AMSR-E与AMSR2被动微波亮温数据交叉定标

长时间序列的对地观测数据集在研究地球环境变化及趋势分析中具有十分重要的意义。而目前的对地观测卫星寿命很少有到数十年或者几十年以上。因而,通过对具有重叠观测并且具有相近配置的传感器之间进行交叉校正获得连续的对地观测数据就显得十分必要。由于不同传感器之间系统配置以及定标过程不同等,即使同时同地的观测值也可能会有一些差异。AMSR\|E和AMSR2具有极其接近的物理配置,为了获得长时间序列的地表参数数据集,选取该传感器2013~2014年一年期18.7 GHz和36.5 GHz陆面观测数据进行对比来确定观测值之间的差异,并建立了针对两传感器在这两个频率之间基于像元观测的线性转换模型。对比发现这两个通道的观测值之间的相关性在0.98以上,两传感器同时同地亮温观测值有2~6 k的差距,这些差异在地表参数反演及长时间序列数据集的建立中应予以关注。
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Inter-calibration of AMSR-E and AMSR2 Brightness Temperature

Long time series of earth observation data records play an important role in the research of earth environment changes and trends.Few of today’s satellite sensors can continually work for more than ten years.So it becomes much necessary to conduct inter\|calibration of sensors with similar physical configuration and over-lapped observation.However,the different system parameters and process of calibration make difference even during the concurrent observation in the same zone.AMSR-E and AMSR2 share the similar configuration and it is possible for us to select the overlapped observation during the period of 2013~2014 at 18.7 GHz and 36.5 GHz.After comparing the data,a least-square linear model was established to calibrate the two sensors.The results show that correlation between them up to 0.98 and the value difference ranges from 3 K to 6 K.This difference should not be ignored when constructing a long-term data record or during the retrieval of the land surface parameters.