Poster, Review of TERRECO Phase II, Bayreuth, Germany: 2013-01-17
Abstract:
The landscape of the Haean Catchment is characterized with mosaic-fetches of agricultural fields at different scales, and agricultural management (e.g., agricultural composition and structure) modulates landscape carbon dynamics in the catchment. Studies on cross-scale connection of landscape carbon dynamics in agricultural fields, where human activity is a main agent of ecosystem changes, are rare. The objectives of the study are to develop a biological fingerprint of carbon dynamics using multi-scale observations (i.e., chamber, eddy covariance, model, and remote sensing) and to connect individual observation of carbon dynamics at different scales through cross-scale interactions. As the first step in our approach, we examined ecosystem respiration (R eco ), which is one of the major components of the carbon cycle, using chamber and eddy covariance (EC) measurements at rice paddy and potato sites, which are dominant crops in the catchment. Based on the “Lloyd and Taylor equation” (see Eq. 1 in the corresponding poster), R eco was estimated by using the observed R eco over different temporal intervals (i.e., daily versus seasonal for the chamber method; monthly versus seasonal for the EC method; nighttime versus daytime for the EC method). Then, the estimated R eco was compared against each method. The observed R eco by the chamber and EC methods were similar at the rice paddy site during the irrigated period, whereas the former was two times higher than the latter during the non-irrigated period. At the potato site, R eco by the chamber method was larger than that obtained by the EC method during the entire measurement period. Influence of temporal interval on estimating ability on R eco was prominent when the chamber data were used, showing a better prediction of R eco over a shorter interval for both crops. However, the influence was obscure with respect to the estimated R eco from the EC data. Estimates of R eco, by the chamber data over the seasonal time interval was on average about 10% higher than that by the EC method at the rice paddy, whereas the former was about 180% higher than the latter. In the corresponding poster, we discuss the discrepancy in the magnitudes of Reco between the chamber and the EC methods and the influence of temporal interval on Reco model parameterization.