三江平原季节性积水沼泽湿地能量平衡要素研究

Components of Energy Balance in Seasonal Waterlogged Marsh in the Sanjiang Plain

2005年6月1日到8月30日,在中国科学院三江平原沼泽湿地生态试验站沼泽综合试验场季节性积水沼泽湿地,观测了净辐射和土壤热通量;利用Penman-Monteith公式和地表能量平衡方程式计算了潜热通量和感热通量;同时用SHAW模型对以上4个能量平衡要素进行了模拟研究,并用观测值以及模型效率、标准差和平均方差检验和评价了其模拟效果。结果表明,三江平原季节性积水沼泽湿地净辐射在6月末至7月初较大;潜热通量主要受净辐射的影响,与土壤水分关系不密切;沼泽湿地地表在6月初至8月中旬以吸收能量为主,8月末以后则开始释放能量;感热通量在植物生长季的初期和末期较大,在中期则比较小。SHAW模型能较好的模拟出沼泽湿地的净辐射、潜热通量和土壤热通量;该模型虽对感热通量的模拟结果并不理想,但能较好的模拟其变化趋势。这说明SHAW模型基本适用于对季节性浅积水沼泽湿地(水深小于10cm)能量平衡各要素的模拟。

To study the wetland energy balance is an important way to understand the process of water and heat transfers and it can reflect the character of water and heat in wetland. The SHAW （ the Simultaneous Heat and Water） model was applied to simulate the variations of components of the energy balance in seasonal waterlogged marsh in the Sanjiang Plain, where water depth is less than 10 cm. The SHAW model describes a physical system consists of a vertical , one - dimensional profile extending from the vegetation canopy, snow, residue or soil surface to a specified depth within the soil. The system is represented by integrating detailed physics of a plant canopy, snow, residue and soil into one simultaneous solution. From June 1 to August 30, 2005, net radiation, ground heat flux measured and latent heat flux which was calculated with Penman -Monteith equation and sensible heat flux which was calculated with the energy balance equation in the seasonal waterlogged marsh （water depth is less than 10 cm） located in the comprehensive test experimental station in the Sanjiang Plain, Chinese Academy of Sciences. At the same time, SHAW model was used to simulate the components of the energy balance and used model efficiency, root mean square error and mean bias error to evaluate the simulation effect. The results showed that net radiation gradually increased from the early of June and reached the maximum in the end of June and early of July, then gradually decreased ; latent heat flux was mainly effected by net radiation, and not close to soil moisture; ground heat flux gradually increased from the early of June and reached the maximum in June 22, then decreased; sensible heat flux was smallest in mid - growing season and was larger in early and end of growing season due to latent heat flux was larger in mid - growing season and smaller in the early and end of growing season in seasonal waterlogged marsh of the Sanjiang Plain. SHAW model can better simulate net radiation, latent heat flux and ground heat flux in the marsh. Although the simulation of sensible heat flux was not well, the trend of simulated sensible heat was accorded with that of the calculated.