Effect of recent observations on Asian CO₂ flux estimates with transport model inversions

S. Maksyutov, T. Machida, H. Mukai, P. K. Patra, T. Nakazawa, G. Inoue, D. Baker, P. Bousquet, L.Bruhwiler, Y-H. Chen, P. Ciais, A. S. Denning, S. Fan, I. Y. Fung, M. Gloor, K. R. Gurney, M. Heimann, K.Higuchi, J. John, R. M.Law, T.Maki, P. Peylin, M. Prather, B. Pak, P. J. Rayner, J. L. Sarmiento, S.Taguchi, T. Takahashi, C-W. Yuen

Tellus, 55B (2), 522-529


We use inverse model to evaluate the effects of recent CO2 observations over Asia on estimates of the Asian regional CO2 sources and sinks. Global CO2 flux distribution is evaluated using several atmospheric transport models, atmospheric CO2 observations and inversion procedure adopted in the basic synthesis inversion by Transcom-3 inverse model intercomparison project (Gurney et al, 2002). In our analysis we include airborne and tower observations in Siberia, continuous monitoring and airborne observations over Japan, the airborne monitoring on regular flights on Tokyo-Sydney route. The inclusion of the data reduces uncertainty of the estimated regional CO2 fluxes for Boreal Asia (Siberia), Temperate Asia, and South-East Asia. The largest effect is observed for emission/sink estimate for Boreal Asia region, where introducing the observations in Siberia reduces the source uncertainty by almost half. It also produces uncertainty reduction for Boreal North America. Addition of the Siberian airborne observations leads to projecting extra sinks on Boreal Asia of 0.2 Pg C/year, and smaller change for Europe. The Tokyo-Sydney observations tend to reduce and further constrain Southeast Asian source.