南极陨石研究的启示Ι:早期太阳星云连续化学分馏作用的岩石化学证据

球粒陨石金属相的 Ir、Os、Co等亲铁元素的浓度随氧化程度的升高而显著增大 ,其浓度以及铁纹石 Co含量和橄榄石 Fa值均反映了球粒陨石的氧化 -还原程度具有连续变化的特征。根据铁纹石 Co含量、橄榄石 Fa值、低 Ca辉石 Fs值、金属相的 Ir、Os、Co浓度以及其他球粒陨石分类参数 ,可能存在介于 E与 H、H与 L、L与 L L以及 L L与 C之间的球粒陨石过渡型 ,即E/H、H/L、L/L L和 LL/C化学群 ,从而将原有的 9个球粒陨石化学群增加到 1 3个。球粒陨石氧化 -还原程度的变化特征以及球粒陨石过渡型的发现都表明早期太阳星云的化学分馏作用具有连续变化的特点。     

1989年8月17日耀斑后环系速度场分析

本文给出了１９８９ 年８ 月１７ 日耀斑后环的观测视向速度场,在环内物质在太阳重力、磁场梯度和大气压力梯度联合作用下沿环腿螺旋上升和环内物质密度由环腿向环顶和环足线性递增的假设下,理论上计算了该环系的视向速度场,理论计算和观测结果基本相符,似乎为耀斑物质由色球蒸发作上升运动的观点提供了间接的例证     

乌鲁木齐天文站的耀斑预报

鉴于预报太阳耀斑的重要性和难度,我们在文中介绍了怎样用太阳色球望远镜观测太阳色球层的耀斑先兆（ 现象） ,并且根据太阳活动特点和十几年的观察经验及观测资料,综合分析,判断出太阳色球耀斑将要产生的大概时间,大致规模及耀斑在日面上的可能位置。通过第２２ 周峰年资料验证,准确率可达７０ ％ 。     

A hyperspectral experiment over tropical forests based on the EO-1 orbit change and PROSAIL simulation

ABSTRACT

We designed a unique hyperspectral experiment from the Earth Observing One (EO-1) orbit change to evaluate solar illumination effects over tropical forests in Brazil. Ten nadir-viewing Hyperion images collected over a fixed site and period of the year (July to August) were selected for analysis. We evaluated variations in reflectance and in 16 narrowband vegetation indices (VIs) with increasing solar zenith angle (SZA) from the pre-drift (2004–2008) to the EO-1 drift period (2011–2016). To detect changes in reflectance and shadows, we applied spectral mixture analysis (SMA) and principal component analysis (PCA) and calculated the similarity spectral angle (θ) between the vegetation spectra measured with variable SZA. The magnitude of the illumination effects was also evaluated from change-point analysis and nonparametric Mann-Whitney U tests applied over the time series. Finally, we complemented our experiment using the PROSAIL model to simulate the VIs variation with increasing SZA resultant from satellite drift. The results showed significant changes in Hyperion reflectance and VIs, especially when the EO-1 crossed the study area at earlier times and larger SZA in 2015 (9:05 a.m.; SZA = 59°) and 2016 (8:30 a.m.; SZA = 67°). Compared to the pre-drift period (10:30 a.m.; SZA = 45°), the SZA differences of 14° (2015) and 22° (2016) increased the shade fractions and decreased the vegetation brightness. PCA separated the pre-drift and drift reflectance datasets, showing shifts in scores due to changes in brightness. θ increased with SZA, indicating changes in the shape of the vegetation spectra with drift. For most VIs, the change-point analysis indicated 2015 (SZA = 59°) as the predominant year of detected changes. Compared to the EO-1 original orbit, the Plant Senescence Reflectance Index (PSRI), Anthocyanin Reflectance Index (ARI) and Structure Insensitive Pigment Index (SIPI) presented the largest positive changes during drift, while the Photochemical Reflectance Index (PRI), Visible Atmospherically Resistant Index (VARI) and Enhanced Vegetation Index (EVI) had the largest negative changes. The effect size of the illumination geometry on these VIs was large, as indicated by increasing values of the Cohen’s r metric toward 2016. The anisotropy of the Hyperion VIs was generally consistent with that from PROSAIL in the simulated pre-drift and drift periods. Focusing on structural indices, it affected the relationships between VIs and simulated leaf area index (LAI) at large SZA.     

A relationship between solar activity and frequency of natural disasters in China

The relationship between the length of the solar cycle, a good indicator of long-term change in solar activity, and natural disasters (drought, flood, and strong earthquakes) in China during the last 108 years is analyzed. The results suggest that the length of solar cycle may be a useful indicator for drought/flood and strong earthquakes. When the solar activity strengthens, we see the length of the solar cycle shorten and more floods occur in South China and frequent strong earthquakes happen in the Tibetan Plateau,but the droughts in East China as well as the strong earthquakes in Taiwan and at the western boundary of China are very few. The opposite frequencies occur when the solar activity weakens. The current study indicates that the solar activity may play an important role in the climate extremes and behavior in the lithosphere.     

Geomagnetic Pc3 Pulsations During the Total Solar Eclipse on Aug 11, 1999

The solar eclipse on August 11, 1999, observed in the region covered by many geomagnetic observatories, has offered a unique opportunity to look for an effect of the eclipse on geomagnetic pulsations. The pulsation activity digital data have been taken from Budkov Observatory in the Czech Republic (in the X component only), from observatories in Germany (Niemegk, Fürstenfeldbruck, Bad Bergzabern), in Hungary (Nagycenk), and for comparison in South Africa (Hermanus, conjugate-point station), and in Finland (Sodankylä, far from the eclipse zone). At all these stations the field in all three component has been recorded. The pulsation amplitudes in the X component exhibit a long-term minimum near the time of the eclipse. Spectral analysis of selected short intervals confirmed this decrease and also revealed a decrease of the average pulsation period during the eclipse. Such a change in the amplitude or in the period was not observed outside of the eclipse interval or in other days. Investigation in some narrower frequency bands showed that the maximal decrease occurred in the 15–20 s band. All these changes can be found in records from all the stations near the eclipse totality belt, also in records at the conjugate-point station, where no eclipse occurred. No signature has been found in records at the station situated far from the eclipse zone.     

太阳系早期的短寿期放射性核素

较详细地介绍全新的太阳系起源理论——X-wind模式,天体化学实验发现太阳系早期存在大量的短寿期放射性核素(半衰期小于100Ma),这些核素对太阳系的形成和演化有重要的影响,一种理论认为,这些核素是在恒星内部合成,并由星风注入原太阳分子云,星风产生的激波诱发分子云核的塌缩而形成原太阳,另一种理论认为,这些核素是高能粒子与原太阳分子云或太阳星云中的气体和尘埃相互作用的产物。     

Contributions to the Ring Current Energy During Geomagnetic Storms

The purpose of this research was to study the complexity of the energization of the ring current during a geomagnetic storm, produced during southern Bz(IMF) by the injection of plasma sheet ions, accelerated by enhanced convective electric fields. This model assumes that the plasma sheet is continuously populated by H⁺ from the sun and the ionosphere, and sporadically by ionospheric O⁺, making the ring current a coupled system whose energy can hardly be expressed analytically. When Bz(IMF) turns north, the ring current becomes uncoupled, and the energy decays exponentially if the storm is weak, or can be expressed as a combination of exponentials during strong storms representing the quick decay of O⁺ and the slower decay of H⁺, as has been shown.     

云台太阳光谱仪像质优良的时间分布规律

通过对云台水平式太阳光谱仪 1 982年太阳光谱观测中的成像质量情况统计分析 ,初步得到光谱仪一年中成像质量优良的时间在秋夏 9月和 8月份 ;一天内有两次像质优良的时间 ,上、下午各有一次 ,分别在日出后 2～ 3小时和日落前 3～ 4小时各有半小时到 1小时左右的时间。