基于MODIS遥感资料估算高原地表潜热通量

利用2014年夏季青藏高原9个观测站的实测资料,首先分析了夏季高原地区的湍流输送特征,并对MODIS(Moderate-Resolution Imaging Spectroradiometer)地表潜热产品在高原地区的适用性进行检验,进一步在潜热模型中引入MODIS昼夜地表温度来估算研究区的地表潜热,并将估算值与实测值进行对比。结果表明:下垫面以裸土/稀疏植被为主的阿里站能量输送以感热为主,其他观测站的湍流输送则以潜热输送为主;MODIS潜热产品在高原各地区的适用性存在差异,产品在高原东部偏东地区适用性较好,其他地区适用性较差,且高原西部的潜热有效数据大量缺失;而新提出的方法不仅可以弥补高原西部地表潜热的缺失,还可以提高地表潜热的估算精度,估算值与实测值之间相关系数达到0.77,均方根误差仅为29.8 W/m2,相对误差为35.59%;模型给出的高原地区地表潜热区域分布特征与高原的地表覆盖类型吻合较好,说明模型给出的高原地表潜热分布是合理的。

Surface Latent Heat Estimated by Remote Sensing Over the Tibetan Plateau

Based on the measured data of 9 sites over Tibetan Plateau in the summer of 2014,the characteristics of turbulent transport were analyzed first,and the further accuracy of the MOD16 latent heat flux was validated.Based on the Moderate-Resolution Imaging Spectroradiometer (MODIS) day and night land surface temperature data,the model was used to estimate the latent heat flux.Compared the estimated result with the measured data,the result showed that the main turbulent transport way was sensible heat flux in the Ali area where the underlying surface was barren or sparse,and the main turbulent transport way of other sites was latent heat flux.The applicability of the MOD16 product was difference in Tibetan Plateau regions,and the accuracy of MOD16 latent heat flux product was good in the eastern plateau,but it was not satisfied with the research in the other regions,and the valid data of western plateau was missing mostly.The model used in this paper was could not only make up for the data lack of western plateau,and could also improve the estimation precision of latent heat flux over the Tibetan Plateau.Compared to the measured data,the correlation of estimated data and observed value was significant,and the correlation coefficient was 0.77,and the root mean square was only 29.8 W/m2,and the mean absolute percent error was 35.59％.The regional distribution characteristic of latent heat flux was consisted with the surface cover types,so that the estimated result of model was reasonable over the Tibetan plateau.