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    梁椿烜, 马景永, 杨睿智, 吴雅娟, 田赟, 贾昕, 查天山, 杨林. 毛乌素沙地油蒿灌丛Priestley-Taylor模型系数研究[J]. 北京林业大学学报, 2018, 40(12): 1-8. DOI: 10.13332/j.1000-1522.20180145
    引用本文: 梁椿烜, 马景永, 杨睿智, 吴雅娟, 田赟, 贾昕, 查天山, 杨林. 毛乌素沙地油蒿灌丛Priestley-Taylor模型系数研究[J]. 北京林业大学学报, 2018, 40(12): 1-8. DOI: 10.13332/j.1000-1522.20180145
    Liang Chunxuan, Ma Jingyong, Yang Ruizhi, Wu Yajuan, Tian Yun, Jia Xin, Zha Tianshan, Yang Lin. Priestley-Taylor model coefficient in a typical Artemisia ordosica shrubland in Mu Us Sandy Land of northwestern China[J]. Journal of Beijing Forestry University, 2018, 40(12): 1-8. DOI: 10.13332/j.1000-1522.20180145
    Citation: Liang Chunxuan, Ma Jingyong, Yang Ruizhi, Wu Yajuan, Tian Yun, Jia Xin, Zha Tianshan, Yang Lin. Priestley-Taylor model coefficient in a typical Artemisia ordosica shrubland in Mu Us Sandy Land of northwestern China[J]. Journal of Beijing Forestry University, 2018, 40(12): 1-8. DOI: 10.13332/j.1000-1522.20180145

    毛乌素沙地油蒿灌丛Priestley-Taylor模型系数研究

    Priestley-Taylor model coefficient in a typical Artemisia ordosica shrubland in Mu Us Sandy Land of northwestern China

    • 摘要:
      目的基于半经验半理论的Priestly-Taylor模型(PT)估算蒸散发(ET)时,主要依赖于精确确定该模型系数α在特定研究区内的适宜值,本研究就该模型系数α的适用性进行了本地化研究,以便更准确地估算干旱半干旱区的蒸散发。
      方法在中国西北干旱地区毛乌素沙地的一个生长季内,采用涡度协方差技术并结合气象数据信息,监测研究区典型油蒿灌丛地的水、热交换传输过程,以分析PT模型系数α的季节变化特征并确定其本地化估算参考值。
      结果在季节变化过程中,实际PT模型系数α整体变化较明显,展叶期内α系数呈单峰型变化趋势,完全展叶期和叶变色期内的α系数变化不明显;日均α系数最大值为0.66,最小值为0.03,全生长季α系数均值为0.23。油蒿生长季内α系数与冠层导度和饱和水汽压差呈对数正相关;土壤含水量(30 cm处)以及叶面积指数与α系数均为正相关关系。在季节变化过程中,PT模型常规系数α=1.26确定的蒸散量(ET1.26)估算值以及根据逐日温度和2 m高度处风速资料计算的PT模型系数α=0.50确定的蒸散量(ET0.50)估算值均显著大于实测蒸散发。改进的PT模型系数的本地化推荐适宜值为0.23,并且通过修正后的PT模型估算ET与实测值之间存在较好的一致性,线性斜率为0.72,R2为0.57。
      结论因此,修正的PT模型显著提高干旱半干旱区植被蒸散发估算精度,为区域植被水文过程模型提供支持。

       

      Abstract:
      ObjectiveEstimating evapotranspiration (ET) based on the semi-empirical and semi-theoretical Priestly-Taylor model (PT) mainly relies on accurately determining the appropriate value of the model coefficient α in a specific study area. This study expored the applicability of the model coefficient α. Localization studies have been conducted to more accurately estimate evapotranspiration in arid and semi-arid regions.
      MethodThis paper used the eddy covariance technique combined with micro-meteorological data to monitor the water and heat transfer processes of a typical Artemisia ordosica shrubland in growing season in Mu Us Sandy Land of northwestern China to quantify the seasonal variations in α coefficients.
      ResultThe results showed that the actual α coefficient had significant seasonal variations, peaking during the leafing period, and remaining relatively plateau during expanded leaf period and the leaf discoloration period. The maximum α coefficient was 0.66 and the minimum value was 0.03, averaging 0.23 in growing season. There was a logarithmic positive correlation between α coefficient and canopy conductance and saturated vapor pressure difference in the growing season. Soil water content (30 cm belowground) and leaf area index were positively correlated with α coefficient. Evapotranspiration estimated from the PT model with α=1.26 and with α=0.50, which was calculated from the wind speed data at 2 m height, was significantly larger than the measured evapotranspiration. The recommended localization value of the improved PT model coefficient α was 0.23, which gave better estimation of ET, linear gradient was 0.72, R2 was 0.57.
      ConclusionTherefore, the modified PT model can be used to accurately estimate evapotranspiration in arid and semi-arid regions.

       

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