CAJ | 학술논문

对2003年(太阳活动较高年)至2007年(太阳活动低年)CHAMP卫星的热层大气密度观测数据进行了经验正交函数(EOF)分析,得到了400 km高度上白天平均大气密度ρ的太阳活动周变化与年度变化等不同变化分量.研究结果表明,ρ受太阳活动影响较大,其太阳周变化分量与F10.7指数变化之间的相关系数可高达94.5%;ρ的太阳周变化分量随纬度增加而减小,且在中高纬地区,南半球的值明显大于北半球的值,在低纬地区则出现基本对称的双峰分布,即赤道质量密度异常(EMA)结构.在ρ的年变化中,呈现出明显的季节变化,即夏季低冬季高;同时ρ的年变化幅度随太阳活动增加而增强,随纬度增加而增强.将本文结果与经验模式NRLMSISEOO在观测条件下的输出数据进行对比,发现两者的太阳周变化与年变化分量基本一致,但本文观测数据的太阳周成分随纬度变化略小,年变化幅度略大,且NRLMSISEOO模式不能再现EMA结构.研究结果对揭示热层气候学变化特征具有重要意义.
대2003년(태양활동교고년)지2007년(태양활동저년)CHAMP위성적열층대기밀도관측수거진행료경험정교함수(EOF)분석,득도료400 km고도상백천평균대기밀도ρ적태양활동주변화여년도변화등불동변화분량.연구결과표명,ρ수태양활동영향교대,기태양주변화분량여F10.7지수변화지간적상관계수가고체94.5%;ρ적태양주변화분량수위도증가이감소,차재중고위지구,남반구적치명현대우북반구적치,재저위지구칙출현기본대칭적쌍봉분포,즉적도질량밀도이상(EMA)결구.재ρ적년변화중,정현출명현적계절변화,즉하계저동계고;동시ρ적년변화폭도수태양활동증가이증강,수위도증가이증강.장본문결과여경험모식NRLMSISEOO재관측조건하적수출수거진행대비,발현량자적태양주변화여년변화분량기본일치,단본문관측수거적태양주성분수위도변화략소,년변화폭도략대,차NRLMSISEOO모식불능재현EMA결구.연구결과대게시열층기후학변화특정구유중요의의.
The Empirical Orthogonal Function (EOF) analysis was applied to study the thermo-spheric total mass density at the altitude of 400 km with the data obtained from German CHAMP satellite during the interval from 2003 to 2007, when the solar activity is in declining period. The solax cycle and yearly variations of the thermospheric total mass density p are obtained. It is found that the total mass density p was obviously affected by the solar activity, the correlation coefficient between solar cycle variation component of p and F10.7 index can reach 94.5%. At the mid-and high-latitudes, the amplitude of solar cycle variation is larger in the south hemisphere than in the north. The amplitude of the solar cycle variation is decreased as the latitudes change from low to high. At low latitudes there exists a structure of double crests which is recently known as the Equatorial Mass density Anomaly (EMA). In the yearly variation of the total mass density, there is a seasonal variation that the density is larger in summer than in winter. The amplitude of the yearly variation of density p increases with solar .F10.7 index as well as the absolute latitude. Comparing the result of CHAMP data with the output of NRLMSISEOO model under the input of the same condition of observation, it is found that both the solar cycle and the yearly variations of thermo-spheric total mass density are in good agreement. Even though, the latitude difference of the solar cycle variation of p is a little bigger from NRLMSISEOO than CHAMP data and there is no EMA structure in NRLMSISEOO model. Furthermore, there is an obvious semiannual variation component while analyzing the NRLMSISEOO data without 130-day-wide sliding window. Thus it is considered that, with the restriction of CHAMP orbit, the 130-day-wide sliding window may smooth out the semiannual component, as well as the higher. It is concluded that the present results are meaningful in the study of the thermospheric climatology.