3.3. Seasonal and interannual variations of GPP, ET and WUE
In spring, as the rising of solar radiation and air temperature,
GPP and ET increased (Fig. 4a). GPP peaked in May for 2006,
2009 and 2010, in July for 2007 and 2008. The monthly maximum
for GPP ranged between 173.5 and 218.5 g C m2 month1.