On the Temporal Correlation Between Photosynthesis and Soil Respiration: Reconciling Lags and Observations
Abstract
The temporal correlation between canopy photosynthesis and soil respiration (SR) is a current debate as different methods report lags for this relationship that range from hours to several days. We explore the temporal correlation between these fluxes during the growing season at four study sites, including three forests from different climates and a grassland. We used continuous (hourly average) data and applied time series analysis (wavelet coherence analysis) to identify significant temporal correlations and quantify time-lags between canopy photosynthesis and SR. Results show the existence of multi-temporal correlations at time-periods that varied between 1- and 16-days during the growing seasons at all sites. These results reconcile previous observations done by different methods. The temporal correlation was strongest at the 1-day time-period at all study sites demonstrating the strong influence of diel canopy photosynthesis on SR during the growing season. However, this temporal correlation was not uniform throughout the growing season, and was weakened when variation in soil temperature and soil CO2 diffusivity on SR were taken into account. We conclude that a comprehensive SR theory should include canopy photosynthesis, but must consider the multi-temporal influence of canopy photosynthesis, soil CO2 diffusion and soil temperature on SR.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.B11D0383V
- Keywords:
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- 0414 BIOGEOSCIENCES / Biogeochemical cycles;
- processes;
- and modeling;
- 0426 BIOGEOSCIENCES / Biosphere/atmosphere interactions;
- 0428 BIOGEOSCIENCES / Carbon cycling