U.S. JGOFS SMP

U.S. JGOFS Synthesis & Modeling Project
Tsung-Hung Peng Jia-Zhong Zhang Yuan-Hui Li
Re-evaluation of Redfield ratios using OACES and DOE/WOCE/JGOFS CO₂ survey data NOAA/DOE OACES, 36 months
PROJECT DESCRIPTION:	The stoichiometric ratios (or Redfield ratios) of P:N:C:O₂ during photosynthesis, respiration, and remineralization processes are fundamental for our understanding biogeochemistry in the ocean. The separation of anthropogenic CO₂ from the large background variability of dissolved inorganic carbon in the ocean in the C* calculation (Gruber et al., 1996) depends on how well we know these stoichiometric ratios. To improve the estimate of anthropogenic CO₂ in the ocean using NOAA/DOE global CO₂ survey data, we must first improve the estimates of Redfield ratios by using the available data including those obtained during the NOAA/DOE global CO₂ survey cruises. We propose to re-evaluate the Redfield ratios based on these new data sets by carrying out the new method of two-end-member and three-end-member mixing models of Li et al. (1998) using the vertical profile data set, as well as using the interpolated data to desired isopycnal surfaces corresponding to various depth as in the traditional two-end-member mixing model. Close collaboration with the Princeton group led by Dr. Key will be maintained. This group focuses on evaluation of Redfield ratios with the isopycnal two-end-member method. Results of our estimates will be compared with theirs and both results will be evaluated to obtain the best possible Redfield ratios. We also propose to analyze NOAA/DOE nutrient data to examine specifically the N/P remineralization ratio and effects of nitrification and denitrification on this ratio in the global oceans.
DATA:	Redfield ratios based on WOCE and GEOSECS sections in Atlantic, Indian, and Pacific Oceans, via SMP Data collection.
PUBLICATIONS:	Li, Y-H and T-H Peng. submitted. Latitudinal change of remineralization ratios in the oceans and its implication for nutrient cycles.
RELATED PROJECTS:	Barber; Chai; Dugdale; Wilkerson; Peng "New and export productivity regulation by Si and Fe in the equatorial Pacific Ocean" Key; Gordon; Sabine; Gruber; Mordy "Determination of the Redfield remineralization ratios based on neutral surface analysis of the new global data set" Sabine; Key; Feely; Millero; Wanninkhof; Kozyr "Synthesis and interpretation of the NOAA/DOE Global CO2 survey data"
INVESTIGATOR INFORMATION:	Dr. Tsung-Hung Peng NOAA/AOML 4301 Rickenbacker Causeway Miami, FL 33149-1026 tel: (305) 361-4399 fax: (305) 361-4392 tsung-hung.peng@noaa.gov http://www.aoml.noaa.gov/ocd/people/peng/ Dr. Jia-Zhong Zhang NOAA/AOML 4301 Rickenbacker Causeway Miami, FL 33149 tel: (305) 361-4397 tel: (305) 361-4392 zhang@aoml.noaa.gov http://www.aoml.noaa.gov/ocd/people/zhang/ Dr. Yuan-Hui Li University of Hawaii 1000 Pope Road Honolulu, HI 96822 tel: (808) 956-6297 yhli@soest.hawaii.edu http://www.soest.hawaii.edu/oceanography/faculty_html/yhli.html