关键词: 大豆田, 潜热通量, 感热通量, 水分平衡, 能量分配

Abstract: 【Objective】 The quantification of variation regularity of surface turbulent heat flux was studied in order to provide a basis for clarifying the energy balance in soybean field. 【Method】 Based on eddy covariance data in soybean field in the Sanjiang Plain, the diurnal and seasonal variation of turbulent heat flux, water balance and energy partitioning were analyzed. 【Result】Diurnal variation curves of latent and sensible heat flux were both obviously single peaked in soybean fields. Seasonal variation of latent heat flux was also clear. Latent heat flux generally reached the maximum during the end of June and early July, which was strongly linearly positive dependent on net radiation. However, when the precipitation became small, latent heat flux was also affected by it. The sensible heat flux showed a declining trend, which was also strongly linearly positive dependent on net radiation, but both sensible heat flux and Hs/Rn are strongly negative dependent on precipitation. Total precipitation was obviously greater than total evapotranspiration during the growing season of soybean, while uneven distribution of precipitation made the water budget become deficit in short term. The characteristics of seasonal variation of Bowen ratio was not exactly same from 2005 to 2007, and Bowen ratio had a strong negative relationship with monthly precipitation and leaf area index. 【Conclusion】 Latent and sensible heat flux in soybean field showed a clear single peak at the diurnal scale. Surface water is surplus and latent heat flux, sensible heat flux and energy partition in soybean field is determined by net radiation, precipitation and plant development.

Key words: soybean field, latent heat flux, sensible heat flux, water balance, energy partition