嫦娥一号和二号卫星微波探测仪数据的交叉定标与一致性

嫦娥一号(CE-1)和嫦娥二号(CE-2)卫星分别于2007年和2010年发射,其上搭载着相同的微波探测仪(CELMS).由于在轨定标和探测时间不同,两星的CELMS数据存在差异.为了提高数据的一致性,基于月球极区永久阴影区(PSR),利用两步定标法对两星的CELMS数据进行交叉定标和时间校正.通过对不同纬度的亮温进行...

Cross-calibration and Consistency of Microwave Sounder Data of Chang'E-1 and Chang'E-2 Satellites

Chang'E-1 (CE-1)and Chang'E-2 (CE-2) orbiters were launched in 2007 and 2010, respectively, with the same microwave sounders CELMS (Chang'E Lunar Microwave Sounder). In-orbit calibration and time changes lead to differences between the CELMS data obtained by CE-1 and CE-2. To improve the consistency of CELMS data, the two-step calibration method is used to cross-calibrate CELMS data obtained by two orbiters based on permanently shadowed polar region of the Moon. Later, time correction was applied to reduce the effect of time on Brightness Temperature (TB). The analysis of TB at different latitudes shows that the two kinds of CELMS data have good consistency in 3GHz, 19.35GHz and 37GHz channels, while the 7.8GHz TB of CE-2 is higher than that of CE-1 in the low and middle latitudes, and the difference decreases with the increase of latitude. To avoid the effect of large longitude span, Mare Nubium impact basin was selected for further quantitative analysis of cross-calibration results. Analysis shows CELMS data are highly consistent in the region, and the average error is less than 0.2K. It is concluded that cross calibration and time correction significantly improve the consistency of the two observations and reduce the differences caused by measurement errors and time changes.