Some thoughts about long-term eddy fluxes: A long term eddy correlation measurement is not a "thermometer". Not all covariances are surface fluxes. Long term measurements offer a strong statistical basis for inference of response of the ecosystem to climate forcing and other environmental influences, and for carbon fluxes and budgets.

Application of long-term eddy fluxes to carbon budgets requires vigorous assessment of systematic errors. Statistical inference and physical reasoning have to be brought together to do this. Site particulars are very important. Sites differ. Reduce effects of poorly controlled observations, weak parameterizations or inappropriate analytical methods which may obscure systematic errors by statistical inference. Focus on the important issues and on what you can learn from similar sites.

Science steering group? E.g. A. Nobre (chair), Fitzjarrald, Malhi, Kruijt, Martinelli, de Rocha; at most 1 or 2 other "senior" people: Establish a common core of tests and analyses to be presented to the group, facilitate strong collaboration, help newer groups, and develop assessments and (where appropriate) consensus. Strong role for CPTEC. calibration. "filtering". day-night bias (even a small one!). redundancy. inter-comparison. "golden files". coordinated exchange of data, raw and processed. Communication by , another workshop in an appropriate spot in a year or so.