Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area

Kevin Gurney, Jianming Liang, Risa Patarasuk, Darragh O'Keeffe, Jianhua Huang, Maya Hutchins, Thomas Lauvaux, Jocelyn C. Turnbull, Paul B. Shepson

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The INFLUX experiment has taken multiple approaches to estimate the carbon dioxide (CO 2 ) flux in a domain centered on the city of Indianapolis, Indiana. One approach, Hestia, uses a bottom-up technique relying on a mixture of activity data, fuel statistics, direct flux measurement and modeling algorithms. A second uses a Bayesian atmospheric inverse approach constrained by atmospheric CO 2 measurements and the Hestia emissions estimate as a prior CO 2 flux. The difference in the central estimate of the two approaches comes to 0.94 MtC (an 18.7% difference) over the eight-month period between September 1, 2012 and April 30, 2013, a statistically significant difference at the 2-sigma level. Here we explore possible explanations for this apparent discrepancy in an attempt to reconcile the flux estimates. We focus on two broad categories: 1) biases in the largest of bottom-up flux contributions and 2) missing CO 2 sources. Though there is some evidence for small biases in the Hestia fossil fuel carbon dioxide (FFCO 2 ) flux estimate as an explanation for the calculated difference, we find more support for missing CO 2 fluxes, with biological respiration the largest of these. Incorporation of these differences bring the Hestia bottom-up and the INFLUX inversion flux estimates into statistical agreement and are additionally consistent with wintertime measurements of atmospheric 14 CO 2 . We conclude that comparison of bottom-up and top-down approaches must consider all flux contributions and highlight the important contribution to urban carbon budgets of animal and biotic respiration. Incorporation of missing CO 2 fluxes reconciles the bottom-up and inverse-based approach in the INFLUX domain.

Original languageEnglish (US)
Article number44
JournalElementa
Volume5
DOIs
StatePublished - Jan 1 2017
Externally publishedYes

Fingerprint

urban area
Fluxes
respiration
carbon dioxide
top-down approach
carbon budget
flux measurement
fossil fuel
Carbon dioxide
animal
Fossil fuels
modeling
Animals
experiment
Statistics
Carbon
incorporation

Keywords

  • Carbon flux
  • Carbon footprint
  • Fossil fuel CO2

ASJC Scopus subject areas

  • Oceanography
  • Environmental Engineering
  • Ecology
  • Geotechnical Engineering and Engineering Geology
  • Geology
  • Atmospheric Science

Cite this

Gurney, K., Liang, J., Patarasuk, R., O'Keeffe, D., Huang, J., Hutchins, M., ... Shepson, P. B. (2017). Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area Elementa, 5, [44]. https://doi.org/10.1525/elementa.137

Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area . / Gurney, Kevin; Liang, Jianming; Patarasuk, Risa; O'Keeffe, Darragh; Huang, Jianhua; Hutchins, Maya; Lauvaux, Thomas; Turnbull, Jocelyn C.; Shepson, Paul B.

In: Elementa, Vol. 5, 44, 01.01.2017.

Research output: Contribution to journalArticle

Gurney, K, Liang, J, Patarasuk, R, O'Keeffe, D, Huang, J, Hutchins, M, Lauvaux, T, Turnbull, JC & Shepson, PB 2017, ' Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area ', Elementa, vol. 5, 44. https://doi.org/10.1525/elementa.137
Gurney, Kevin ; Liang, Jianming ; Patarasuk, Risa ; O'Keeffe, Darragh ; Huang, Jianhua ; Hutchins, Maya ; Lauvaux, Thomas ; Turnbull, Jocelyn C. ; Shepson, Paul B. / Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area In: Elementa. 2017 ; Vol. 5.
@article{ee4919acf4e1415280bd9638192c035f,
title = "Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area",
abstract = "The INFLUX experiment has taken multiple approaches to estimate the carbon dioxide (CO 2 ) flux in a domain centered on the city of Indianapolis, Indiana. One approach, Hestia, uses a bottom-up technique relying on a mixture of activity data, fuel statistics, direct flux measurement and modeling algorithms. A second uses a Bayesian atmospheric inverse approach constrained by atmospheric CO 2 measurements and the Hestia emissions estimate as a prior CO 2 flux. The difference in the central estimate of the two approaches comes to 0.94 MtC (an 18.7{\%} difference) over the eight-month period between September 1, 2012 and April 30, 2013, a statistically significant difference at the 2-sigma level. Here we explore possible explanations for this apparent discrepancy in an attempt to reconcile the flux estimates. We focus on two broad categories: 1) biases in the largest of bottom-up flux contributions and 2) missing CO 2 sources. Though there is some evidence for small biases in the Hestia fossil fuel carbon dioxide (FFCO 2 ) flux estimate as an explanation for the calculated difference, we find more support for missing CO 2 fluxes, with biological respiration the largest of these. Incorporation of these differences bring the Hestia bottom-up and the INFLUX inversion flux estimates into statistical agreement and are additionally consistent with wintertime measurements of atmospheric 14 CO 2 . We conclude that comparison of bottom-up and top-down approaches must consider all flux contributions and highlight the important contribution to urban carbon budgets of animal and biotic respiration. Incorporation of missing CO 2 fluxes reconciles the bottom-up and inverse-based approach in the INFLUX domain.",
keywords = "Carbon flux, Carbon footprint, Fossil fuel CO2",
author = "Kevin Gurney and Jianming Liang and Risa Patarasuk and Darragh O'Keeffe and Jianhua Huang and Maya Hutchins and Thomas Lauvaux and Turnbull, {Jocelyn C.} and Shepson, {Paul B.}",
year = "2017",
month = "1",
day = "1",
doi = "10.1525/elementa.137",
language = "English (US)",
volume = "5",
journal = "Elementa",
issn = "2325-1026",
publisher = "BioOne",

}

TY - JOUR

T1 - Reconciling the differences between a bottom-up and inverse-estimated FFCO 2 emissions estimate in a large US urban area

AU - Gurney, Kevin

AU - Liang, Jianming

AU - Patarasuk, Risa

AU - O'Keeffe, Darragh

AU - Huang, Jianhua

AU - Hutchins, Maya

AU - Lauvaux, Thomas

AU - Turnbull, Jocelyn C.

AU - Shepson, Paul B.

PY - 2017/1/1

Y1 - 2017/1/1

N2 - The INFLUX experiment has taken multiple approaches to estimate the carbon dioxide (CO 2 ) flux in a domain centered on the city of Indianapolis, Indiana. One approach, Hestia, uses a bottom-up technique relying on a mixture of activity data, fuel statistics, direct flux measurement and modeling algorithms. A second uses a Bayesian atmospheric inverse approach constrained by atmospheric CO 2 measurements and the Hestia emissions estimate as a prior CO 2 flux. The difference in the central estimate of the two approaches comes to 0.94 MtC (an 18.7% difference) over the eight-month period between September 1, 2012 and April 30, 2013, a statistically significant difference at the 2-sigma level. Here we explore possible explanations for this apparent discrepancy in an attempt to reconcile the flux estimates. We focus on two broad categories: 1) biases in the largest of bottom-up flux contributions and 2) missing CO 2 sources. Though there is some evidence for small biases in the Hestia fossil fuel carbon dioxide (FFCO 2 ) flux estimate as an explanation for the calculated difference, we find more support for missing CO 2 fluxes, with biological respiration the largest of these. Incorporation of these differences bring the Hestia bottom-up and the INFLUX inversion flux estimates into statistical agreement and are additionally consistent with wintertime measurements of atmospheric 14 CO 2 . We conclude that comparison of bottom-up and top-down approaches must consider all flux contributions and highlight the important contribution to urban carbon budgets of animal and biotic respiration. Incorporation of missing CO 2 fluxes reconciles the bottom-up and inverse-based approach in the INFLUX domain.

AB - The INFLUX experiment has taken multiple approaches to estimate the carbon dioxide (CO 2 ) flux in a domain centered on the city of Indianapolis, Indiana. One approach, Hestia, uses a bottom-up technique relying on a mixture of activity data, fuel statistics, direct flux measurement and modeling algorithms. A second uses a Bayesian atmospheric inverse approach constrained by atmospheric CO 2 measurements and the Hestia emissions estimate as a prior CO 2 flux. The difference in the central estimate of the two approaches comes to 0.94 MtC (an 18.7% difference) over the eight-month period between September 1, 2012 and April 30, 2013, a statistically significant difference at the 2-sigma level. Here we explore possible explanations for this apparent discrepancy in an attempt to reconcile the flux estimates. We focus on two broad categories: 1) biases in the largest of bottom-up flux contributions and 2) missing CO 2 sources. Though there is some evidence for small biases in the Hestia fossil fuel carbon dioxide (FFCO 2 ) flux estimate as an explanation for the calculated difference, we find more support for missing CO 2 fluxes, with biological respiration the largest of these. Incorporation of these differences bring the Hestia bottom-up and the INFLUX inversion flux estimates into statistical agreement and are additionally consistent with wintertime measurements of atmospheric 14 CO 2 . We conclude that comparison of bottom-up and top-down approaches must consider all flux contributions and highlight the important contribution to urban carbon budgets of animal and biotic respiration. Incorporation of missing CO 2 fluxes reconciles the bottom-up and inverse-based approach in the INFLUX domain.

KW - Carbon flux

KW - Carbon footprint

KW - Fossil fuel CO2

UR - http://www.scopus.com/inward/record.url?scp=85061793551&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85061793551&partnerID=8YFLogxK

U2 - 10.1525/elementa.137

DO - 10.1525/elementa.137

M3 - Article

AN - SCOPUS:85061793551

VL - 5

JO - Elementa

JF - Elementa

SN - 2325-1026

M1 - 44

ER -