TY - JOUR
T1 - Quantifying the UK's carbon dioxide flux
T2 - An atmospheric inverse modelling approach using a regional measurement network
AU - White, Emily D.
AU - Rigby, Matthew
AU - Lunt, Mark F.
AU - Luke Smallman, T.
AU - Comyn-Platt, Edward
AU - Manning, Alistair J.
AU - Ganesan, Anita L.
AU - O'Doherty, Simon
AU - Stavert, Ann R.
AU - Stanley, Kieran
AU - Williams, Mathew
AU - Levy, Peter
AU - Ramonet, Michel
AU - Forster, Grant L.
AU - Manning, Andrew C.
AU - Palmer, Paul I.
PY - 2019/4/4
Y1 - 2019/4/4
N2 - We present a method to derive atmospheric-observation-based estimates of carbon dioxide (CO2) fluxes
at the national scale, demonstrated using data from a network of surface
tall-tower sites across the UK and Ireland over the period 2013–2014. The
inversion is carried out using simulations from a Lagrangian chemical
transport model and an innovative hierarchical Bayesian Markov chain Monte
Carlo (MCMC) framework, which addresses some of the traditional problems
faced by inverse modelling studies, such as subjectivity in the
specification of model and prior uncertainties. Biospheric fluxes related to
gross primary productivity and terrestrial ecosystem respiration are solved
separately in the inversion and then combined a posteriori to determine net
ecosystem exchange of CO2. Two different models, Data
Assimilation Linked Ecosystem Carbon (DALEC) and Joint UK Land Environment Simulator (JULES),
provide prior estimates for these fluxes. We carry out separate inversions
to assess the impact of these different priors on the posterior flux
estimates and evaluate the differences between the prior and posterior
estimates in terms of missing model components. The Numerical Atmospheric
dispersion Modelling Environment (NAME) is used to relate fluxes to the
measurements taken across the regional network. Posterior CO2 estimates
from the two inversions agree within estimated uncertainties, despite large
differences in the prior fluxes from the different models. With our method,
averaging results from 2013 and 2014, we find a total annual net biospheric
flux for the UK of 8±79 Tg CO2 yr−1 (DALEC prior) and
64±85 Tg CO2 yr−1 (JULES prior), where negative values represent an
uptake of CO2. These biospheric CO2 estimates show that annual UK
biospheric sources and sinks are roughly in balance. These annual mean
estimates consistently indicate a greater net release of CO2 than the
prior estimates, which show much more pronounced uptake in summer months.
AB - We present a method to derive atmospheric-observation-based estimates of carbon dioxide (CO2) fluxes
at the national scale, demonstrated using data from a network of surface
tall-tower sites across the UK and Ireland over the period 2013–2014. The
inversion is carried out using simulations from a Lagrangian chemical
transport model and an innovative hierarchical Bayesian Markov chain Monte
Carlo (MCMC) framework, which addresses some of the traditional problems
faced by inverse modelling studies, such as subjectivity in the
specification of model and prior uncertainties. Biospheric fluxes related to
gross primary productivity and terrestrial ecosystem respiration are solved
separately in the inversion and then combined a posteriori to determine net
ecosystem exchange of CO2. Two different models, Data
Assimilation Linked Ecosystem Carbon (DALEC) and Joint UK Land Environment Simulator (JULES),
provide prior estimates for these fluxes. We carry out separate inversions
to assess the impact of these different priors on the posterior flux
estimates and evaluate the differences between the prior and posterior
estimates in terms of missing model components. The Numerical Atmospheric
dispersion Modelling Environment (NAME) is used to relate fluxes to the
measurements taken across the regional network. Posterior CO2 estimates
from the two inversions agree within estimated uncertainties, despite large
differences in the prior fluxes from the different models. With our method,
averaging results from 2013 and 2014, we find a total annual net biospheric
flux for the UK of 8±79 Tg CO2 yr−1 (DALEC prior) and
64±85 Tg CO2 yr−1 (JULES prior), where negative values represent an
uptake of CO2. These biospheric CO2 estimates show that annual UK
biospheric sources and sinks are roughly in balance. These annual mean
estimates consistently indicate a greater net release of CO2 than the
prior estimates, which show much more pronounced uptake in summer months.
UR - http://www.scopus.com/inward/record.url?scp=85063879337&partnerID=8YFLogxK
U2 - 10.5194/acp-19-4345-2019
DO - 10.5194/acp-19-4345-2019
M3 - Article (Academic Journal)
SN - 1680-7316
VL - 19
SP - 4345
EP - 4365
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 7
ER -