Huo Wen

Estimation of the land surface emissivity in the hinterland of Taklimakan Desert

An accurate accounting of land surface emissivity (ɛ) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets. Since ɛ is one of the important parameterizations in land surface models (LSMs), accurate accounting also improves the accuracy of surface temperatures and sensible heat fluxes simulated by LSMs. In order to obtain an accurate emissivity, this paper focuses on estimating ɛ from data collected in the hinterland of Taklimakan Desert by two different methods. In the first method, ɛ was derived from the surface broadband emissivity in the 8-14 μm thermal infrared atmospheric window, which was determined from spectral radiances observed by field measurements using a portable Fourier transform infrared spectrometer, the mean ɛ being 0.9051. The second method compared the observed and calculated heat fluxes under nearneutral atmospheric stability and estimated ɛ indirectly by minimizing the root-mean-square difference between them. The result of the second method found a mean value of 0.9042, which is consistent with the result by the first method. Although the two methods recover ɛ from different field experiments and data, the difference of mean values is 0.0009. The first method is superior to the indirect method, and is also more convenient.