Measurements and modeling of CO 2 concentration and isotopes to improve process-level understanding of Arctic and boreal carbon cycling. Final Report

• Main Author: Keeling, Ralph F.
• Language: unknown
• Published: 2017
• Subjects: 47 OTHER INSTRUMENTATION; Antarctic; Arctic; Scripps; The Antarctic; Antarc*
• Online Access: http://www.osti.gov/servlets/purl/1395576; https://www.osti.gov/biblio/1395576; https://doi.org/10.2172/1395576

The major goal of this project was to improve understanding of processes that control the exchanges of CO 2 between the atmosphere and the land biosphere on decadal and longer time scales. The approach involves measuring the changes in atmospheric CO 2 concentration and the isotopes of CO 2 ( 13 C/ 12 C and 18 O/ 16 O) at background stations and uses these and other datasets to challenge and improve numerical models of the earth system. The project particularly emphasized the use of these data to improve understanding of changes occurring in boreal and arctic ecosystems over the past 50 years and to seek from these data improved understanding of large-scale processes impacting carbon cycling, such as the responses to warming, CO 2 fertilization, and disturbance. The project also led to advances in the understanding of changes in water-use efficiency of land ecosystems globally based on trends in 13 C/ 12 C. The core element of this project was providing partial support for continuing measurements of CO 2 concentrations and isotopes from the Scripps CO 2 program, initiated by C. D. Keeling in the 1960s. The measurements included analysis of flasks collected at an array of ten stations distributed from the Arctic to the Antarctic. The project also supported modeling studies and interpretive work to help understand the origins of the large ~50% increase in the amplitude of the atmospheric CO 2 cycle detected at high northern latitudes between 1960 and present and to understand the long-term trend in carbon 13 C/ 12 C of CO 2 . The seasonal cycle work was advanced through collaborations with colleagues at MPI Jena and Imperial College