Data Analysis and Instrument Performance Assessment for Regional Carbon Flux Estimates

The initial test and science flights of the Sherpa airborne system for direct greenhouse gas (GHG) flux measurements were completed in September 2016. Here we plan to continue work on the flux data analysis and to assess the performance of the system instrumentation under support from the IRAD. The objectives are to produce science-quality flux data products including quantitative uncertainty bounds, to evaluate instrument performance with respect to flux measurement requirements, and to document lessons learned from the first flight series.  

The overall objective of the activity is to assemble a NASA airborne system for eddy covariance measurements of regional GHG fluxes and to use this system to obtain GHG flux data for a range of ecosystem states and land use regions. Such measurements are needed to evaluate CO₂ and CH₄ top-down and bottom-up source and sink estimates. These observations will validate top-level OCO-2 products and those from other space-based GHG missions, while testing and improving parameterization of biogeophysical flux models. In-flight demonstration of the flux measurement is necessary to mature the system TRL.

The innovative elements in the proposed work are: 1) to modify commercial off-the-shelf instrumentation into a new capacity for direct airborne flux measurement and 2) to enable development of a GHG flux measurement facility that will provide a new tool for NASA science. Although the eddy covariance technique is well established, historically NASA has had limited involvement in these measurements. The specific objective of this proposal is to document and further improve the performance of the airborne flux measurement system through post-flight analysis, as needed for securing future support.