TY - JOUR
T1 - Open-path eddy covariance measurements of ammonia fluxes from a beef cattle feedlot
AU - Sun, Kang
AU - Tao, Lei
AU - Miller, David J.
AU - Zondlo, Mark Andrew
AU - Shonkwiler, Kira B.
AU - Nash, Christina
AU - Ham, Jay M.
N1 - Funding Information:
The authors acknowledge Prathap Ramamurthy, Dan Li, Qi Li, Josh DiGangi, Anthony O’Brien, Minghui Diao, Da Pan, Levi Golston, and Elie Bou-Zeid at Princeton University for helpful discussions. Special thanks to the research group of Azer Yalin at Colorado State University for the use of laboratory space. The feedlot work was supported by the Center for Mid-Infrared Technologies for Health and the Environment (MIRTHE) under National Science Foundation Grant No. EEC-0540832. Kang Sun acknowledges support by a NASA Earth and Space Science Fellowship (NN12AN64H). Additional support was provided by USEPA grant R834551. Its contents are solely the responsibility of the grantee and do not necessarily represent the official views of the USEPA. Further, USEPA does not endorse the purchase of any commercial products or services mentioned in the publication. This work was partially supported by the USDA National Institute of Food and Agriculture project 2012-03407. This work was also partially supported by grant number 2012-67021-19978 from the USDA/NSF National Robotics Initiative. We thank two anonymous reviewers for very helpful feedback and comments on the manuscript.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - Eddy covariance (EC) measurements of NH3 fluxes from a cattle feedlot were made with a high-precision, fast-response (20Hz) open-path laser-based sensor. The sensor employed a continuous wave, quantum cascade (QC) laser and targeted an isolated absorption feature of NH3 at 9.06μm. It was deployed on a 5-m tall flux tower beside a 22,000-animal cattle feedlot in Colorado, USA for two weeks. Sensible heat, latent heat, CO2, and CH4 EC fluxes were measured concurrently on the tower. The open-path NH3 sensor showed a comparable time response to well-established commercial open-path sensors for CO2 and H2O. The average high-frequency flux loss over the measurement period was 6.6%, mainly resulting from sample path averaging. The sensor showed significant improvement over NH3 EC fluxes measured by closed-path sensors. The measured NH3 EC fluxes were well-correlated with latent heat EC fluxes. During the measurement period, the average daily NH3 EC flux was 31.7kgha-1d-1. The flux-variance relationship was used to further validate the performance of the NH3 EC flux measurement. A 1σ detection limit of 1.3±0.5ngm-2s-1 for NH3 fluxes measured in 30-min intervals was achieved in this field test. This suite of measurements enabled the evaluation of livestock NH3 emissions at unprecedented temporal resolution and accuracy in the context of other important agricultural trace gases.
AB - Eddy covariance (EC) measurements of NH3 fluxes from a cattle feedlot were made with a high-precision, fast-response (20Hz) open-path laser-based sensor. The sensor employed a continuous wave, quantum cascade (QC) laser and targeted an isolated absorption feature of NH3 at 9.06μm. It was deployed on a 5-m tall flux tower beside a 22,000-animal cattle feedlot in Colorado, USA for two weeks. Sensible heat, latent heat, CO2, and CH4 EC fluxes were measured concurrently on the tower. The open-path NH3 sensor showed a comparable time response to well-established commercial open-path sensors for CO2 and H2O. The average high-frequency flux loss over the measurement period was 6.6%, mainly resulting from sample path averaging. The sensor showed significant improvement over NH3 EC fluxes measured by closed-path sensors. The measured NH3 EC fluxes were well-correlated with latent heat EC fluxes. During the measurement period, the average daily NH3 EC flux was 31.7kgha-1d-1. The flux-variance relationship was used to further validate the performance of the NH3 EC flux measurement. A 1σ detection limit of 1.3±0.5ngm-2s-1 for NH3 fluxes measured in 30-min intervals was achieved in this field test. This suite of measurements enabled the evaluation of livestock NH3 emissions at unprecedented temporal resolution and accuracy in the context of other important agricultural trace gases.
KW - Cattle feedlot
KW - NH<inf>3</inf> flux
KW - Open-path eddy covariance
KW - Quantum cascade laser
UR - http://www.scopus.com/inward/record.url?scp=84937206371&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84937206371&partnerID=8YFLogxK
U2 - 10.1016/j.agrformet.2015.06.007
DO - 10.1016/j.agrformet.2015.06.007
M3 - Article
AN - SCOPUS:84937206371
SN - 0168-1923
VL - 213
SP - 193
EP - 202
JO - Agricultural and Forest Meteorology
JF - Agricultural and Forest Meteorology
ER -