Scaling an Instantaneous Model of Tundra NEE to the Arctic Landscape

• Published in: Ecosystems
• Main Authors: Loranty, M.M. (Michael M.), Goetz, S.J. (Scott J.), Rastetter, E.B. (Edward B.), Rocha, A.V. (Adrian V.), Shaver, G.R. (Gaius R.), Humphreys, E. (Elyn), Lafleur, P.M. (Peter M.)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: arctic carbon exchange; CO 2 flux; modeling; NEE; tundra; upscaling; Arctic; Tundra
• Online Access: https://ir.library.carleton.ca/pub/5358; https://doi.org/10.1007/s10021-010-9396-4

We scale a model of net ecosystem CO 2 exchange (NEE) for tundra ecosystems and assess model performance using eddy covariance measurements at three tundra sites. The model, initially developed using instantaneous (seconds-minutes) chamber flux (~m 2) observations, independently represents ecosystem respiration (ER) and gross primary production (GPP), and requires only temperature (T), photosynthetic photon flux density (I 0), and leaf area index (L) as inputs. We used a synthetic data set to parameterize the model so that available in situ observations could be used to assess the model. The model was then scaled temporally to daily resolution and spatially to about 1 km 2 resolution, and predicted values of NEE, and associated input variables, were compared to observations obtained from eddy covariance measurements at three flux tower sites over several growing seasons. We compared observations to modeled NEE calculated using T and I 0 measured at the towers, and L derived from MODIS data. Cumulative NEE estimates were within 17 and 11% of instrumentation period and growing season observations, respectively. Predictions improved when one site-year experiencing anomalously dry conditions was excluded