Northern Oklahoma CO2 Attribution with Tracers Study (NOCATS) 2010: first deployment of a new mobile laboratory for atmospheric carbon-cycle science
Authors
Bernard D. Zak — Multiple Academic
Mark D. Ivey — Sandia National Laboratories
Fred Helsel — Sandia National Laboratories
Manvendra K. Dubey — Los Alamos National Laboratory
Thom Rahn — Los Alamos National Laboratory
Bradley Flowers — Los Alamos National Laboratory
Hope A. Michelsen — Sandia National Laboratories
Thomas Guilderson — Lawrence Livermore National Laboratory
Ray P. Bambha — Sandia National Laboratories
Paul Schrader — Sandia National Laboratories
Brian LaFranchi — Lawrence Livermore National Laboratory
Category
Field Campaigns
Description
The Atmospheric and Terrestrial Mobile Laboratory was deployed for the first time at the ARM SGP Central Facility to study biogenic and anthropogenic CO2 source attribution.
Anthropogenic sources of carbon dioxide represent a significant portion of the global carbon budget, but partitioning CO2 measurements into their biogenic and anthropogenic sources has been difficult using only measurements of CO2 abundances and those of a small number of additional tracers. An intensive field campaign was conducted in fall 2010 at the ARM SGP Central Facility (IDP1) to measure CO2 and tracers for its sources using a new mobile laboratory. Two trucks carrying over 15 instruments for gases and particles were deployed along with a gas-calibration system. Air was drawn into both trucks from a 10-meter tall mast. All measurements were made either from a common inlet or closely located inlets. Instruments were selected to provide measurements of tracers of both biogenic and anthropogenic sources. High-frequency measurements of abundances of CO2 and its stable isotopologues (13CO2 and C18OO) were made simultaneously with measurements of CO, SO2, NOx, O3, CH4, water vapor isotopologues (H2O, HDO, and H218O), volatile organic compounds, black and organic carbon aerosol, and particle count. Automated flask samplers collected whole-air samples for offline 14C analysis using accelerator mass spectrometry. Redundancy between CO2, CH4, and H2O measurements provided a valuable crosscheck for the calibrations and the measurements. Good agreement between CO2 measurements from four different instruments was attained following careful post-processing and calibrations. Similarly good agreement was demonstrated between four instruments that measured water vapor and two instruments that measured CH4. The agricultural region that surrounds the ARM SGP site had experienced little rainfall prior to the campaign, and land cover and crop growth were minimal during the period in which measurements were made (3 October–9 November 2010). Correlations between various tracers and CO2 provide insight into the different sources, including the anthropogenic component, which includes biomass and fossil fuel combustion.
