"神舟三号"大气成分探测器探测结果--2002年4月磁暴期间大气成分的异常变化

"神州三号"(SZ-3)大气成分探测器搭载在SZ-3留轨舱上于2002年3月26日发射入轨,正遇2002年4月发生的连续两次地磁扰动事件,SZ-3大气成分探测器测得了轨道舱运行高度上(330-350 km附近)大气成分的响应变化和异常现象.探测数据表明,在地磁扰动期间,不仅发生了大气中主要成分O和N2的数密度值增变的响应变化,而且在进入地磁扰动峰期开始后6h左右在较高纬度处出现了N2的异常增变和O的异常降变.4-5h后,这种异常增变峰和降变谷由纬度42°N左右逐渐推移向纬度较低地区,直至消失.     

"神舟二号"大气密度探测器的探测结果Ⅱ.在太阳和地磁扰动期间高层大气密度的变化

选用了Sz—2大气密度探测器在2001年2—4月间的探测数据,进行日照和阴影区域热层大气密度对太阳和地磁活动程度的响应变化的探讨．结果表明,日照区大气密度峰值主要随F10.7值而变,在地磁扰动期间,阴影区大气密度对扰动的响应更明显,通常响应变化开始于高纬度地区,然后向低纬度地区推移．     

"神舟3号"运行高度上大气密度的变化

"神舟3号"(SZ-3)大气密度探测器搭载在SZ-3留轨舱上于2002年3月发射入轨,在轨运行期间获得了轨道舱运行高度范围(330-410km)内的大气密度数据.数据分析表明,无明显太阳和地磁扰动时,热层大气密度的主要变化之一是日照和阴影区域之间的涨落变化,最大涨落变化比约为3.0,变化比与太阳和地磁活动程度有关.在2002-04-17和2002-04-19的强地磁扰动时,全球热层大气密度上涨,同时在磁扰峰期探测获得30°N-40°N区域出现密度扰动异常现象.对强地磁扰动在运行轨道高度上大气密度最大涨幅约为60%左右,响应过程在时间上要比地磁扰动过程滞后6-7h,日照和阴影区域中大气密度的响应变化程度明显不同.在太阳活动程度发生变化时,热层大气密度会呈现出明显的正相关变化关系.     

强磁暴、能量粒子暴与热层大气密度涨落之间的相关关系

利用1997-2007年由GOES8, GOES11和GOES12星载高能粒子探测器在地球同步轨道高度上所探测到的高能质子和高能电子通量探测数据以及高度560km左右星载大气密度探测器所得的热层大气密度探测数据, 统计分析了强地磁扰动、高能粒子通量跃变和热层大气密度涨落之间的相关关系, 初步获得强地磁扰动期间, 地球同步轨道(外辐射带外环)均出现了增幅大于三个数量级的高能质子通量(尤其是E>1MeV)强增强现象, 随后热 层大气密度强烈上涨, 表明三者之间是正相关关系. 在时间上地球同步轨道高能质子通量强增强现象先于日均Ap值(地磁活动程度)上涨约一天左右, 而热层大气密度强涨落现象又明显滞后于强地磁扰动事件.      

2005年8月24日强磁暴事件对高层大气密度的扰动

对2005年8月24日发生的突发型强磁暴(Kp峰值达到9)事件,利用星载大气密度探测器在轨实时的连续探测数据进行了处理和分析.结果表明,此次强磁暴事件期间,引起560 km高度附近大气密度剧烈扰动,并存在着两种响应过程.一种是跟随地磁扰动程度变化的全球性大气密度涨落变化,响应时间滞后6h左右, 最大涨落变化比为2.5;另一种为磁暴峰期出现在高纬地区的大气密度突发性跃增,增变比高达5.5.后者存在着区域上的不对称性及时间上的突发性和增幅的差异.此次强磁暴峰期还同时出现了南北半球高纬地区的大气密度跃增双峰.同时还表明这种增变峰可能存在着由高纬向低纬地区迅速推移的现象,在中纬地区推移速度可达15°/h(纬度)左右.      

2007-2009谷年期间高热层大气密度的变化

在第23至第24太阳活动周的峰年之间,太阳活动谷年具有持续时间长,极低F_10.7太阳辐射通量（低至65）和超长期的零太阳黑子数记录等特点,因此是观测和研究在这种特殊背景下热层大气变化的极好机会.尤其是能充分理解和掌握在宁静环境下热层大气密度对弱太阳活动和小地磁扰动的响应特性.本文利用高度650 km以上星载大气密度探测器2007—2009年的连续探测数据进行分析,结果表明,在太阳辐射通量F_10.7极低值期间,较高热层大气密度对F_10.7的起伏具有更显著的响应变化.当F_10.7由70降至65时,日均大气密度会有4～5倍的显著降变,远大于通常大气模式中的降变值.同样在F_10.7极低值期间,较高热层大气密度对小地磁扰动也具有显著的响应增变,当日K_p指数之和由23增至30时,较高热层大气密度则会有80%～160%的强增变.     

神舟2号大气密度探测器的探测结果(Ⅰ)日照和阴影区域热层大气密度变化

选用了神舟2号（SZ-2）大气密度探测器在2001年2—4月间的探测数据,进行日照和阴影区域热层大气密度变化的探讨.结果表明:在高度410km附近,日照和阴影区域大气密度变幅为2—3倍,变幅的大小与地磁活动程度呈负相关关系.日照面大气密度峰区位于星下点地方时1400—1500LT的纬度处,峰值大小与太阳活动程度呈正相关关系.阴影面大气密度谷区位于星下点地方时0400-0500的纬度处,同时在±10°纬度区域中还出现了阴影面峰区.     

550～600 km高度上热层大气密度的中长期变化

选用了2005年8月20日至2006年7月28日高度550～600 km附近的热层大气密度探测数据,对表征太阳活动的F10.7值和表征地磁活动强度的Ap指数进行了相关特性的统计.分析结果表明,在无明显地磁扰动时热层大气密度日平均值的涨落呈现27日和准半年的周期性变化,但在地磁扰动期间这种变化的周期性会被削弱,且大气密度的周日变化幅度与F10.7值呈正相关关系.      

中低纬电离层不同季节地磁暴响应的事例分析

利用中国中低纬台站漠河（53.5°N，122.3°E）、北京（40.3°N，116.2°E）、武汉（30.5°N，114.2°E）和三亚（18.3°N，109.6°E）的电离层观测数据，对比分析了4个台站电离层参数在2015年不同季节4个地磁扰动事件期间的变化特征.结果表明，4个磁暴事件期间电离层的响应特征并不完全一致，有着明显的季节特征，春季、夏季和秋季电离层以负相扰动为主，冬季以正相扰动为主.分析发现，中性成分O/N₂的降低与电离层负相扰动有关，但三亚地区的负相扰动还与扰动发电机电场相关.正相扰动的机制在不同事件中并不相同，穿透电场可能是引起春季磁暴事件期间电离层短时正暴效应的原因，而冬季长时间的正暴效应则是扰动电场和中性风共同作用的结果.      

Aura/MLS与TIMED/SABER观测全球重力波特性

大气重力波是临近空间环境主要大气波动之一,对全球环流具有重要影响。卫星上搭载的临边探测器能够探测临近空间大气温度,可用于临近空间大气重力波研究。利用2012－2014年Aura的微波临边探测器（MLS）和TIMED的红外临边探测器（SABER）的探测数据,对20~50 km高度的大气重力波扰动分布特征开展了分析研究,两种观测重力波活动基本一致,重力波随季节、纬度及高度的变化显著。冬季半球高纬度重力波扰动较强,赤道和夏季半球近赤道地区上空也存在明显重力波活动区域,夏季半球高纬度重力波扰动最弱。重力波扰动强度随高度增加。TIMED/SABER重力波扰动强度数值比 Aura/MLS略强。      

SOME RESULTS OF UPPER ATMOSPHERIC COMPOSITION MEASUREMENTS BY A MASS-SPECTROMETER ON BOARD "SZ-2":CHANGE OF COMPOSITIONS DURING SOLAR AND GEOMAGNETIC DISTURBANCES

Upper atmosphere composition data were obtained for the last half year with a quadruple mass spectrometer on board spacecraft "SZ-2" launched on 10 Jan uary 2001. Based on the analysis of these data, the variations of atmospheric compositions in solar and geomagnetic quiet conditions are reported first, then a detailed discussion on the atmospheric composition variations under the so lar and geomagnetic disturbed conditions is given. The results show that near the altitude of 400 km the variations of main atmospheric compositions corre sponding to solar disturbances are more remarkable in the sunlit area than in the shade area. On the contrary, in geomagnetic disturbance events the corre sponding variations are more obvious in the shade area, an evident increase of N2 density at relatively higher latitudes was observed.     

The thermospheric composition different responses to geomagnetic storm in the winter and summer hemisphere measured by “SZ” Atmospheric Composition Detectors

Three “SZ” Atmospheric Composition Detectors (ACDs) on board spacecraft “SZ-2”, “SZ-3” and “SZ-4” were launched on 10th January 2001, 26th March 2002 and 31st December 2002 separately. A large quantity of thermospheric composition data at the orbital altitude ranging from 330 to 362 km were collected from the in-situ measurement of ACDs. The spacecrafts’ lifetime was just in the second peak period of the 23rd solar cycle which includes two peaks and the solar activity value F_10.7 was from 89 to 228. During this period, several intense geomagnetic disturbances happened.     

SZ-5 Cabin's Height Changes during Three Super-storms in 2003

In this work, the daily height variations of SZ-5 (Shenzhou-5) cabin from 22 October to 28 November in 2003 are analyzed, which includes the period of the Halloween Storm and the Great November Storm. The significant orbital decays have been observed at the end of October and in late November due to the great solar flares and the severe geomagnetic storms. According to the equation of the air-drag-force on a spacecraft and the SZ-5 orbital decay information, the relative daily average thermospheric density changes during the three 2003 super-storms are derived and the results are compared with the Naval Research Laboratory Mass Spectrometer Incoherent Scatter Radar Extended Model (NRLMSISE-00). The results show that the daily average thermospheric density (at the altitude of SZ-5, about 350 km) in storm time enhances to approximately 200% as much as that in the quiet time but the empirical model may somewhat underestimate the average thermospheric density changes and the daily contributions of geomagnetic storms to the density enhancements during these severe space weather events.      

CHANGES OF THE THERMOSPHERE DENSITY IN THE SUNSHINE AND SHADE AREA OBSERVED BY "SZ-2" ATMOSPHERIC DENSITY DETECTOR

In this paper, thermosphere density data of "SZ-2" Atmospheric Density Detec tor From February to April 2001 are used to study the changes of the thermo sphere density in the sunshine and shaded area during solar and geomagnetic activity. The results show that in the sunshine area, the peak value of atmo spheric density changes as F10.7 varies; during geomagnetic activity, the peak value of atmospheric density in the shaded area increases as Ap increases, and start off with higher latitude, therefore move to lower latitude.     

Effects of geomagnetic storms on the bottomside ionospheric F region

The geomagnetic storm is a complex process of solar wind/magnetospheric origin. The variability of the ionospheric parameters increases substantially during geomagnetic storms initiated by solar disturbances. Various features of geomagnetic storm act at various altitudes in the ionosphere and neutral atmosphere. The paper deals with variability of the electron density of the ionospheric bottomside F region at every 10 km of altitude during intense geomagnetic storms with attention paid mainly to the distribution of the F1 region daytime ionisation. We have analysed all available electron density profiles from some European middle latitude stations (Chilton, Pruhonice, Ebro, Arenosillo, Athens) for 36 events that occurred in different seasons and under different levels of solar activity (1995–2003). Selected events consist of both depletion and increase of the F2 region electron density. For European higher middle and middle latitude the F1 region response to geomagnetic storm was found to be negative (decrease of electron density) independent on the storm effect on the F2 region. For lower middle latitude the F1 response is weaker and less regular. Results of the analysis also show that the maximum of the storm effect may sometimes occur below the height of the maximum of electron density (NmF2).     

强磁暴期间TIEGCM模式与CHAMP卫星热层大气密度的比较分析

利用NCAR-TIEGCM模式计算了2003年11月20—21日强磁暴期间410km高度上的大气密度,并与CHAMP/STAR加速度计反演数据进行对比和分析. 结果表明,模式结果能够准确反映磁暴期间大气密度的分布和变化情况,与实测结果在变化趋势和量级上具有较好的一致性,但在精细结构和数值大小上仍存在一定差异. 模式低估了磁暴期间大气密度的增幅,实测大气密度增幅高达250%～400%,而模式结果为100%～125%. 模式结果与实测数据的偏差在高纬地区高于低纬地区,日侧高于夜侧. 通过模式和实测数据的分析发现,磁暴期间大气密度扰动具有日夜侧和南北半球不对称性. 此外,模式能够准确反映磁暴期间大气密度扰动从高纬向低纬的传播以及大气密度对SYM-H指数响应的延迟特性.      

Variations of Thermosphere Density Based on Joint Analysis of In-Situ Measurement Data From Shenzhou Spacecrafts

Based on the measurements made by Atmospheric Density Detectors (ADDs) onboard Chinese spacecraft Shenzhou 2-4, the variations of thermosphere density are revealed. During the quiet period, the density at spacecraft altitude of 330～410km exhibited a dominant diurnal variation, with high value on dayside and low value on nightside. The ratio of the diurnal maximum density to the minimum ranged from 1.7 to 2.0. The ratio shows a positive correlation with the level of solar activity and a negative correlation with the level of geomagnetic activity. When a geomagnetic disturbance comes, the atmospheric density at the altitude of 330～410km displayed a global enhancement. For a strong geomagnetic disturbance, the atmospheric density increased by about 56%, and reached its maximum about 6～7 hours after the geomagnetic disturbance peak. The density asymmetry was also observed both in the southern and northern hemisphere during the geomagnetic disturbance peak.