中文摘要：

草地生态系统具有植被多样性和较大的气候变异性，研究草地的能量平衡特征对认识草地的生态效应具有重要意义。利用开路涡度相关系统和常规气象观测系统的观测结果，运用最小二乘法、线性回归等方法对2010年科尔沁草甸草地生长季能量平衡特征进行分析。结果表明：科尔沁草甸草地生长季能量闭合比率为80．4％，说明该地存在不闭合现象，且闭合度居于同类观测的中上水平，涡度相关观测数据较为可靠。反射率日变化呈先降后升趋势，中午达到最低值，生长季（5-9月）在0．040-0．120之间波动，整体也呈先降后升趋势，平均值为0．061。净辐射与太阳辐射的比值为0．386，二者呈线性正相关关系。潜热通量是科尔沁草甸草地最主要的能量支出项，其次是感热通量。各分量日变化与净辐射基本相同，呈单峰型变化，日出后开始增加，中午达到最大值，之后开始减小，峰值及其出现的时间稍有不同。两种典型天气下，各分量占净辐射比例次序与生长季平均情况相同。晴天时各分量与净辐射相同，呈单峰型，而阴天时变化规律均不明显。

英文摘要：

vegetation diversity and climate variability are significant in the meadow ecosystem. Energy balance is important to study the ecological effect in the meadow ecosystem. Based on the observational data from the eddy covariance and conventionally meteorological data, the energy balance characteristics during the growth season of 2010 in Horqin meadow were analyzed by methods of a least squares and a linear regression. The results indicate that the energy balance closure rate of meadow during the growth season is 80.4%, and it means that there is an unclosed phenomenon in the study area. At the same time, the closure rate exceeds the average in similar observational sites, so it can conclude that the observational data from the eddy covariance flux measurements are reliable. The diurnal albedo decreases firstly then increases and the minimum value appears at noon;the albedo value fluctuates between 0. 040 and 0. 120 during the growth season and average is 0. 061. In general,it also decreases firstly and then increases. The ratio between net radiation （ Rn ） and solar radiation （Q） is 0. 386, and both are positively linear correlated. Latent heat flux is the main energy expenditure in Horqin meadow, and follows by sensible heat flux. Daily variations of energy balance components and net radiation are same with a single peak;their values increase after sunrise and decrease after reaching the maximum at noon;both peak values and their appearing time are different slightly. The order of ratios that each component account for net radiation under two typical weather conditions is the same with that of averages during the growing season. The variation trends of each component and net radiation are same with a single peak on sunny day, while those are not significant on cloudy day.