库布齐沙漠典型沙地人工林蒸散对比分析

人工造林使库布齐沙漠的生态快速逆转，深入理解沙地人工林的蒸散特征，对改善现有人工林的经营管理和开展人工林建设具有重要意义。利用Landsat 8、MODIS产品、气象观测资料等数据，通过基于能量平衡的SEBAL模型和MODIS MOD16蒸散产品获取库布齐沙漠典型林场2014年7月14日、7月30日、8月15日、9月7日的地表蒸散量，并采用波文比系统相关数据对估算的结果进行验证。得到以下结果：与波文比观测系统的蒸散相比，SEBAL模型反演的蒸散整体偏大，日蒸散分别多1.06、1.71、1.19、2.65 mm，两者的决定系数达0.827；MODIS MOD16产品的蒸散整体偏小，日蒸散分别少0.13、0.32、0.18、0.95 mm，两者的决定系数达0.823；在沙漠人工林斑块区域且植被类型较单一的情况下，MODIS MOD16的蒸散结果要好于SEBAL模型反演的蒸散，两者在空间分布上基本保持一致；林场蒸散较大的区域主要分布在中部和南部，而北部区域蒸散相对较小。研究结果可为其他沙地斑块人工林获取蒸散提供参考。

Comparative Analysis of Evapotranspiration of Typical Sandy Plantations in the Hobq Desert

Artificial afforestation has rapidly restored the ecology of the Hobq Desert. A thorough understanding of the characteristics of Evapotranspiration （ET） in sand plantations is of great significance for improving the management of existing plantations and developing plantation construction. By using Landsat8， MODIS products， and meteorological observations， the surface ET of a typical forest farm in the Hobq Desert on July 14， July 30， August 15 and September 7， 2014 was respectively obtained by the energy balance based SEBAL （The Surface Energy Balance Algorithm for Land） model and the MODIS MOD16 ET product. The results were verified by the Bowen ratio system. The results are as follows： Compared with the ET of the Bowen ratio observation system， the overall ET estimated by the SEBAL model was larger. The daily ET were overestimated by 1.06， 1.71， 1.19， and 2.65 mm on the above mentioned four days， with the determination coefficient of 0.827. ET from the MODIS MOD16 product was relatively smaller， and the daily ET were underestimated by 0.13， 0.32， 0.18 and 0.95 mm， respectively， with the determination coefficient of 0.823. In the case of desert plantation patches with single vegetation type， the ET obtained by the MODIS MOD16 was better than retrieved by the SEBAL model， but the spatial distribution was basically consistent. Areas with higher ET were mainly distributed in the central and south parts of the farm， while ET in the northern part was relatively smaller. The results can provide reference for other sandy plantations to obtain evapotranspiration.