Collaborative Research: Improving Estimated Fluxes of Greenhouse Gases over North America Using a Receptor-Oriented Modeling Framework and In-situ Atmospheric Measurements

Harvard University, Cambridge MA

Investigators

Abstract

The work aims to establish accurate top-down estimates of the surface sources and sinks for important greenhouse gases, including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and carbon monoxide (CO) over North America, and address individual science questions, particularly with regard to the causes of variability on diurnal, seasonal, and interannual timescales that underlie these estimates. Collocated airborne and tower-based measurements of these gases for selected months in the period 2003-2011 will be analyzed using a receptor-oriented Lagrangian particle dispersion model driven by a version of the Weather Research and Forecasting (WRF) model adapted to flux inversion work. The analysis will provide an assessment tool for independent bottom-up emission estimates from existing inventories. The availability of reliable transport fields and a conjoint analysis of the four gases will be critical to the success of the study. Human-induced changes in atmospheric concentrations of greenhouse gases are a major societal concern discussed in the press, in Congress, and by ordinary citizens every day. Currently there is no validation for inventory-based estimates of U.S. and North American contributions to this global problem, and there are indications that these estimates may be in error. The work will decisively improve this situation by providing new assessments based on strong physical and observational constraints. The data, results, and software will be made publicly available during the research, and the principal investigators will engage in public outreach by communicating the results that are pertinent to the public debate on climate change.