Science Data for the article “More Frequent Spaceborne Sampling of XCO2 Improves Detectability of Carbon Cycle Seasonal Transitions in Arctic-Boreal Ecosystems

These datasets are results from modeling experiments to test for the impact of spaceborne sampling of atmospheric CO2 on estimates of land-atmospheric CO2 exchange in the Arctic region. Specifically, we use flux inversion observing system sensitivity experiments (OSSE) to test the relative impact of low frequency sampling from low earth orbit (LEO) vs high frequency sampling from highly elliptical orbit (HEO). LEO sampling is based on the Orbiting Carbon Observatory 2 (OCO-2) mission, which has been in orbit since 2014. HEO sampling is based on the Arctic Fourier Transform Spectrometer Investigation (AURORA) missions, which is a new mission concept introduced in the corresponding paper. Our OSSEs use the JPL-developed Carbon Monitoring System Flux (CMS-Flux) 4-D variational (4D-Var) inversion system (Liu et al 2017) to optimize weekly estimates of net ecosystem exchange (NEE) and ocean fluxes at 4º × 5º. Two OSSEs are conducted, differing in assimilated data: (1) OCO-2 and (2) OCO-2+AURORA. Both OSSEs are run for a period of two years (2015-2016) to examine recovery of the mean seasonal cycle and flux anomalies. Details regarding the model setup can be found in Section 2.3 of the publication associated with this dataset. These files contain global prior, posterior, and true flux for each OSSE from 2015 to 2016 at daily 4º × 5º resolution. Separate files are provided for each year. Prior and True fluxes are the same for each OSSE and denoted in the file as ‘Prior’ and ‘True’, respectively. Posterior fluxes for OCO-2 and OCO-2+AURORA are denoted ‘Posterior_OCO2’ and ‘Posterior_NIR_OCO2’, respectively. Flux variables have dimensions of 365 x 46 x 72, representing days per year, latitude, and longitude. Daily values are based on interpolation from weekly inversion estimates; we thus recommend to average results to weekly or monthly bins. References Liu, J., Bowman, K.W., Schimel, D.S., Parazoo, N.C., Jiang, Z., Lee, M., Bloom, A.A., Wunch, D., Frankenberg, C., Sun, Y. and O’Dell, C.W., 2017. Contrasting carbon cycle responses of the tropical continents to the 2015–2016 El Niño. Science, 358(6360), p.eaam5690.