Closing the carbon budget of estuarine wetlands with tower‐based measurements and MODIS time series

Abstract

Since the publication of Yan et al. (2008) earlier this month, Dr. Asko Noormets of North Carolina State University has communicated with us about potential errors involved in this publication. Consequently, we found that the units used for several variables were wrong. This corrigendum provides the following corrections: The label of the horizontal axis in Figure 2 (Page 1693) should read PAR (μmol m−2 s−1). GPP, NEE and PAR in 3-5 as well as Table 3 were incorrectly presented because of unit conversion. For GPP and NEE, the original data needs to be timed by (1800(s) × 12(g mol−1)/1 00 0000) and for PAR, it needs to be timed by (1800(s)/10 00 000). Here, we provide the correct versions of these figures and the table. Seasonal changes in net ecosystem exchange (NEE) of CO2 and gross primary production (GPP) (a–c); photosynthetically active radiation (PAR) and mean air temperature (T) (d–f); vegetation indices (NDVI, normalized difference vegetation index; EVI, enhanced vegetation index and LSWI, land surface water index) (g–i) in the 2005 growing season at Dongtan wetlands, Shanghai, China. Comparisons between vegetation indices (EVI, NDVI) and gross primary production (GPP) among three sites at Dongtan, China (a, Site D; b, Site M; c, Site S). Simple linear regression models between GPP and vegetation (NDVI, EVI) are shown with data combined from all three sites (d). The solid line represents the relationship between GPP and EVI (GPP=19.31 × EVI+1.25, R2=0.520) and the dashed line between GPP and NDVI (GPP=11.90 × NDVI+0.84, R2=0.460). Comparisons of seasonal changes in gross primary production from eddy covariance towers (GPPEC), the MODIS-based model (GPPMODIS) and the hybrid model (GPP′) Eqn (10) for the 2005 growing season at three sites (a, Site D; b, Site M; c, Site S). Simple linear relationships between GPPEC, GPPMODIS and GPP′ are presented with data combined from all three sites (GPPEC=3.29 × GPPMODIS+1.47, R2=0.550; GPPEC=1.03 × GPP′−0.10, R2=0.876) (d). Because of the above errors, some results in the paper need to be changed accordingly. These include: Abstract (Page 1690): … The average GPP calculated from eddy covariance between March and November was 5.65 g C m−2 day−1, whereas that from the LUE model was 1.27 g C m−2 day−1: … The average GPP from the modified model increased to 5.69 g C m−2 day−1, … Results (Page 1696): … The Spartina-dominated wetland near the dike (Site D) had the highest peak NEE (−12.16 g C m−2 day−1) and GPP (14.46 g C m−2 day−1) and exhibited the most obvious seasonal pattern. Average values of NEE (GPP) were −4.36 (6.38), −3.97 (5.98) and −3.68 (4.61) g C m−2 day−1 for sites D, M and S, respectively, … … The standard error of the estimate was 1.27 when all three variables (TH, LSWI and ET) were considered … The citation of Eqn (9) in the title of Table 2 should read Eqn (6). We incorrectly referred Davidson et al. (2006) (Page 1695), as the authors did not publish the corresponding equation. Therefore, this citation should be removed. The latent heat of vaporization (Page 1694) should read 44 kJ mol−1. These corrections, however, do not affect the overall conclusions of the paper. The authors apologize for any confusion caused.