The eddy covariance (EC) system is an effective tool that IRRI uses in ensuring that the mitigation and adaptation options that the institute develops to minimize the impacts of climate change on rice production have also minimal environmental footprints. It is widely employed as the standard micrometeorological method that directly measures carbon dioxide (CO2), CH4, water vapor, and heat fluxes over a large area. On the minimum, the EC can cover a 100-m radius, which corresponds to a field size of 4 hectares.
What does the EC system do?
- It monitors the impacts of land-use change in terms of greenhouse gas (GHG) emissions (i.e., CH4 and CO2) and heat fluxes.
- It provides continuous and simultaneous measurements of CH4 and CO2 emissions over a larger part of the landscape and overall ecosystem processes without disturbing the gas exchange between the soil surface and the atmosphere.
- It directly measures CH4 and CO2 fluxes at an extremely high temporal resolution (10 Hz) of 36,000 measurements per hour. The continuous EC data generation over time gives a good representation of the variability of the temporal (diurnal and seasonal) patterns of CH4 and CO2 fluxes as affected by different technologies and crop management practices.
- It takes measurements of CH4 and CO2 fluxes over the entire cropping period, in all processes (encompassing land preparation, growing, and fallow). The information generated by this technique is essential to improve the understanding not only of the global warming potential (GWP) but more so, of the net greenhouse gas budget (NGHGB) and the net ecosystem C budget (NECB) of rice-based ecosystems. More broadly, this information is relevant for process-oriented models of CH4 fluxes and the assessment of future climate change impacts due to CH4 emissions.