JJI甚低频台站信号对太阳耀斑事件的响应特性

太阳耀斑发生时,日地空间的X射线通量会随之增大,进而影响到地球电离层的电子密度分布,导致地球-电离层波导状态发生改变,因此接收到的甚低频（VLF,Very Low Frequency）信号会表现出对应的扰动现象.2017年9月8日,位于湖北省内武汉和随州两站点的VLF接收机分别监测到与X射线太阳耀斑相关的来自日本宫崎县（130°49'E,32°04'N）的JJI甚低频台站信号（22.2 kHz）的振幅异常事件.分析当日的数据发现JJI信号的振幅对不同的太阳耀斑出现不同的响应类型,而且对于同一个耀斑,两地的信号响应类型不尽相同.通过统计2017—2019年间与太阳耀斑相关的JJI信号振幅扰动事件,发现两接收站点的JJI信号响应类型都与耀斑强度及其发生时间存在一定的关系,且呈现出四种响应类型,即两次上升下降型、先上升后下降型、下降型和上升型,但是四种响应类型的事件占比不同.拟合结果表明信号的扰动幅度与X射线通量的积分成正相关,但是两站点的线性拟合斜率存在差异.JJI信号到武汉和随州均属于近似沿纬度方向的短距离传播,且两接收站点相距较近,因此两传播路径大致相似.研究两路径上JJI信号对太阳耀斑响应的差异性有助于理解VLF信号的传播以及探索其在太阳活动监测方面的应用.

     

基于GIS技术江苏省矿产地发布辅助筛选系统设计及应用

矿产地发布辅助筛选系统是以地理信息系统(Geographic Information System,GIS)为基础,利用VB6.0开发而成。系统界面友好,反应速度快,可以直接读取现有的矿产地空间数据库、探矿权数据库、采矿权数据库中的数据进行空间分析,实现了重叠面积、重叠率自动计算,裁剪重叠区后矿产地新范围拐点标注与坐标的自动求取,重叠图自动生成,并用自定义窗体模版直接打印分析结果。     

Extensive serendipitous X-ray coverage of a flare star with ROSAT

We report the serendipitous discovery of a flare star observed with the ROSAT X-ray observatory. From optical spectra, which show strong and variable emission lines of the hydrogen Balmer series and neutral helium, we classify this object as a M3.0Ve star, and estimate a distance of 52 pc from published photometry. Owing to the close proximity of the star (13.6 arcmin) to the calibration source and RS CVn binary AR Lacertae, long-term X-ray coverage is available in the ROSAT archive (∼50 h spanning 6.5 yr). Two large flare events occurred early in the mission (1990 June–July), and the end of a third flare was detected in 1996 June. One flare, observed with the Position Sensitive Proportional Counter (PSPC), had a peak luminosity L _X=1.1×10³⁰ erg s⁻¹, an e-folding rise time of 2.2 h and a decay time of 7 h. This decay time is one of the longest detected on a dMe star, providing evidence for the possibility of additional heating during the decay phase. A large High Resolution Imager (HRI) flare (peak L _X=2.9×10³⁰ erg s⁻¹) is also studied. The 'background' X-ray emission is also variable – evidence for low-level flaring or microflaring. We find that 59 per cent of the HRI counts and 68 per cent of the PSPC counts are caused by flares. At least 41 per cent of the HRI exposure time and 47 per cent of the PSPC are affected by detectable flare enhancement.     

The role of non-thermal electrons in the optical continuum of stellar flares

The continuum emission of stellar flares in UV and visible bands can be enhanced by two or even three orders of magnitude relative to the quiescent level and is usually characterized by a blue colour. It is difficult for thermal atmospheric models to reproduce all these spectral features. If the flaring process involves the acceleration of energetic electrons which then precipitate downwards to heat the lower atmosphere, collisional excitation and ionization of ambient hydrogen atoms by these non-thermal electrons could be important in powering the continuum emission. To explore such a possibility, we compute the continuum spectra from an atmospheric model for a dMe star, AD Leo, at its quiescent state, when considering the non-thermal effects by precipitating electron beams. The results show that if the electron beam has an energy flux large enough (for example, ℱ₁∼10¹² erg cm⁻² s⁻¹), the U -band brightening and, in particular, the U − B colour are roughly comparable with observed values for a typical large flare. Moreover, for electron beams with a moderate energy flux ℱ₁≲10¹¹ erg cm⁻² s⁻¹, a decrease of the emission at the Paschen continuum appears. This can explain at least partly the continuum dimming observed in some stellar flares. Adopting an atmospheric model for the flaring state can further raise the continuum flux, but it yields a spectral colour incomparable with observations. This implies that the non-thermal effects may play the chief role in powering the continuum emission in some stellar flares.     

四川省地质环境状况及地质灾害发育特征研究

四川省是我国地质灾害最多的省份之一,具有点多、面广、规模大、成灾快、爆发频率高、延续时间长的特点.通过对5770个已知地质灾害点的综合研究分析,总结归纳四川省地质灾害的发育规律和特征,建立崩塌、滑坡地质灾害的评判模型,并对全省地质灾害发育强度、地质灾害危险性进行分区评价,提出四川省地质灾害防治体系框架体系及措施,为全省地质灾害的防治工作提供了科学的理论和基础依据.     

2004年1月8日活动区10537内耀斑和相关CME的分析研究

利用色球Hα线心像、TRACEUV和SOHO/EITEUV单色像、SOHO/LASCO白光日冕观测、SOHO/MDI光球磁图以及Nobeyama射电观测,对2004年1月8日日面边缘δ位形黑子群AR10537内发生的一个M1.3耀斑及相关的CME进行了初步的分析。该耀斑除了位于反极性磁场区域、覆盖部分黑子半影的两个主耀斑带外,还伴随有一个明显的远距离耀斑带,这表明有扰动能量沿大尺度日冕结构从耀斑源区向外传播。这一远区增亮处随后有EITdimming出现,表明色球蒸发导致的物质损失可能是产生日冕dimming的重要因素。另外,位于远距离耀斑带南面的一个大宁静暗条在耀斑发生后有部分消失,这可能与该耀斑导致的大尺度日冕磁场重构有关。该耀斑爆发与LASCO观测到的一个快速partialhaloCME在空间和时间上具有密切的关系,它们极可能是相同磁场过程在日冕的不同表现,故我们将此耀斑及与之伴随的日冕dimming认证为这一CME的日面源区。     

The Effect of Relative Sunspot Numbers,Solar Flare Numbers and Variable Component of 10.7 cm Solar Flux on The Seasonal Variation of 6300 Å Line Intensity at Calcutta

The paper presents the seasonal variation of 6300 Å line intensity at Calcutta with relative sunspot number, solar flare number and variable component of 10.7 cm solar flux. A study has been made and important results have been obtained which are as follows. (i) Intensity of 6300 Å line shows periodic variation with relative sunspot number, solar flare number and variable component of 10.7 cm solar flux during the period 1984–1986 which is the secondary peak of the descending phase of 21st solar cycle. (ii) 6300 Å line intensity at Cachoeira Paulista station, taken by Sahai et al. (1988), also shows periodic variation with solar parameters during the period 1978–1980 which is the peak phase of the solar cycle. (iii) A possible explanation of such a type of variation is also presented.     

HY-1C/D CZI多光谱影像云覆盖与耀斑区域绿潮自动提取方法研究

针对多光谱影像受云、雾、太阳耀斑等因素的影响,难以实现高精度的绿潮自动提取的问题,本文以我国的HY-1C/D卫星CZI载荷多光谱影像为数据源,采用数据挖掘技术,通过探索绿潮区域与非绿潮区域的光谱分布差异,提出一种适用于HY-1C/D CZI影像的高精度、全自动绿潮提取方法。首先,分析有云区域和无云区域样本的光谱差异,给出厚云去除规则;其次,选取绿潮和非绿潮区域的样本,采用决策树算法生成绿潮提取规则;然后,针对薄云和厚云边界区域常常会出现误检绿潮的问题,设计了5种错误类别修正策略。为验证方法的有效性,收集2021年黄海区域绿潮暴发周期内的25景HY-1C/D CZI影像,开展绿潮自动检测实验。结果表明,与传统的NDVI方法、VB-FAH方法等指数方法以及ResNet50、U-Net等深度学习方法相比,本文方法在准确度、Kappa系数、F1-Score和MIoU等指标上均优于其他方法,而且能够实现在厚云、薄云、无云、云斑和耀斑区域复杂情况下的绿潮的高精度自动提取。     

普通克立格方法的奇异性问题研究

普通克立格方法是一种广泛应用于各种地质领域的线性插值方法。在普通克立格方法实际应用中,有时会出现方程无解的问题,而这些问题的出现往往与协方差函数的选取以及取样点的空间分布有关。这里通过对协方差函数的严格正定性分析,以及对取样点的空间分布对协方差阵奇异性的影响分析,试图拓展对普通克立格方法奇异性分析的各种思路,从而让人们在普通克立格方法的实际应用中找到奇异性无解的原因,有意识地避免可能发生的奇异性无解问题。     

EFFECTS OF SOLAR FLARE ON THE MIDDLE ATMOSPHERE*

The SME satellite data of solar UV radiation and mesospheric ozone during solar flare in 1982 are analyzed.The results show that the Ha line index used in the solar flare classification is not a proper parameter for studying the effects of solar activity on the photochemical process in the middle atmosphere.