Dennison, Philip (Phil): University of Utah (Project Lead)
Project Funding:
2017 - 2019
NRA: 2016 NASA: Utilization of Airborne Visible/Infrared Imaging Spectrometer- Next Generation Data from an Airborne Campaign in India-AVRSNG
Funded by NASA, Other US Funding:
Abstract:
Anthropogenic emissions of carbon dioxide (CO2) and methane (CH4) have resulted in positive radiative forcing and increased global temperature. For both atmospheric trace gases, point source emissions represent an important contribution to total emissions. A small number of point sources contribute a large percentage of point source emissions, with EPA data pointing to less than 1.5% of facilities being responsible for over a third of total reported point source emissions in the US. Unintended CH4 emissions, known as fugitive emissions, have also been shown to be regionally significant sources. Detecting and quantifying point source emissions is critically important for reducing anthropogenic greenhouse gas emissions, but current and planned satellite missions for retrieving column CO2 and CH4 concentrations are not capable of resolving point source emitters. Recent work has demonstrated that Airborne Visible Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG) data are capable of detecting trace gas plumes and even estimating emission rates. Matched filter algorithms developed for trace gas plume detection have shown some success, but they ignore spatial structure in background reflectance and in the plume itself. Taking this spatial structure into account will reduce false positive plume detections and improve sensitivity to trace gas absorption features in the shortwave infrared. The primary objective of the proposed research is to develop new iterative algorithms for CO2 and CH4 plume detection in AVIRISNG data using data collected during the India campaign. These algorithms will explicitly take advantage of spatial correlation in trace gas concentrations within plumes to improve detection, applying methods developed within the field of biomedical image reconstruction. The algorithms will rely on maximum a posteriori (MAP) parametric estimation and Markov random field modeling to estimate trace gas mixing ratio length, the product of concentration and path length. Template spectra required for detection will be generated by radiative transfer modeling. A new iterative algorithm will be applied to the entirety of AVIRIS-NG data collected during the India campaign. Likely emitting point sources included in the AVIRIS-NG India images include power plants, refineries, and industrial facilities. Additionally, we will apply the new iterative algorithm to US AVIRIS-NG images collected over similar point sources plus oil and natural gas fields. We will use the combination of Indian and US data to compare the mixing ratio length and spatial characteristics of detected trace gas plumes in each country. We will also produce a benchmark dataset of AVIRIS-NG images designed to catalyze future algorithm improvements. This set of images collected from both India and the US will contain a range of plume strengths and spatial configurations, and will be made available to the global research community for testing and comparing new plume detection algorithms. The proposed research will advance efforts to identify and quantify global point source emissions. Improved plume detection and reduction of false positives will assist quantitative trace gas retrieval algorithms like iterative maximum a posteriori differential optical absorption spectroscopy (IMAP-DOAS). Characterization of plumes found in AVIRIS-NG data acquired in both countries may reveal how infrastructure impacts point source emissions, informing future global point source mapping efforts that could be realized with a satellite imaging spectrometer mission. Our research closely aligns with the objectives of NASA’s Carbon Cycle and Ecosystems Focus Area, the US Carbon Cycle Science Plan, and the pre-Decadal Survey workshop on Carbon-Climate System science.
Publications:
Thorpe, A. K., Frankenberg, C., Thompson, D. R., Duren, R. M., Aubrey, A. D., Bue, B. D., Green, R. O., Gerilowski, K., Krings, T., Borchardt, J., Kort, E. A., Sweeney, C., Conley, S., Roberts, D. A., Dennison, P. E. 2017. Airborne DOAS retrievals of methane, carbon dioxide, and water vapor concentrations at high spatial resolution: application to AVIRIS-NG. Atmospheric Measurement Techniques. 10(10), 3833-3850. DOI: 10.5194/amt-10-3833-2017
More details may be found in the following project profile(s):