中文摘要：

【目的】明确大豆田地表湍流热通量变化特征及其规律,为阐明大豆田地表能量平衡奠定基础。【方法】以三江平原大豆田为研究对象,基于涡度相关数据分析大豆生长季地表湍流热通量的日变化、季节变化、地表水分平衡和地表能量分配特征及其主控因子。【结果】大豆田地表潜热和感热通量日变化均表现为明显的单峰特征。潜热通量季节变化特征明显,一般于6月下旬至7月上旬达到最大值,其与净辐射呈显著线性正相关关系,但当降水量较少时也与降水量呈显著线性正相关关系。大豆田地表感热通量整体呈下降趋势,亦与净辐射呈显著线性正相关关系,但感热通量Hs和Hs/Rn均与降水量呈显著负相关关系。大豆生长季内降水总量明显大于蒸散总量,但降水分布不均也会使得短期内出现水分收支亏缺。2005—2007年,大豆田波文比季节变化特征不完全相同,波文比与降水量和叶面积指数均呈显著负相关关系。【结论】三江平原大豆田潜热和感热通量单峰日变化特征显著,生长季内大豆地表水分盈余。净辐射、降水量和植被发育是影响大豆田潜热和感热通量以及能量分配的主要因子。

英文摘要：

【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.