ZH-1卫星LAP数据校正及与Swarm B数据差异分析

针对ZH-1卫星朗缪尔探针(LAP)原位电子密度观测数据远小于其他系统观测数据的问题，本文利用COSMIC及COSMIC 2在中纬度地区的掩星数据，得到对LAP数据的校正关系，并进一步利用与ZH-1具有相似飞行高度的Swarm B卫星全球等离子观测数据对校正后的LAP数据进行检验，以评估校正结果的准确性和可靠性.检验结果认为：(1)校正后的LAP数据与Swarm B数据基本一致，两者在中纬度地区符合较好，在赤道地区仍有明显偏差.(2)这一偏差与观测数据值的大小有关，在较小观测值时两者符合较好，较大观测值时差异变大，可能与两个卫星载荷的不同动态响应特性有关.(3)经过线性校正的LAP数据不会改变相对变化关系，但拓展了数据的应用场合.

Calibration of the LAP measurements obtained by ZH-1 satellite and analysis of the bias with that from Swarm B satellite

A problem is found from the LAP observations on board ZH-1 satellite that the in situ electron density measurements from this payload are much smaller than that from other simultaneous systems. To solve this problem, a calibration relationship is obtained using the collocated RO (Radio Occultation) data observed at mid-latitudes from the COSMIC and COSMIC 2 missions. The calibrated LAP measurements based on this relationship are validated using the collocated LP measurements from the Swarm B satellite orbiting at a similar altitude as that of the ZH-1 satellite to evaluate the accuracy and reliability of the calibrated data. The results show that: (1) The calibrated LAP measurements are generally in accord with the Swarm B measurements, and the two are in good agreement in mid-latitude regions, but a significant deviation is found in the equator and its adjacent regions. (2) This deviation is obviously related to data values; the two agree well when data values are relatively small, and the differences become larger when data values are relatively large, which may result from the different dynamic response characteristics of the payloads from the two missions. (3) The linear calibration does not change the relative variations in the LAP measurements, but it will expand the application domain of the data.