利用中国地壳运动观测网络的GPS资料对太阳耀斑的监测及分析

利用中国地壳运动观测网络的GPS资料对2000年7月14日的太阳耀斑进行监测和分析,介绍一种值得探讨的耀斑爆发前可能存在的"前兆"现象.     

2021—2050年河南省夏玉米净灌溉需水量对气候变化的响应

基于河南省17个气象站点观测资料和25个CMIP5模式预估数据,采用BCC/RCG-WG 3.0天气发生器构建区域气候变化情景,集合评估了RCP4.5情景下2021—2050年夏玉米净灌溉需水量较1961—2000年的变化及其空间分布。结果表明：全生育期内气温升高1.8℃,降水增加3.6%,引起作物需水量和有效降水量分别增加5.1%和1.5%,净灌溉需水量增加5.6%。受气温升高和降水减少的双重影响,播种－拔节期净灌溉需水量增幅较大,达到21.3%;拔节－乳熟期尽管有效降水量增加3.0%,但这并不足以抵消气温升高引起的作物需水量增加5.1%的影响,净灌溉需水量仍然增加3.4%;乳熟－成熟期,由于有效降水量增加8.2%,超过了作物需水量增加7.4%的影响,净灌溉需水量减少1.4%。豫西三门峡、孟津和豫西南栾川、西峡等4站在各生育期内净灌溉需水量均有不同程度的增加。     

低过冷雨水含量天气过程冰雹形成机制及催化机理模拟1

利用三维全弹性冰雹云模式,对2008年5月24日山东境内一次受高空冷涡影响的大范围冰雹天气过程进行模拟,分析了冰雹的形成机制和催化防雹机理。结果表明:该过程过冷雨水中心位于最大上升气流中心下方,不存在过冷雨累积区,过冷雨水含量最大值仅为4.9gm^-3,但雹云中过冷雨水含量仍然丰富,对雹胚的形成及增长起着重要作用。雹胚以冻滴为主,冻滴胚来源于冰雪晶与过冷雨水碰撞冻结以及雨滴核化过程。冻滴形成后主要以碰并过冷雨水、云水增长。冻滴胚自动转化过程是冰雹数量、质量的主要来源;冰雹形成后,前期主要靠碰并冻滴、霰和过冷雨水增长,后期主要靠碰并过冷云水增长。催化试验表明,播撒57.5g催化剂足以通过"竞争"减雹50%以上,增加AgI剂量,防雹的同时能够兼顾增雨。催化剂用量为230g时,催化后液态降水有所增加,固态降水量及占总降水量的比例减少显著,特别是冰雹。AgI主要以凝华核的作用产生人工冰晶,冰晶凝华增长导致过冷云水、雨水含量降低。催化后雹胚特别是冻滴胚数量增多,对过冷云水、雨水的竞争增强;其平均尺度、质量的减小,降低了向冰雹的转化率。冰雹碰并过冷云水、雨水增长过程被减弱,导致冰雹总质量进一步减少,达到消雹目的。     

AgI焰剂对层状云催化的数值模拟

使用包含详细微物理过程的一维层状云全分档模式,并加入AgI焰剂催化方案,对2007年吉林省长春市一次层状云降水过程进行AgI播撒试验。分别选取云内过冷水含量峰值区(4000 m)、最大冰面过饱和度区(5000 m)和低温度区(5500 m)作为播撒试验区,播撒时间选择云体未充分发展阶段和充分发展阶段。结果显示,在同等播撒剂量下,地面降水对云内AgI播撒高度较为敏感。ST2方案模拟400 min后地面累计降水量增加10.4%。同等条件下,播撒时间越早,催化效果越佳。在充分发展的云体内播撒AgI焰剂,40 min后云内过冷水含水量减少70%以上,表明云内过冷水消耗量与地面雨强增加量之间具有良好的正相关性。4种播撒方案均显示,云内AgI主要靠凝华核化机制产生冰晶,而接触核化机制对AgI核化过程贡献较小。与未催化云体相比,催化后云内冰晶粒子总凝华速率增加明显。同时,地面雨强增加,最大雷达回波强度减小。地面水滴粒子谱分布显示,相比于未播撒时,各播撒方案均使直径400 μm左右的水滴粒子浓度增加1个数量级以上,而水滴粒子谱宽均略有下降,这表明AgI播撒后主要通过增加可降水粒子数量来影响地面降水强度和累计雨量,而对降水粒子谱型拓宽的贡献有限。     

太阳耀斑对电离层天顶方向电子总量的影响

对2000年7月14日太阳耀斑爆发期间北京、武汉、上海3个观测站的GPS数据进行了精化处理,计算出各个卫星交叉点沿天顶方向上的电子总量,并对是否消除仪器偏差的计算结果进行了比较,从时间域、空间域上分析了这次耀斑爆发时电离层电子总量变化的特点。结果表明：利用精化的GPS数据才能更好地反映出太阳耀斑爆发时电离层电子总量的突变情况和变化规律。分析1998年11月22日和2000年7月14日耀斑爆发期间的GPS资料,还发现在耀斑爆发前一天与耀斑爆发相对应的一个时间段内,如果卫星交叉点的运动轨迹是从高纬到低纬的运动,这些交叉点的VTEC(天顶方向上的电子总量)值在该时间段内有迅速增长的异常现象。这是否是耀斑爆发的“前兆”现象,值得进一步研究。     

Sunspot proper motions in active region NOAA 2372 and its flare activity during SMY period of 1980 April 4–13

Solar Active Region NOAA 2372 was observed extensively by the Solar Maximum Mission (SMM) satellite and several ground-based observatories during 1980 April 4–13 in the Solar Maximum Year. After its birth around April 4, it underwent a rapid growth and produced a reported 84 flares in the course of its disc passage. In this paper, we have studied photospheric and chromospheric observations of this active region together with Marshall Space Flight Center magnetograms and X-ray data from HXIS aboard the SMM satellite. In particular, we discuss the relationship of the flare-productivity with sunspot proper motions and emergence of new regions of magnetic flux in the active region from its birth to its disappearance at the W-limb.     

On the transport of magnetic energy and complexity to the solar corona

For the active corona—a system consisting of electromagnetic fields and particles, the only open field surface is the solar photosphere. Interaction between the velocity and magnetic fields on the photosphere is the primary cause of the upward transport of magnetic energy and complexity to the corona, with the diffusion process there also playing a role.     

Spectral Observations of the Flare Star HU Del

Results are presented from a study of 27 spectra of the flare star HU Del obtained during 2000–2002 on the 2.6 meter telescope at the Byurakan Observatory. Two flares were detected, along with a weak correlation between the equivalent widths of the Hα and Hβ emission lines. At the time of the photometric maximum of a flare the equivalent widths of both these lines are minimal and reach their maximum only significantly afterward. A strong increase in the Hβ line intensity is observed which appears to be the consequence of a photometrically undetected, short-duration flare. A possible relationship between the binary (multiple) character and the physical activity of this star is examined briefly in terms of current theoretical models.__________Translated from Astrofizika, Vol. 48, No. 3, pp. 335–348 (August 2005).     

Flares and separatrices between magnetic loops

Time sequences of vector magnetograms of Hauirou and Big Bear Solar Observatories have provided us the opportunity to identify the individual magnetic loops and athe separatrices between them.

Based on the continuous observatin of vector magnetic field of NOAA 7469 from 4 to 12 April 1993, for the first time, the authors have identified the magnetic loop systems and relevant separatrices for such an active region. The observational signature ofthe cross-section of separatrices on the photosphere is as follows:

1. (1) High degree of magnetic shear at or close to the separatrices;

2. (2) Steep gradient of line-of-sight magnetic field ( 0.1 G/km) crossing the neutral line.

3. (3) Flux cancellation from both sides of the separatrices. At this point the transverse field partly changes its alignment.

During the observed period, flare activity took place repeatedly in the vicinity of the separatrices.     

太阳软X射线耀斑与微波爆发的共生关系

本文从SGD上1989年四个大活动区中选取微波爆发和软X射线耀斑(SXR 耀斑>C5级)的相应参量进行统计分析,得到它们之间的相关系数R,一般都有0.9≤|R|<1,从而说明了SXR耀斑同微波爆发之间存在着紧密的共生关系,也证实了耀斑期间由微波爆发源区(磁环顶部)流出的大量非热电子束沿磁环两翼在下倾注到色球层时,因爆发性碰撞加热而引起色球等离子体蒸发,蒸发的高温物质沿磁环上升而发出波长为(1—8A)的SXR 耀斑辐射(10~6K相似文献