Measurements and modeling of CO₂ concentration and isotopes to improve process-level understanding of Arctic and boreal carbon cycling. Final Report

Technical Report · Fri Sep 29 04:00:00 EDT 2017

DOI:https://doi.org/10.2172/1395576· OSTI ID:1395576

Keeling, Ralph F. ^[1]

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1. Univ. of California, San Diego, CA (United States). Scripps Inst. of Oceanography; The Regents of the University of California - San Diego

The major goal of this project was to improve understanding of processes that control the exchanges of CO₂ between the atmosphere and the land biosphere on decadal and longer time scales. The approach involves measuring the changes in atmospheric CO₂ concentration and the isotopes of CO₂ (¹³C/¹²C and ¹⁸O/¹⁶O) 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, CO₂ 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 ¹³C/¹²C. The core element of this project was providing partial support for continuing measurements of CO₂ concentrations and isotopes from the Scripps CO₂ 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 CO₂ cycle detected at high northern latitudes between 1960 and present and to understand the long-term trend in carbon ¹³C/¹²C of CO₂. The seasonal cycle work was advanced through collaborations with colleagues at MPI Jena and Imperial College

• Research Organization: Univ. of California, San Diego, CA (United States). The Regents
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
• Contributing Organization: MPI Jena; Imperial College
• DOE Contract Number: SC0012167
• OSTI ID: 1395576
• Report Number(s): FinalReport; DE-SC--0012167; UCSD 94044A
• Country of Publication: United States
• Language: English

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CO2 concentrations and isotopes