雪粒径反演是冰冻圈遥感的重要研究内容之一。本研究通过设计不同雪粒径观测方案,在我国北疆地区利用SVC HR-1024野外便携式光谱仪观测了不同雪粒径的光谱特征;同时利用可拍照显微镜测量了雪粒径的大小和形状,并通过DSPP方法计算其等效粒径;最后,基于渐进式积雪辐射传输模型(ART)对反演波段和积雪形状因子进行优化,反演并验证雪粒径。研究表明DSPP方法获取积雪等效粒径是可行的,但由于同层积雪中样本选择存在较大差异,在样本选择方面需要进一步改进;近红外波段还是区分雪粒径的有效波段,在研究区积雪是干雪的条件下,基于ART优化反演波段和积雪形状因子优化方法反演雪粒径是可行的,根据试验获取在该地区雪粒径反演最佳波段为1.20μm,最佳积雪形状因子b值为3.62。
The retrieval of snow grain size is one of the important research directions for cryosphere snow remote sensing.In the present study,we designed the measurement plan of different snow grain size by different snow layer.A SVC HR-1024 ground-based spectral radiometer was used for measuring the spectral property of different snow grain size in northern Xinjiang,China.At the same time,the snow grain size and shape were measured by a hand-loupe with scale.Then the DSPP method was used to calculate the equivalent snow grain size.Finally,the asymptotic radiative transfer(ART) theory was applied to retrieve the snow grain size from measured snow spectral reflectance of different snow layer by optimizing the inversion band and the snow grain size factor "b".The retrieved snow grain size was validated by the measured snow grain size from DSPP method.The results showed that the DSPP method is an effective means of measuring the equivalent snow grain size.However,there is a large deviation of the snow grain size sample in the same snow layer.It is necessary to improve the measurement method of the single snow grain size sample;The study showed that the near-infrared bands are the most effective selection for retrieval of snow grain size.The retrieval algorithm from ART is feasible.When the snow is dry,the authors optimize the inversion band and the snow grain size factor b in the Northern Xinjiang,China.The optimal band wavelength is 1.20 μm and b is 3.62.