World Library  


Add to Book Shelf
Flag as Inappropriate
Email this Book

Evaluating the Agreement Between Measurements and Models of Net Ecosystem Exchange at Different Times and Time Scales Using Wavelet Coherence: an Example Using Data from the North American Carbon Program Site-level Interim Synthesis : Volume 10, Issue 2 (19/02/2013)

By Stoy, P. C.

Click here to view

Book Id: WPLBN0004004378
Format Type: PDF Article :
File Size: Pages 39
Reproduction Date: 2015

Title: Evaluating the Agreement Between Measurements and Models of Net Ecosystem Exchange at Different Times and Time Scales Using Wavelet Coherence: an Example Using Data from the North American Carbon Program Site-level Interim Synthesis : Volume 10, Issue 2 (19/02/2013)  
Author: Stoy, P. C.
Volume: Vol. 10, Issue 2
Language: English
Subject: Science, Biogeosciences, Discussions
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2013
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Citation

APA MLA Chicago

Hollinger, D. Y., Dietze, M., Richardson, A. D., Riley, W. J., Vargas, R., Kucharik, C. J.,...Tian, H. (2013). Evaluating the Agreement Between Measurements and Models of Net Ecosystem Exchange at Different Times and Time Scales Using Wavelet Coherence: an Example Using Data from the North American Carbon Program Site-level Interim Synthesis : Volume 10, Issue 2 (19/02/2013). Retrieved from http://www.ebooklibrary.org/


Description
Description: Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA. 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 misfit, leaving unclear the steps required to improve model response to environmental drivers that vary on characteristic frequencies. Wavelet coherence can quantify the times and frequencies at which models and measurements are significantly different. We applied wavelet coherence to interpret the predictions of twenty ecosystem models from the North American Carbon Program (NACP) Site-Level Interim Synthesis when confronted with eddy covariance-measured net ecosystem exchange (NEE) from ten ecosystems with multiple years of available data. Models were grouped into classes with similar approaches for incorporating phenology, the calculation of NEE, and the inclusion of foliar nitrogen (N). Models with prescribed, rather than prognostic, phenology often fit NEE observations better on annual to interannual time scales in grassland, wetland and agricultural ecosystems. Models that calculate NEE as net primary productivity (NPP) minus heterotrophic respiration (HR) rather than gross ecosystem productivity (GPP) minus ecosystem respiration (ER) fit better on annual time scales in grassland and wetland ecosystems, but models that calculate NEE as GPP – ER were superior on monthly to seasonal time scales in two coniferous forests. Models that incorporated foliar nitrogen (N) data were successful at capturing NEE variability on interannual (multiple year) time scales at Howland Forest, Maine. Combined with previous findings, our results suggest that the mechanisms driving daily and annual NEE variability tend to be correctly simulated, but the magnitude of these fluxes is often erroneous, suggesting that model parameterization must be improved. Few NACP models correctly predicted fluxes on seasonal and interannual time scales where spectral energy in NEE observations tends to be low, but where phenological events, multi-year oscillations in climatological drivers, and ecosystem succession are known to be important for determining ecosystem function. Mechanistic improvements to models must be made to replicate observed NEE variability on seasonal and interannual time scales.

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

Excerpt
Zhan, X. W., Xue, Y. K., and Collatz, G. J.: An analytical approach for estimating CO2 and heat fluxes over the Amazonian region, Ecol. Model., 162, 97–117, 2003.; Zhou, X. L., Peng, C. H., Dang, Q. L., Sun, J. F., Wu, H. B., and Hua, D.: Simulating carbon exchange in Canadian boreal forests I: model structure, validation, and sensitivity analysis, Ecol. Model., 219, 287–299, 2008.; Akaike, H.: A new look at the statistical model identification, IEEE T. Automat. Contr., 19, 716–723, 1974.; Arain, M. A., Yaun, F., and Black, T. A.: Soil-plant nitrogen cycling modulated carbon exchanges in a western temperate conifer forest in Canada, Agr. Forest Meteorol., 140, 171–192, 2006.; Baker, I. T., Prihodko, L., Denning, A. S., Goulden, M., Miller, S., and da Rocha, H. R.: Seasonal drought stress in the Amazon: reconciling models and observations, J. Geophys. Res., 113, G00B01, doi:10.1029/2007JG000644, 2008.; Barr, A. G., Black, T. A., Hogg, E. H., Kljun, N., Morgenstern, K., and Nesic, Z.: Inter-annual variability in the leaf area index of a boreal aspen-hazelnut forest in relation to net ecosystem production, Agr. Forest Meteorol., 126, 237–255, 2004.; Causarano, H. J., Shaw, J. M., Franzluebbers, A. J., Reeves, D. W., Raper, R. L., Balkcom, K. S., Norfleet, M. L., and Izaurralde, R. C.: Simulating field-scale soil organic carbon dynamics using EPIC, Soil Sci. Soc. Am. J., 71, 1174–1185, 2007.; Detto, M., Molini, A., Katul, GG., Stoy, P. C., Palmroth, S., and Baldocchi, D. D.: Assessing cause and effect in ecological time series: an application of conditional Granger's spectral causality theory, Am. Nat., 179, 524–535, 2012.; Dietze, M., Vargas, R., Richardson, A. D., Stoy, P. C., Barr, A. G., Anderson, R. S., Arain, A., Baker, I. T., Black, T. A., Chen, J. M., Ciais, P., Flanagan, L. B., Gough, C. M., Grant, R. F., Hollinger, D. Y., Izaurralde, C., Kucharik, C. J., Lafleur, P. M., 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., Tian, H., Verbeeck, H., and Verma, S. B.: Characterizing the performance of ecosystem models across time scales: a spectral analysis of the North American Carbon Program site-level synthesis, J. Geophys. Res., 116, G04029, doi:10.1029/2011JG001661, 2011.; Fisher, J. I., Richardson, A. D., and Mustard, J. F.: Phenology model from surface meteorology does not capture satellite-based greenup estimations, Glob. Change Biol., 13, 707–721, doi:10.1111/j.1365-2486.2006.01311.x, 2007.; Flanagan, L. B., Wever, L.&


 

Click To View

Additional Books


  • Anticorrelated Observed and Modeled Tren... (by )
  • Kinetic Bottlenecks to Chemical Exchange... (by )
  • A Halocarbon Survey from a Seagrass Domi... (by )
  • Carbon Budget of Tropical Forests in Sou... (by )
  • Biodiversity for Multifunctional Grassla... (by )
  • Role of Net Radiation on Energy Balance ... (by )
  • Autonomous Profiling Float Observations ... (by )
  • Temperature Thresholds for Arctic Plankt... (by )
  • Annual Co2 Budget and Seasonal Co2 Excha... (by )
  • Authigenic Phases and Biomass Contents D... (by )
  • Differential Gene Expression in the Muss... (by )
  • Sea-to-air and Diapycnal Nitrous Oxide F... (by )
Scroll Left
Scroll Right

 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.