A53L-3377:
Improving and Assessing Aircraft-based Greenhouse Gas Emission Fluxes as Part of INFLUX.
Friday, 19 December 2014
Alexie M. F. Heimburger1, Maria Obiminda L Cambaliza1, Paul B Shepson2, Zuofeng Shang2, Brian H Stirm2, Robert Michael Hardesty3, Alan Brewer4, Kenneth J Davis5 and Thomas Lauvaux6, (1)Purdue University, West Lafayette, IN, United States, (2)Purdue Univ, West Lafayette, IN, United States, (3)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (4)NOAA/ESRL/CSD, Boulder, CO, United States, (5)Penn State Univ, University Park, PA, United States, (6)Pennsylvania State University Main Campus, University Park, PA, United States
Abstract:
The goal of the Indianapolis Flux Experiment (INFLUX) is to develop, asses and improve top-down and bottom-up approaches for quantifying urban greenhouse gas emissions. We have been quantifying the emission rates for both CO2 and CH4 from the city of Indianapolis, using an aircraft-based mass balance approach, since 2008. Here we discuss a summary of measurements to date, focusing on improvements to the mass balance experiment design, and recent efforts to improve and assess the method precision. To determine the method precision, we designed a new flight experiment based on multiple-downwind transects. We fly at two 5km-apart downwind distances from the city, each distance comprising multiple transects at different altitudes spanning the depth of the boundary layer, and then calculate the difference in the two flux determinations as a measure of precision. We will also discuss the results of multiple experiments for assumed constant total emission rate conditions, as a means to obtain an improved standard deviation of the mean determination. Finally, we will discuss efforts to conduct a rigorous error propagation for the aircraft mass balance experiment, and compare the results to the observed experimental precision. Our goal is to dramatically improve the method overall uncertainty from the previous estimate of 50%.
