Investigation of the Spatial Heterogeneity and Fluxes of Carbon Dioxide Using a Lagrangian Approach From an Aircraft

Aircraft measurements of CO2, sensible heat, and 3-dimensional winds were conducted as part of the Mid- Continent Intensive campaign of the North American Carbon Program, in June of 2007. These "top-down" atmospheric budget observations were used to assess the horizontal and vertical spatial heterogeneity of CO2 concentrations throughout the boundary layer and the lower free troposphere and to compare with observed "bottom-up" budgets as measured by a network of tall towers surrounding a predominately agricultural landscape in Iowa (USA). Regional aircraft-based CO2 fluxes were estimated using a Lagrangian approach by measuring a net drawdown of mixed-layer averages of CO2 concentration from mid-morning to late afternoon due to primary productivity in the region. The results from over 53hrs of flights spanning 11 days in June 2007 are presented. A statistical analysis of the spatial variance of CO2 mixing ratios and the application to ecosystem exchange and transport models are discussed.