NRLMSISE-00大气模型与GRACE和CHAMP卫星大气密度数据的对比分析

利用GRACE(Gravity Recovery And Climate Experiment)和CHAMP(Challenging Mini-Satellite Payload)卫星2002-2008年的大气密度数据与NRLMSISE-00大气模型密度结果进行比较,分析了模型密度误差及其特点.结果显示,NRLMSISE-00大气模型计算的密度值普遍偏大,其相对误差随经纬度变化,在高纬度相对较小;相对误差随地方时变化,在02:00LT和15:00LT左右较大,10:00LT和20:00LT左右较小.通过模型密度相对误差与太阳F_10.7指数的对比分析发现,在太阳活动低年模型相对误差最大,而在太阳活动高年相对误差较小;将模型结果分别与GRACEA/B双星和CHAMP卫星的密度数据进行比较,发现对于轨道高度更高的GRACE卫星轨道,模型相对误差更大;在地磁平静期,相对误差与地磁ap指数(当前3h)相关性不强,但是在大磁暴发生时,误差急剧增大. 

Comparison of the Thermospheric Densities Between GRACE/CHAMP Satellites Data and NRLMSISE-00 Model

NRLMSISE-00 model is widely used in orbit determination and prediction of low-Earth orbit satellites. In order to calibrate the atmospheric density of NRLMSISE-00, the density errors of the model were analyzed by comparing with the observations from GRACE and CHAMP satellites. The density of the model was generally larger than that observed by GRACE and CHAMP satellites, especially under low solar activity. The density of the model showed higher accuracy at high latitude and its error varied with latitude and longitude. At the same location on the same orbit, density error of the model varied with local time and reached its maximum at 02:00LT and 15:00LT while reached its minimum at about 10:00LT and 20:00LT relatively. The 10.7cm solar radio flux (F_10.7 index) showed high correlation with the density errors. The density of the model showed low accuracy during the solar minimum while good accuracy during the solar maximum. The model density showed better result at CHAMP satellite orbit with lower altitude comparing to the GRACE orbit. The error has less correlation with ap index during relatively quiet period of geomagnetic field (ap< 27).