Seasonal Changes of Energy Fluxes in an Estuarine Wetland of Shanghai, China

The energy budget and regulating factors were investigated over an estuarine wetland during one year of continuous measurement in 2006. The results show that the seasonal changes of the energy fluxes and Bowen ratio (β) were greatly affected by incoming shortwave radiation and canopy growth. During the non-growing season and early-growing season, sensible heat (H) dominated the energy flux, and β could reach a maximum of 2.5, while during most of the growing season, latent heat dominated the energy flux and β fluctuated from 0.4 to 1.0. The energy budget ratio in growing season was about 0.76, and the value would be higher if heat exchange during tidal flooding was included. During tidal flooding days, β was slightly higher than that at exposure days in most cases. Vegetation cover seems exert little effect on energy partitioning except in March when the standing dead grass intercepted the incoming radiation that might reach the soil surface and reduce the turbulence between soil and atmosphere, thus suppressing the evaporation from the soil though the soil mositure was high at that time.