热层大气密度对太阳辐射27 d短期震荡的响应规律  

Thermospheric Mass Densities'Response to the Solar Radiation's Short-term Variation with 27-d Period

作　　者：汪宏波[1,2] 张明江[1,2] 熊建宁 WANG Hong-bo;ZHANG Ming-jiang;XIONG Jian-ning(Purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210023,China;Key Laboratory of Space Object and Debris Observation,Chinese Academy of Sciences,Nanjing 210023,China)

机构地区：[1]中国科学院紫金山天文台,南京210023 [2]中国科学院空间目标与碎片观测重点实验室,南京210023

出　　处：《天文学进展》2023年第3期401-414,共14页Progress In Astronomy

基　　金：国家自然科学基金天文联合基金(U1931136)。

摘　　要：在近地空间目标和碎片的定轨预报任务中,需要准确计算热层中性大气密度。太阳辐射约27 d周期的短期震荡是影响大气密度的一种重要的空间环境因素,它会引起大气密度在全球尺度上的涨落。选择CHAMP、GRACE-A和SWARM-C这3颗极轨卫星星载加速仪数据推导出的大气密度资料,提取其中的27 d短期变化信号,与太阳极紫外辐射(S_(10)指数)的27 d短期变化进行多元回归分析,研究热层大气密度对太阳辐射短期变化的响应规律,及其在不同高度、辐射水平、昼夜半球和纬度等方面的差异。结果表明:太阳辐射短期变化对大气密度的影响与高度负相关(主要因素)、与辐射水平正相关(次要因素);对白天半球的影响是夜间半球的约2倍;在白天半球,辐射影响随着纬度增大而减弱,夜间半球恰好相反。将以上观测结果与NRLMSISE00模型模拟结果对比,发现模型低估了太阳辐射短期变化对大气密度影响的(50%~60%),且低估了高度差异,但高估了辐射水平差异。利用SOHO卫星对太阳26~34 nm波长极紫外辐射1 h分辨率的测量值,研究了大气密度对辐射的响应延迟时间,约为18 h(0.75 d)。研究结果对于优化大气模型建模、修正大气密度具有借鉴价值。In the mission of orbit determination and prediction for space object and debris in low earth orbit,accurate mass densities and its short-term variation of thermospheric neutral gas are required.Solar radiation’s short-term variation with 27-d period is an important space environment factor because it drives the global-scale fluctuation of thermospheric mass densities synchronously.This paper uses the neutral mass densities data derived from the non-gravitational acceleration measurements by three polar-orbit satellites,such as CHAMP,GRACE-A and SWARM-C.The short-term variation of these densities was extracted and compared with the solar extreme ultraviolet(EUV)radiation,indicated as S_(10) index,to study the thermosphere response to radiation.Their differences at various height,radiation level,dayside/nightside hemisphere,and latitude were discussed.The multivariate regression analysis method was used to calculate the correlation coefficient and slope between the density and solar radiation.The results were as follows.(1)solar variation’effect on the density is negative correlation with altitude(major factor)and positive with solar activity level(minor factor).(2)the effect in dayside hemisphere is about 1 time stronger than that in the nightside.(3)the effect decreased as the rising of latitude in the dayside,while in the nightside the opposite is the case.It is implied that the direction of energy and temperature conduction in the dayside is from low equator region to high latitude,and in the nightside from high to low latitude.By comparing these observation results with the simulation used NRLMSISE00 model,it is indicated model underestimate the effect of solar radiation’s short-term variation on densities for about 50%60%,and its difference at various altitude,while overestimate the difference caused by average level of solar radiation.The response lag time of densities to solar radiation was studied by using EUV measurement with 1-h temporal resolution from SOHO project,indicating the lag time was ab

关 键 词：空间天气 热层大气密度 太阳极紫外辐射 27 d短期变化 

分 类 号：P41[天文地球—大气科学及气象学]