficient to provide global coverage, has long been the main source of data for characterizing oceanic CO2 system. Recently, Lohrenz and Cai (2006) conducted a field study of partial pressure of carbon dioxide, temperature, salinity, and Chlorophill a in surface waters of the Northern Gulf of Mexico and developed a correlation method for estimating carbon dioxide distribution from the Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data. Although it showed great potential, the correlation is based on field data with a small temperature variation and atypical salinity, and it is not clear whether it can be applied elsewhere. Here, we propose to extend the applicability of the method by conducting a data analysis study of field observations conducted at station ALOHA( A Long-term Oligotrophic Habitat Assessement; 22° 45'N, 158° 00'W)

Specifically, we will: (1) Obtain field data of alkalinity, DIC, temperature, salinity, and Chlorophill a determined at station ALOHA in the last two decades; (2) Calculate pCO2 from alkalinity and DIC; (3) Apply the correlation method to test the applicability of the method in the central North Pacific Ocean; (4) Apply the correlation method and predict the distributions of partial pressure and air-sea fluxes of carbon dioxide in the central Pacific Ocean from MODIS data.