电离层残差对掩星反演温度精度的影响

The effects of residual ionospheric errors on GPS radio occultation temperature

本文以MSIS90大气模式和3D NeUoG电离层模式为大气背景,用三维射线追踪法模拟研究了太阳活动强度、地方时、掩星平面方位角对弯曲角电离层残差和温度电离层残差的影响,以及电离层残差对全球日平均温度的影响.结果表明：电离层残差是平流层顶部（35-50 km）和中间层底部（50-70 km）掩星大气温度反演的主要误差.在太阳活动活跃期,电离层残差对单一掩星事件的平流层顶部平均温度的影响可达1.8 K,中间层底部平均温度的影响可达7 K;对全球日平均温度的影响在平流层顶可达-0.6 K,在70 km高度处可达1.2 K.发展新的电离层改正方法或电离层残差修正算法对提高掩星大气反演精度和全球气候监测意义重大.

In order to investigate the effects of residual ionospheric errors （RIEs） on radio occultation （RO） temperature profiles due to solar activity, local time and azimuth of occultation plane, two simulation schemes have been conducted using the models of MSIS90 for atmosphere and 3D NeUoG for ionosphere, and a 3D ray tracing approach. The results show that during solaractive periods mean temperature errors mainly resulted from RIEs. In the upper stratosphere （35-50 kin） and lower mesosphere （50-70 kin） the statistical errors could reach about 1.8 K and 7 K, respectively, and global mean temperature errors could reach about --0. 6 K at the stratopause and about 1.2 K at 70 km altitude. These results suggest that the RIE is a major temperature error at the altitude of 35 - 70 km. Hence, developing more effective ionospheric correction approaches is significant for improving the accuracy of RO retrievals and global climate monitoring.