This paper summarises our work from five different at which we have compared CenW simulations with eddy-covariance based measurements. Three sites are in New Zealand (Scott Farm, Beacon Farm and Troughton Farm) and two in Lusignan in France of which one was regularly grazed while the other was mowed.  
Model-data comparison was very good for all sites, with particularly good agreement for evapotranspiration fluxes (model efficiencies of weekly averaged comparisons, EF, ranging from 0.85-0.96. Photosynthesis (EF: 0.79-0.90) and respiration rates (EF: 0.67-0.90) and net ecosystem production (EF:0.54-0.78). Analysis of these data showed that it could be difficult to completely capture grazer respiration, especially when it relied on gap-filling to generate complete data sequences. This affected measurements at Scott Farm and the grazed site at Lusignan. Consequently, Scott Farm and the grazed site at Lusignan were the sites with lowest model efficiencies for respiration rates and net ecosystem production. 
The multi-site data compilation then allowed us to extract relevant information about the functioning of pasture systems. First, we studied biophysical limits to pasture photosynthetic carbon gain and reported appreciable ongoing photosynthesis down to temperatures as low as 0°C (at Lusignan). This carbon gain, however, was matched by corresponding respiratory carbon losses so that net ecosystem productivity over the winter months remained close to zero. Positive ecosystem productivity and consequent plant growth only recommenced with the warmer temperature of the following spring.
Second, detailed analysis of the gas exchange pattern at Beacon Farm revealed a substantial reduction in net ecosystem production after grazing that was linked to a reduction in photosynthesis rather than any increase in respiration rate. Photosynthesis is reduced after grazing partly just because of the reduction in leaf area and consequently reduced light interception. However, the leaf-area reduction could account for only 1/3 of the observed reduction in photosynthesis, with reasons for the additional 2/3 of the observed reductions not yet known. This is a quantitatively important reduction in potential productivity that can lead to an annual loss of 3-4 tC ha-1 yr-1 in potential carbon gain. Gaining a better understanding of the processes responsible for this loss holds the prospect of possibly being able to modify grazing procedures to minimise these losses in future.
