太阳耀斑的行星引潮力触发

阐述了太阳潮波动力学的概况，依据实际资料的统计结果指出；行星引潮力触发耀斑的效应随耀斑级别的增大而增强；对于3级及其以上耀斑，强潮汐触发较之弱触发的耀斑产出率之比高达9.33；这个重要事实在预报地球和日地空间灾害性扰动方面，会有相当大的实际价值。     

太阳质子耀斑的一个统计性质

本文研究太阳质子耀斑相对于太阳光球大尺度平均磁场中性线的分布, 给出一个新得到的质子耀斑的统计性质。研究太阳质子事件及其源耀斑的统计性质, 是太阳物理和空间物理学的重要前沿课题。从太阳活动预报及地球空间环境预报研究的角度看, 一个重要的问题是质子耀斑在      

基于太阳10.7 cm射电流量的全日面耀斑预报方法

太阳耀斑是一种重要的太阳爆发活动现象,表现为近乎全波段的电磁辐射增强。统计表明,太阳活动水平越高,太阳爆发越频繁,耀斑爆发的概率越大。利用1975-2007年10.7 cm流量与耀斑爆发的统计关系,建立了一种可行的全日面爆发耀斑概率的预报方法,能够实现C,M,X三种级别的耀斑在全日面爆发的概率预报。通过2008-2016年的观测数据,对模型进行了预报性能的评估,得到模型对C,M,X级耀斑发生概率的预报误差均较小,Brier评分误差分别为0.113,0.087,0.012;模型的预报性能均比平均模型有提高,对C,M,X级耀斑发生概率预报的Brier技巧评分分别为0.250,0.106,0.012。在2008-2016年未来1天耀斑预报的模型实测中,模型的预报效果与中国科学院空间环境预报中心的预报效果相当,这说明该模型在实际的空间环境预报中切实可行。     

空间太阳物理学科发展战略研究

太阳物理学是研究太阳上发生的物理过程及其对行星际空间环境影响的学科。太阳是人类唯一可以进行细致探测的恒星，也是天然的多尺度过程并存的等离子体实验室，同时，太阳活动直接影响日地空间环境和人类地球家园的宜居性，剧烈的太阳活动如耀斑和日冕物质抛射还会影响人类的航天航空、通信导航、电网等高技术活动与设施。因此对太阳物理的研究不仅是理解浩瀚宇宙的基石，也是理解日地联系和行星宜居性的基础，同时还是国家在航天和空间安全领域的战略需求。21世纪以来，随着卫星探测技术发展，太阳物理学进入了全新的发展阶段。本文梳理了近年来太阳物理学在空间探测中的发展态势，凝练中国太阳物理学未来空间探测发展的重点领域，优化学科布局，推进太阳物理的高质量发展。     

影响地球环境的太阳质子事件的时间过程

利用1966年以来的大量太阳耀斑以及相应质子事件的资料,分析研究了质子事件到达时间和极大时间同耀斑经度位置的统计关系.结果表明当耀斑位置处于经过地球的行星际大尺度场磁力线足点位置附近时,上述两种时间过程最短.这个结果支持了太阳耀斑粒子经日冕传播再向行星际空间传播的二阶段传播模型.      

基于PCA方法对太阳活动区主要参量的分析

太阳耀斑与太阳质子事件的发生通常与太阳活动区存在非常密切的关系, 对这种关系的深入分析有助于太阳耀斑和太阳质子事件预报模型的建立. 本文利用主成分分析(Principal Component Analysis, PCA)方法对1997-2010年太阳质子事件所在活动区的主要参量进行分析, 选取的参量包括黑子磁分类、 McIntosh分类、太阳黑子群面积、10.7 cm射电流量、耀斑指数、质子耀斑位置和软X射线耀斑强度. 结果得到81个太阳活动主成分得分值排序(得分值代表每个事件的强弱), 与太阳质子事件峰值流量、太阳黑子年均值以及10.7 cm射电流量年均值的对比显示相似度非常高, 表明主成分得分值一定程度上可以反映太阳活动的强弱规律.      

太阳微波爆发动态频谱仪

介绍了北京天文台已投入观测的1.0—20GHz,2.6—3.8GHz太阳射电频谱仪及1999年投入观测的5.2—76GHz太阳射电频谱仪。它们是第23周太阳活动峰年我国太阳物理界的重要观测设备已投入观测的频谱仪获得不同类型的太阳射电爆发资料分别为171个和146个,这些事件在时间和频率上有丰富的幅度和结构的变化。不同太阳射电爆发反映太阳大气不同高度上耀斑的时间和空间的演化过程,为研究不同大气高度中耀斑物理动力学过程、能量释放、粒子加速提供了更多的依据。      

一种新的太阳质子事件警报方法的探讨

本文分析了第21太阳活动周后半期的太阳质子耀斑硬X射线辐射资料, 发现它们的峰值流量、积分流量、上升沿斜率、X光子的最高能量和持续时间等物理参数之间有着不同于非质子耀斑的相关性。据此, 本文采用模糊聚类分析法, 对21太阳活动周期间(1980.2—1986.2)的质子事件进行预报试验。其报准率为88.5%, 虚报率为53.1%, 漏报率为11.5%。本文提供了基于X射线辐射特征的太阳质子事件警报的新途径和方法。      

再次咆哮的太阳

每隔11年,太阳的活动性就会达到一个高潮:几乎每天都会在太阳黑子的附近发生耀斑爆发,带着数十亿吨的磁性气体,飞离太阳,冲向各大行星。几乎遍布整个太阳系的太阳磁场,也会变得十分不稳定而且出现扭曲。这就是太阳活动峰年。 这一轮太阳活动周期在2000年中期达到最高峰,太阳黑子相对数大大超过以往的10年,各种     

太阳质子事件警报

采用人工神经网络预报方法,利用太阳耀斑的日面位置、X射线辐射的峰值流量及其上升时间、2695MHz和8800MHz微波辐射的半积分流量等5个物理参量,提出了一个新的太阳质子事件警报方案,预报太阳质子事件的发生及其流量和时间．该方案在本文检验中达到93．75％的预报准确率．     

武汉上空中层和低热层大气潮汐的流星雷达观测

武汉流星雷达是2002年元月建成的我国第一部全天空流星雷达，本文对2002年2月19日到7月31日流星雷达观测的潮汐的讨论表明，武汉中层顶以周日潮汐为潮汐运动的主要分量，它的强度远大于半日潮汐，周日潮汐和半日潮汐的波源都在80km以下．周日潮汐分量在3、4月份最强，并且经向分量略强于纬向分量．两个分量的峰值在约95km处出现，分别达到44m／s和60m／s．半日潮的最大值24m／s出现在4月初约93km处．周日潮汐和半日潮汐的振幅和相位随时间呈现出拟周期变化的特征，这可能是潮汐与行星波非线形相互作用的结果．观测结果与GSWM模型的比较表明，GSWM模型在相位随高度变化趋势上与观测结果一致，但模型的周日潮相位比观测约超前1—2h，半日潮相位约滞后1—4h．在周日潮汐较强的月份，模型与观测有较大的差异，观测的幅度通常在95km附近有极大值，而模型并没有极大值．GSWM模型对半日潮的幅度的估计通常过小，观测的半日潮汐幅度有时甚至超过模型值的一倍以上．     

Early winter meteor wind over Bologna (45°N, 11°E)

The Bologna meteor radar was operational during two winter campaigns, from 6 January 1982 to 1 February 1982 and from 10 December 1982 to 2 February 1983. As occurrence of minor stratospheric warmings has been reported for these intervals, possible effects on meteor wind over Bologna related to this kind of warming are pointed out. Zonal and meridional prevailing winds are found to exhibit the maximum peak to peak value in their oscillations when a minor stratospheric warming reaches such an intensity that ΔT_{(90°N–60°N)} at 10 mbar is reversed. Diurnal and semidiurnal tides exhibit usual amplitude variations, but the semidiurnal tide has a noticeable phase shift at the time of a minor warming occurrence, while a similar shift is less evident in the diurnal tide phase.     

Integrating Non-Tidal Sea Level data from altimetry and tide gauges for coastal sea level prediction

The main objective of this paper is to integrate Non-Tidal Sea Level (NSL) from the joint TOPEX, Jason-1 and Jason-2 satellite altimetry with tide gauge data at the west and north coast of the United Kingdom for coastal sea level prediction. The temporal correlation coefficient between altimetric NSLs and tide gauge data reaches a maximum higher than 90% for each gauge. The results show that the multivariate regression approach can efficiently integrate the two types of data in the coastal waters of the area. The Multivariate Regression Model is established by integrating the along-track NSL from the joint TOPEX/Jason-1/Jason-2 altimeters with that from eleven tide gauges. The model results give a maximum hindcast skill of 0.95, which means maximum 95% of NSL variance can be explained by the model. The minimum Root Mean Square Error (RMSe) between altimetric observations and model predictions is 4.99 cm in the area. The validation of the model using Envisat satellite altimetric data gives a maximum temporal correlation coefficient of 0.96 and a minimum RMSe of 4.39 cm between altimetric observations and model predictions, respectively. The model is furthermore used to predict high frequency NSL variation (i.e., every 15 min) during a storm surge event at an independent tide gauge station at the Northeast of the UK (Aberdeen).     

北京上空冬季潮汐波活动特征全天时激光雷达探测研究

利用北京延庆子午工程激光雷达对北京上空钠层进行长期连续观测,分析研究钠层及其相关参数的周日变化.提取钠层各个高度上的相位信息,与同时段经向风潮汐信息进行比较发现:在各个高度上,二者周日相位数值基本一致.半日相位对比结果表明,虽然存在差异,但整体仍保持较好的一致性.此外,从2014年至2016年每年10月到第二年1月共4个月的钠层连续观测数据中提取钠层周日和半日的振幅和相位,探究北京上空冬季的潮汐特征.结果显示:周日潮的相位自上向下传播,且无明显的季节变化特征,其垂直波长在40～50km的范围;周日潮较强,半日潮较弱.      

Global structure,seasonal and interannual variability of the eastward propagating tides seen in the SABER/TIMED temperatures (2002–2007)

The present paper is focused on the global spatial (altitude and latitude) structure, seasonal and interannual variability of the most stable in amplitude and phase eastward propagating diurnal and semidiurnal tides with zonal wavenumbers 2 and 3 derived from the SABER/TIMED temperatures for full 6 years (January 2002–December 2007). The tidal results are obtained by an analysis method where the tides (migrating and nonmigrating) and the planetary waves (zonally travelling, zonally symmetric and stationary) are simultaneously extracted from the satellite data. It has been found that the structures of the eastward propagating diurnal tides with zonal wavenumbers 3 and 2 change from antisymmetric with respect to the equator below ∼85 km height, to more symmetric above ∼95 km. The seasonal behavior of the DE3 is dominated by annual variation with maximum in August–September reaching average (2002–2007) amplitude of ∼15 K, while that of the DE2 by semiannual variation with solstice maxima and with average amplitude of ∼8 K. These tides revealed some interannual variability with a period of quasi-2 years. The seasonal behavior of the eastward propagating semidiurnal tide with zonal wavenumber 2 in the southern hemisphere (SH) is dominated by annual variation with maximum in the austral summer (November–January) while that in the northern hemisphere (NH) by semiannual variation with equinoctial maxima. The SE2 maximizes near 115 km height and at latitude of ∼30° reaching an average amplitude of ∼6 K. The seasonal behavior of the eastward propagating semidiurnal tide with zonal wavenumber 3 in both hemispheres indicates a main maximum during June solstice and a secondary one during December solstice. The tide maximizes near 110–115 km height and at a latitude of ∼30° reaching an average amplitude of ∼4.8 K in the SH and ∼4 K in the NH. The tidal structures of the two eastward propagating semidiurnal tides are predominantly antisymmetric about the equator.     

A comparison of seasonal variations of sea level in the southern Baltic Sea from altimetry and tide gauge data

In this paper, seasonal sea level variations have been determined at five locations in the Baltic Sea from satellite altimetry for the period 1993–2015. The results were compared to tide gauge water level data. Annual and semi-annual amplitudes have been investigated for both sea level anomalies and tide gauge water level. It was found that the two independent observations of sea level variations along the Polish coast are in good agreement both in terms of their annual and semi-annual amplitudes and their annual and semi-annual phases. The annual cycles in the sea level variations measured by altimetry and tide gauge reach maximum values at approximately the same month (November/December).Moreover, this article shows the differences between the annual and semi-annual amplitudes and phases in the sea level anomalies and water level data within the same time frame. The difference in the annual amplitudes between the satellite altimetry and the tide gauge results is between 0.33?cm and 1.53?cm. The maximum differences in the annual cycle of the sea level changes were found at the Swinoujscie station. The correlations between the original series and the calculated curves were determined, and the relationship between the amplitudes and the phases were investigated. The correlation between the annual variations observed from the two independent observation techniques is 0.92.To analyse the dynamics of the change in sea level, the linear trend was estimated from the satellite altimetry and tide gauge time series both in the original time series of the data and in the time series in which seasonal variations were removed. In addition, we calculated the estimated errors of regression and how many years’ worth of data are needed to obtain an accuracy of 0.1?mm per year. The estimated errors of regression showed that to get an accuracy of 0.1?mm per year, we need 100?years of data.     

极区夏季中间层半日潮汐的VHF雷达观测

采用德国SOUSYVHF雷达观测数据,研究了极区夏季中间层半日潮汐的结构和变化特征.纬向和经向风的动态Lomb-Scargle谱表明,半日潮是中间层高度上占支配地位的波动,其谱峰对应的频率一般与1/12c·h-1有偏离,说明它们经常处在被扰动状态.稳定的半日潮振幅随高度增加而迅速增长,在87.9km高度附近达到饱和;经向分量的相位一般比纬向分量的相位超前π/4-π/2,从而水平扰动速度矢量端点随时间变化的轨迹显示出顺时针方向旋转的特征.半日潮汐特征参量在纬向和经向风中随时间的变化在基本趋势一致的基础上显示出一定程度的各向异性.      

中纬度冬季低热层潮汐非线性相互作用的MF雷达观测

采用武汉(30°N,114°E)MF雷达在2001年冬季的风场观测数据研究中纬度低热层大气潮汐之间的二阶非线性相互作用.经向风场的Lomb-Scargle归一化振幅谱表明,周日、半日和8 h潮汐是中纬冬季中层顶区域占优势的大气扰动;此外6 h潮汐也清晰可见.双相干谱分析揭示大多数显著的双相干谱峰代表潮汐谐振分量之间的相位互相关或单个潮汐分量的自相关.对随时间变化的潮汐垂直波长的比较发现,实际观测的8h潮汐垂直波长与假定的由观测的24 h潮汐和12 h潮汐非线性相互作用产生的8 h潮汐的理论垂直波长具有明显的一致性.在94.0～98.0km高度范围,周日、半日和8h潮汐之间不仅存在明显的相位相关和垂直波数相关,且它们的振幅随时间变化也显示出振荡幅值相近、振荡相位同步或反相的相关性,表明它们之间已经发生了二阶非线性相互作用.但是在94.0 km以下,三个潮汐分量之间的各种相关性随高度的下降变得越来越弱,因此潮汐二阶相互作用更可能是一种局地和暂态的现象.      

大气中层顶区域波相互作用的一个观测个例

利用SOUSY VHF雷达的观测数据分析了极区中层顶83.4-91.2km范围内大气风场波动的非线性相互作用。大气风场的谱在不同高度上均有明显的潮汐分量峰值，纬向风分量中35h波、半日潮和8.9h惯必重力波构成共振相互作用对，经向风分量中33h波、半日潮和19h惯性重力波构成共振相互作用对。双谱分析表明，这些共振对在许多高度上都发生耦合，35h或33h波振幅的极小值与半日潮的极大值出现的高度几乎相同，呈现出明显的非线性相互作用在空间上不是局域的，而是存在于中层顶区域的几乎所有高度上，这种相互作用不仅导致半日潮振幅随时间的变化，也使半日潮的振幅随空间变化。35h和33h波动可能是在其他时段或其他位置通过行星波与周日潮相互作用产生的，然后传播到观测点并与半日潮发生相互作用。     

Tide variation monitoring based improved GNSS-MR by empirical mode decomposition

Global Navigation Satellite System multipath reflectometry (GNSS-MR) technology has great potential for monitoring tide level changes. GNSS-MR techniques usually extract signal-to-noise ratio (SNR) residual sequences using quadratic polynomials; however, such algorithms are affected considerably by satellite elevation angles. To improve the stability and accuracy of an SNR residual sequence, this study proposed an SNR signal decomposition method based on empirical mode decomposition (EMD). First, the SNR signal is decomposed by EMD, following which the SNR residual sequence is obtained by combining the corresponding intrinsic mode function with the frequency range of the coherent signal. Second, the Lomb–Scargle spectrum is analyzed to obtain the frequency of the SNR residual sequence. Finally, the SNR frequency is converted into the tide height. To verify the validity of the SNR residual sequence obtained by EMD, the algorithm performance was assessed using multigroup satellite elevation angle intervals with measured data from two station, SC02 in the United States and RSBY in Australia. Experimental results demonstrated that the accuracy of the improved algorithm was improved in the low-elevation range. The improved algorithm demonstrated high monitoring accuracy, and the effective number was not less than 80% of the total in SC02, which means it could effectively describe the trend of the tide with accuracy of approximately 10 cm, meanwhile, the RMS error of RSBY could be reduced by 30 cm, to the maximum extent. The EMD method effectively expands the range of available GNSS-MR elevations, avoids the loss of effective information, enhances considerably the utilization rate of GNSS data, and improves the accuracy of GNSS-MR tide level monitoring.