中文摘要：

空间外差光谱具有较高的信噪比与光谱分辨率,在大气微量气体遥感领域得到重要应用,实现基线的自适应校正是光谱预处理的重要环节。基于光谱的特点,分别采用阈值拟合法和改进的经验模态法对实测近红外水汽空间外差光谱进行基线校正。结果表明,两种方法均能实现光谱基线的自动扣除;以光谱扭曲程度及光谱相似度对两种方法的校正效果进行定量评价,阈值拟合法校正后的光谱扭曲程度及光谱相似度为0.761和0.955,改进经验模态法的结果分别为0.717和0.954,说明改进经验模态法略优。在校正方法的耗时上,改进经验模态法以其特有的算法优势仅需较少的迭代次数就能获得最终的基线光谱,完成校正,耗时不足阈值拟合法的十分之一,效率更高。

英文摘要：

Spatial heterodyne spectroscopy has been used in atmospheric trace gases remote sensing field because of its high signal to noise ratio and spectral resolution, and the adaptive correction is a key link in spectrum pretreatment.Based on the spectral characteristics,two methods：the threshold fitting and improved empirical mode,were used separately to correct baseline in measured near infrared moisture spatial heterodyne spectrum.Results show：both the two methods can realize spectral baseline deduction automatically;in addition,the spectral distortion and similarity are 0.761 and 0.955,respectively,when using threshold fitting, and the spectral distortion and similarity are 0.717 and 0.954（somewhat better）,respectively,when using improved empirical mode.As far as the time-consuming is concerned,improved empirical mode using fewer iterations to attain the final baseline spectrum,which is no more than one-tenth of the threshold fitting.