Technical Note: A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter R. Zhuravlev1, B. Khattatov2, B. Kiryushov1, and S. Maksyutov3 1Central Aerological Observatory, Dolgoprudny, Russia 2Fusion Numerics International, Boulder, CO, USA 3Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba, Japan
Abstract. In this work we propose an approach to solving a source estimation problem
based on representation of carbon dioxide surface emissions as a linear
combination of a finite number of pre-computed empirical orthogonal
functions (EOFs). We used National Institute for Environmental Studies
(NIES) transport model for computing response functions and Kalman filter
for estimating carbon dioxide emissions. Our approach produces results
similar to these of other models participating in the TransCom3 experiment.
Using the EOFs we can estimate surface fluxes at higher spatial resolution,
while keeping the dimensionality of the problem comparable with that in the
regions approach. This also allows us to avoid potentially artificial sharp
gradients in the fluxes in between pre-defined regions. EOF results
generally match observations more closely given the same error structure as
the traditional method.
Additionally, the proposed approach does not require additional effort of
defining independent self-contained emission regions.
Citation: Zhuravlev, R., Khattatov, B., Kiryushov, B., and Maksyutov, S.: Technical Note: A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter, Atmos. Chem. Phys., 11, 10305-10315, doi:10.5194/acp-11-10305-2011, 2011.