Upscaling terrestrial carbon dioxide fluxes in Alaska with satellite remote sensing and support vector regression. Ueyama, M., Ichii, K., Iwata, H., Euskirchen, E., Zona, D., Rocha, A., Harazono, Y., Iwama, C., Nakai, T., & Oechel, W. Journal of Geophysical Research: Biogeosciences, 2013.
abstract   bibtex   
Carbon dioxide (CO < inf > 2 < /inf > ) fluxes from a network of 21 eddy covariance towers were upscaled to estimate the Alaskan CO < inf > 2 < /inf > budget from 2000 to 2011 by combining satellite remote sensing data, disturbance information, and a support vector regression model. Data were compared with the CO < inf > 2 < /inf > budget from an inverse model (CarbonTracker). Observed gross primary productivity (GPP), ecosystem respiration (RE), and net ecosystem exchange (NEE) were each well reproduced by the model on the site scale; root-mean-square errors (RMSEs) for GPP, RE, and NEE were 0.52, 0.23, and 0.48 g C m < sup > -2 < /sup > d < sup > -1 < /sup > , respectively. Landcover classification was the most important input for predicting GPP, whereas visible reflectance index of green ratio was the most important input for predicting RE. During the period of 2000-2011, predicted GPP and RE were 369 ± 22 and 362 ± 12 Tg C yr < sup > -1 < /sup > (mean ± interannual variability) for Alaska, respectively, indicating an approximately neutral CO < inf > 2 < /inf > budget for the decade. CarbonTracker also showed an approximately neutral CO < inf > 2 < /inf > budget during 2000-2011 (growing season RMSE = 14 g C m < sup > -2 < /sup > season < sup > -1 < /sup > ; annual RMSE = 13 g C m < sup > -2 < /sup > yr < sup > -1 < /sup > ). Interannual CO < inf > 2 < /inf > flux variability was positively correlated with air temperature anomalies from June to August, with Alaska acting as a greater CO < inf > 2 < /inf > sink in warmer years. CO < inf > 2 < /inf > flux trends for the decade were clear in disturbed ecosystems; positive trends in GPP and CO < inf > 2 < /inf > sink were observed in areas where vegetation recovered for about 20 years after fire. © 2013. American Geophysical Union. All Rights Reserved.
@article{
 title = {Upscaling terrestrial carbon dioxide fluxes in Alaska with satellite remote sensing and support vector regression},
 type = {article},
 year = {2013},
 identifiers = {[object Object]},
 keywords = {Alaska,Moderate Resolution Imaging Spectroradiometer (MOD,disturbance,eddy covariance,support vector regression},
 volume = {118},
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 created = {2018-04-05T23:20:54.119Z},
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 last_modified = {2018-04-05T23:20:54.119Z},
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 abstract = {Carbon dioxide (CO < inf > 2 < /inf > ) fluxes from a network of 21 eddy covariance towers were upscaled to estimate the Alaskan CO < inf > 2 < /inf >  budget from 2000 to 2011 by combining satellite remote sensing data, disturbance information, and a support vector regression model. Data were compared with the CO < inf > 2 < /inf >  budget from an inverse model (CarbonTracker). Observed gross primary productivity (GPP), ecosystem respiration (RE), and net ecosystem exchange (NEE) were each well reproduced by the model on the site scale; root-mean-square errors (RMSEs) for GPP, RE, and NEE were 0.52, 0.23, and 0.48 g C m < sup > -2 < /sup >  d < sup > -1 < /sup > , respectively. Landcover classification was the most important input for predicting GPP, whereas visible reflectance index of green ratio was the most important input for predicting RE. During the period of 2000-2011, predicted GPP and RE were 369 ± 22 and 362 ± 12 Tg C yr  < sup > -1 < /sup >  (mean ± interannual variability) for Alaska, respectively, indicating an approximately neutral CO < inf > 2 < /inf >  budget for the decade. CarbonTracker also showed an approximately neutral CO < inf > 2 < /inf >  budget during 2000-2011 (growing season RMSE = 14 g C m < sup > -2 < /sup >  season < sup > -1 < /sup > ; annual RMSE = 13 g C m < sup > -2 < /sup >  yr < sup > -1 < /sup > ). Interannual CO < inf > 2 < /inf >  flux variability was positively correlated with air temperature anomalies from June to August, with Alaska acting as a greater CO < inf > 2 < /inf >  sink in warmer years. CO < inf > 2 < /inf >  flux trends for the decade were clear in disturbed ecosystems; positive trends in GPP and CO < inf > 2 < /inf >  sink were observed in areas where vegetation recovered for about 20 years after fire. © 2013. American Geophysical Union. All Rights Reserved.},
 bibtype = {article},
 author = {Ueyama, M. and Ichii, K. and Iwata, H. and Euskirchen, E.S. and Zona, D. and Rocha, A.V. and Harazono, Y. and Iwama, C. and Nakai, T. and Oechel, W.C.},
 journal = {Journal of Geophysical Research: Biogeosciences},
 number = {3}
}

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