Evaluating the agreement between measurements and models of net ecosystem exchange at different times and timescales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis

Abstract

Earth system processes exhibit complex patterns across time, as do the models that seek to replicate these processes. Model output may or may not be significantly related to observations at different times and on different frequencies. Conventional model diagnostics provide an aggregate view of model-data agreement, but usually do not identify the time and frequency patterns of model-data disagreement, leaving unclear the steps required to improve model response to environmental drivers that vary on characteristic frequencies. Wavelet coherence can quantify the times and timescales at which two time series, for example time series of models and measurements, are significantly different. We applied wavelet coherence to interpret the predictions of 20 ecosystem models from the North American Carbon Program (NACP) Site-Level Interim Synthesis when confronted with eddy-covariance-measured net ecosystem exchange (NEE) from 10 ecosystems with multiple years of available data.

Citation

Stoy, P.C.; Dietze, M.C.; Richardson, A.D.; Vargas, R.; Barr, A.G.; Anderson, R.S.; Arain, M.A.; Baker, I.T.; Black, T.A.; Chen, J.M.; Cook, R.B.; Gough, C.M.; Grant, R.F.; Hollinger, D.Y.; Izaurralde, R.C.; Kucharik, C.J.; Lafleur, P.; Law, B.E.; Liu, S.; Lokupitiya, E.; Luo, Y.; Munger, J. W.; Peng, C.; Poulter, B.; Price, D.T.; Ricciuto, D. M.; Riley, W. J.; Sahoo, A. K.; Schaefer, K.; Schwalm, C.R.; Tian, H.; Verbeeck, H.; Weng, E. 2013. Evaluating the agreement between measurements and models of net ecosystem exchange at different times and timescales using wavelet coherence: an example using data from the North American Carbon Program Site-Level Interim Synthesis. Biogeosciences. 10(11): 6893-6909.