Dry Season Energy Balance of a Coniferous and Broad-leaved Mixed Forest at Dinghushan Mountain, Southern China
鼎湖山针阔混交林旱季能量平衡研究

Net radiation and heat fluxes in a coniferous and broad-leaved mixed forest were monitored by a microclimate monitor system, an eddy covariance (EC) open-path system, and soil heat flux plates during January 9-23, 2003 in Dinghushan Mountain, Southern China. The average net radiation (Rn) above the canopy was 53.14 W m-2. The average latent heat flux (LE) and sensible heat flux (Hs) above the canopy were 57.18 W m-2 and 43.40 W m-2, while the LE and Hs below the forest canopy were 12.61 W m-2 and 7.61 W m-2, respectively. The LE and Hs fluxes estimated by the EC and by the Bowen ratio energy balance method were very similar in daytime, but very different in the rest of the day. The diurnal changes of soil heat flux (Gt) were in an "S" shape. The average Gt was -1.50 W m-2,which suggested that soil was one of the heat sources. The total Gt was only 84.0% of the soil heat flux at 5 cm depth, which indicated that the heat stored by the soil should not be ignored in spite of the thin soil layers. A significant correlation (r = 0.8517) between the amount of heat flux (LE+Hs) and available energy (Rn-Gt) with a slope of 0.9128 suggested that the LE and Hs measured by EC at the research site were within the reasonable range reported in the literature.