本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证...本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.展开更多
Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by l...Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.展开更多
文摘利用全球导航卫星系统(Global Navigation Satellite System,GNSS)双频差分信号进行电离层电子含量反演是一种常用的电离层探测手段,但GNSS信号在强电磁干扰环境下,被淹没于电磁噪声中而无法被提取,影响电离层总电子含量(total electron content,TEC)反演系统的可靠性。采用传统调零抗干扰阵列天线方案能解决干扰源剥离的问题,但调零信号的天线相位中心不稳定导致高精度的相位平滑伪距和精密单点定位(precise point positioning,PPP)算法无法收敛。针对强干扰环境下的电离层监测需求,本文提出一种抗干扰TEC数据反演手段,通过对阵列天线通道幅相一致性进行校正,保证相位中心的稳定性,从而推算出准确的电离层TEC信息,提高了系统的可靠性和抗干扰能力。
文摘本文研究了2000年10月5日磁暴主相两个不同时段期间环电流的变化速度与相应太阳风参数的关系.研究发现,磁暴主相期间环电流的变化速度并不取决于行星际磁场南向分量的平均值和最大值,也不取决于太阳风电场的平均值和最大值.本文的研究证明,磁暴环电流增强期间环电流的变化速度,不仅取决于行星际磁场南向分量和太阳风的速度,还取决于太阳风的动压,而且太阳风的动压起着非常重要的作用.研究还发现,采用Burton et al.(1975)方程和O′Brien,McPherron (2000a)方程估算得到的2000年10月5日的两次地磁活动的强度远低于实际的观测值.
基金supported by the NSFC (42374204, 42004143,42364012)the Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences (Grant No.YSBR-018)+3 种基金the Scientific Projects of Hainan Province(KJRC2023C05, ZDYF2021GXJS040)the Innovational Fund for Scientific and Technological Personnel of Hainan Provincethe Chinese Meridian ProjectPandeng Program of National Space Science Center,Chinese Academy of Sciences
文摘Physical and chemical processes observed in the mesosphere and thermosphere above the Earth’s low latitudes are complex and highly interrelated to activity in the low-latitude ionosphere.Metallic sodium detected by lidar can yield clues to dynamic and chemical processes in these spatial layers above the Earth’s atmosphere.This paper is based on sodium layer data collected at two low-latitude stations,one in the northern hemisphere and one in the southern.The low-latitude sodium layer exhibits conspicuous seasonal variations in shape,density,and altitude;these variations are similar between Earth’s hemispheres:sodium layer density at both stations reaches its seasonal maximum in autumn and minimum in summer.However,maximal Na density over Brazil is greater than that over Hainan.Nocturnal variations of Na density above the two low-latitude stations are also similar;at both,maxima are observed before sunrise.Some variations of the Na layer over Brazil that differ from those observed in the northern hemisphere may be related to the South Atlantic Magnetic Anomaly(SAMA)or fountain effect.We suggest that low-latitude Na layer data may provide useful additional evidence that could significantly improve the low-latitude part of the WACCM-Na model.
