首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
文中选了5 个典型活动区, 分析了这些活动区的磁场, 与活动区相应的CMEs, 太阳爆发事件和太阳质子事件我们发现, 对于E ≥10meV 的太阳质子事件有相应的源活动区, 源耀斑和CME; 活动区矢量磁场有剪切, 磁场剪切越强质子事件越强; 多数在质子耀斑发生前出现磁流浮现; 太阳10cm 射电爆发持续时间长文中结果还佐证了Shealy 等的结果: X 射线耀斑的长持续时间与CME 的发生正相关另外,在5 个活动区中, 有三个大耀斑发生前没有明显的磁剪切作为它们的先兆, 它们是非质子源耀斑这是Moore, Hagyard 和Davis 的磁场强剪切是耀斑产生的必要条件的反例  相似文献   

2.
The relations between sunspot numbers and earthquakes (M≧6), solar 10.7 cm radio flux and earthquakes, solar proton events and earthquakes have been analyzed in this paper. It has been found that: (1) Earthquakes occur frequently around the minimum years of solar activity. Generally, the earthquake activities are relatively less during the peak value years of solar activity, some say, around the period when magnetic polarity in the solar polar regions is reversed. (2) the earthquake frequency in the minimum period of solar activity is closely related to the maximum annual means of sunspot numbers, the maximum annual means of solar 10.7 cm radio flux and solar proton events of a whole solar cycle, and the relation between earthquake and solar proton events is closer than others. (3) As judged by above interrelationship, the period from 1995 to 1997 will be the years while earthquake activities are frequent. In the paper, the simple physical discussion has been carried out. These results supported the exploration and studies of some researchers to a certain extent. This work is supported by Foundation of the Chinese Academy of Sciences (major item).  相似文献   

3.
太阳质子事件期间内辐射带质子通量的变化   总被引:1,自引:0,他引:1  
本文介绍风云一号(B)卫星上的宇宙线成份监测器,在1991年1月30日及31目的耀斑期间及其前后几天,对能量在4-23MeV内的内辐射带质子通量的观测结果,并对这些结果做了详细的分析.结果表明,在这两次耀斑及其所产生的太阳质子事件期间,内辐射带质子通量有显著的变化:在磁漂移壳参量L≥1.64的空间,质子通量显著增强,增幅在40%-200%之间;在L=1.30-1.60的空间,质子通量的增强也较为明显,增幅在20%以上;总的变化趋势是,L越大的地方,质子通量的增强就越显著.质子事件之后,内辐射带质子通量又逐渐回复到质子事件之前平衡结构时的水平.  相似文献   

4.
Influence of short-term changes in solar activity on baric (pressure) field perturbations is studied using such characteristics as the Sazonov index (IS), describing the intensity of meridional transfer, the Blinova index (IB), describing the intensity of zonal transfer, and ‘vorticity area index’ (VAI) describing the tropospheric cyclonic perturbations. The epoch superposition method is used to reveal effects of the solar central meridian (CM) passage of active regions, the Forbush decreases (FD) in galactic cosmic rays, and the solar proton (SP) events. The results of the analysis show that influence of short-term changes in the solar activity on baric field perturbations is the most evident in the stratosphere (30 mbar-level). The meridional circulation in case of the FD and SP events begin to increase about 5–7 days before the key date, reaches maximum nearby the key date and decays after the key date. The meridional circulation in case of the solar CM passage of active regions starts to increase after the key date and reaches the maximum by 5–6 days. Fluctuations of baric field within periods of 5–7 days typical of meridional and zonal transfers in troposphere (500 mbar-level) are evidently connected with internal dynamics of the atmosphere, not with the effects of solar activity. VAI characterizing cyclonic activity in the troposphere, shows the striking correspondence to changes of the meridional circulation in the stratosphere. Comparison of changes in the stratospheric perturbations with behavior of the UV irradiance in course of the FD and SP events show their full correspondence at the initial stage of these processes. The conclusion is made that growth of baric perturbations observed in the stratosphere in associations with the FD and SP events before the key date is caused by the solar UV irradiance increase, whereas decay of the baric perturbations after the key date is related to direct influence of the solar energetic corpuscular fluxes on the stratosphere.  相似文献   

5.
日冕物质抛射(Coronal Mass Ejection,简称CME)和共转相互作用区(Corotating Interaction Region,简称CIR)是造成日地空间行星际扰动和地磁扰动的两个主要原因,提供了地球磁暴的主要驱动力,进而显著影响地球空间环境.为深入研究太阳风活动及受其主导影响的地磁活动的时间分布特征,本文对大量太阳风参数及地磁活动指数的数据进行了详细分析.首先,采用由NASA OMNIWeb提供的太阳风参数及地磁活动指数的公开数据,通过自主编写matlab程序对第23太阳活动周期(1996-01-01—2008-12-31)的数据包括行星际磁场Bz分量、太阳风速度、太阳风质子密度、太阳风动压等重要太阳风参数及Dst指数、AE指数、Kp指数等主要的地磁指数进行统计分析,建立了包括269个CME事件和456个CIR事件列表的数据库.采用事例分析法和时间序列叠加法分别对两类太阳活动的四个重要太阳风参数(IMF Bz、太阳风速度、太阳风质子密度、太阳风动压)和三个主要地磁指数(Dst、AE、Kp)进行统计分析,并研究了其统计特征.其次,根据Dst指数最小值确定了第23太阳活动周期内的355个孤立地磁暴事件,并以Dst指数最小值为标准将这些磁暴进一步分类为145个弱磁暴、123个中等磁暴、70个强磁暴、12个剧烈磁暴和5个巨大磁暴.最后,采用时间序列叠加法对不同强度磁暴的太阳风参数和地磁指数进行统计分析.统计分析表明,对于CME事件,Nsw/Pdyn(Nsw表示太阳风质子密度,Pdyn表示太阳风动压)线性拟合斜率一般为正;对于CIR事件,Nsw/Pdyn线性拟合斜率一般为负,这可作为辨别CME和CIR事件的一种有效方法.从平均意义上讲,相较于CIR事件,CME事件有更大的南向IMF Bz分量、太阳风动压Pdyn、AE指数、Kp指数以及更小的Dstmin.一般情况下,CME事件有更大的可能性驱动极强地磁暴.总体而言,对于不同强度的地磁暴,Dst指数的变化呈现出一定的相似性,但随着地磁暴强度的增强,Dst指数衰减的速度变快.CME和CIR事件以及其各自驱动的地磁暴事件有着很多不同,因此,需要将CME事件驱动的磁暴及CIR事件驱动的磁暴分开研究.建立CME、CIR事件及地磁暴的数据库以及获取的统计分析结果,将为深入研究地球磁层等离子体片、辐射带及环电流对太阳活动的响应特征提供有利的帮助.  相似文献   

6.
本文统计了第22 太阳活动周期间(1991 ~1995 年) 发生的25 个太阳质子事件与太阳耀斑及日冕物质抛射(CME) 事件的关系  统计结果表明, 所有的太阳质子事件都与耀斑发生相关, 除2 个质子事件(19941020 和19951020 日发生的太阳质子事件) 与CME发生无关, 其余质子事件也都与CME 相关  值得注意的是, 与质子事件相关的耀斑有16 个是双带耀斑, 其中包括与CME无关的2 个事件的耀斑, 占总数的64 %   上述统计结果证实了无论是太阳耀斑, 还是物质抛射, 它们对太阳质子事件的发生同样起着非常重要的作用  相似文献   

7.
The paper illustrates the opportunities provided by the use of data from Russian satellite experiments (CORONAS and Universitetsky-Tatiana of Meteor series) on the measurement of fluxes and spectra of solar cosmic rays at altitudes of 370–1000 km for simulation of the ozonosphere state. The results of photochemical simulation and observational data analysis showing the influence of solar protons on polar ozonosphere and lower ionosphere in periods of solar proton events (SPE) on November 4, 2001, October 28, 2003, and January 16, 2005 are presented. It is shown that the solar proton action causes ozone depletion in the mesosphere above the polar regions. The strongest depletion (up to 70%) was caused by the SPE that occurred on October 28, 2003.  相似文献   

8.
The paper presents the results of numerical photochemical simulations of the impact of the most powerful solar proton flares during the 23rd solar cycle on the ozonosphere in the polar regions of the Earth. A global 3D photochemical model, CHARM, developed at Central Aerological Observatory (CAO) was used in the simulations. The model introduces an additional source of nitrogen atoms and OH radicals. These components are formed due to the ionization effect of solar protons in the Earth’s atmosphere. The ionization rate was determined from data on proton fluxes measured by GOES satellites. The production rate of additional NO x and HО x molecules per ion pair was based on published theoretical studies. It is shown that the most intense flares in the 23rd solar cycle (2000, 2001, and 2003) destroyed ozone in the mesosphere to a great extent (sometimes completely, for example, during the July 14, 2000, event). It is found that the response of ozone to solar proton events follows a seasonal pattern. For the first time, the long-term effect of solar proton events is identified; it is approximately one year.  相似文献   

9.
Summary The effects of solar proton flares and enhanced solar activity, indicated by intensive radio bursts in the decimetre range, on the Auroral Electrojet (AE) Index at the time these events occurred, are investigated. A significant increase in the level of the AE index was observed after the occurrence of these events.  相似文献   

10.
Using the data on solar proton fluxes measured on board the GOES satellites, the most powerful solar proton events (SPEs) of solar cycle 23 are selected, and ionization rates in the atmosphere in these periods at high latitudes of the Northern Hemisphere are calculated. Assuming that each ion pair formed at the retardation of solar protons in the atmosphere leads to the formation of 1.25 molecules of nitric oxide, 2.0 molecules of the OH radical, and one oxygen atom, changes in the content of ozone, nitrogen and other compounds were calculated using a photochemical model. The calculations showed that the strongest ionization and destruction of ozone was caused by SPEs that occurred on July 14, 2000; November 8, 2000; November 4, 2001; and October 28, 2003. The results can form the basis for compiling the catalog of changes in ionization and ozone in the atmosphere caused by solar proton activity.  相似文献   

11.
With one example of a coronal mass ejection observed with SOHO/EIT and LASCO we demonstrate the main characteristic of this kind of event: its flux rope nature. These events are commonly responsible for magnetic clouds approaching the Earth. Near the solar surface, the different structures expected during the ejection of a flux rope are observed: post flare loops located under the flux rope, a prominence lying at its lower part, a coronal void located at its upper part. Two additional structures are observed in coronal emission: a bright loop possibly located at the leading edge of the flux rope and a bright front located near the equator and moving along the solar limb. These structures may correspond to the compression of material while the flux rope expands. Finally, the deviation of these structures toward the equator is observed, providing the possible explanation of the discrepancy of the location of the activity in the low corona and in the high corona during the minimum of solar cycle activity.  相似文献   

12.
We present a compelling similarity of impulsive nitrate enhancements observed in polar ice from the northern and southern hemispheres. This analysis concentrates on the period 1940–1950, during which time the first four recorded solar cosmic ray ground-level enhancements (GLEs) occurred. GLEs are strong solar proton events. We show that large and sudden enhancements in the nitrate records from both hemispheres were observed within weeks following the recorded solar cosmic ray ground-level event. The observation of impulsive nitrate enhancements simultaneously in both hemispheres shortly after a large fluence solar proton event is strong evidence in support of a causal connection and argues strongly for rapid transport of atmospheric nitrates generated through the polar atmosphere by energetic solar proton events.  相似文献   

13.
Data from meteo radar measurements of the wind in the mesosphere/lower thermosphere region at high latitudes of the Southern Hemisphere (Molodezhnaya station, 68° S, 45° E) and at middle latitudes of the Northern Hemisphere (Obninsk station, 55° N, 37° E) during solar proton events that took place in 1989, 1991, 2000, 2005, and 2012 are analyzed in the paper. In 1989 and 1991, we succeeded in observing the response to solar proton evens at both stations simultaneously. The results show that solar proton events lead to a change in the wind regime of the mesosphere and lower thermosphere. At high latitudes of the Southern Hemisphere, significant changes are observed in the values of the velocities of the meridional and zonal components of the prevailing wind. In the case of powerful solar proton events, the amplitude of the semidiurnal tide grows in the vicinity of the proton flux maximum. The response to these events depends on the season. The reaction of the prevailing wind at middle latitudes shows the same features as the reaction of the wind at high latitudes. However no unambiguous response of the tide amplitude is observed. In the summer season, even powerful events (for example, in July 2000) cause no changes in the wind regime parameters in the midlatitude region of the mesosphere/lower thermosphere.  相似文献   

14.
Based on an analysis of the available archived data from the Russian network of geomagnetic stations, it has been indicated that the known event of August–September 1859 was the first and the greatest event in the series of the recurrent geomagnetic storms. Similar series were repeatedly observed in the next years. These series are caused by the processes on the Sun and in the heliosphere related to the superposition of the solar wind flows. The sporadic and regular components in joint activity of the complex, including active regions and coronal holes on the rotating Sun, play the role of the Bartels M regions responsible for initiation and development of geomagnetic storms. Neither coronal holes nor active regions can separately explain observations. During interpretation, active regions and coronal holes should be considered as a unified complex.  相似文献   

15.
The short-term regional responses of the mesosphere–lower thermosphere (MLT) dynamics over Scandinavia to the exceptionally strong solar storms with their accompanying solar proton fluxes on the Earth in late October 2003 have been investigated using radar measurements at Andenes (69°N, 16°E) and Esrange (68°N, 21°E). Several solar activity storms resulted in solar proton events (SPEs) at this time, but a particularly active period of high proton fluxes occurred between 28 and 31 October 2003. The significant temperature drop (∼25 K), detected by the meteor radar at Andenes at altitude ∼90 km, was in line with the enhancement of the proton fluxes and was caused by the dramatic reduction of the ozone in the high-latitude middle atmosphere monitored by satellite measurements. This exceptionally strong phenomenon in late October 2003 was composed of three geomagnetic storms, with the first one occurring in the daytime of 29 October and the other two storms in the nighttime of 29 and 30 October, respectively. The responses of the prevailing wind and the main tides (24- and 12-h tides) were studied in detail. It was found that the response of the MLT dynamics to the first geomagnetic storm occurring in the daytime and accompanied by solar proton fluxes is very different from those to the second and third geomagnetic storms with onsets during the nighttime. Some physical mechanisms have been suggested in order to explain the observed short-term variability of the MLT dynamics. This case study revealed the impact of the SPEs observed in late October 2003 and the timing of the geomagnetic storms on the MLT neutral wind responses observed over Scandinavia.  相似文献   

16.
Summary On November 1960 a special solar activity occured, producing characteristic disturbances in the ionosphere. Athens center followed this activity by vertical sounding and by Riometer recordings. They are evidences for proton events producing deep absorption in the ionosphere and aurora extending till 38° latitude. Some observations concerning July 1961 solar activity are reported. World wide decrease of the maximum electron density reported during the November period was observed also in Athens. Ionospheric disturbances following vertical sounding observations are of «negative» type.  相似文献   

17.
The catalog of ground level enhancements of solar cosmic rays during cycles 21—23 of solar activity has been presented. The main properties, time distribution, and relation of these events to solar sources and proton enhancements observed on satellites have been studied.  相似文献   

18.
分析了1988~2006年中62个典型的太阳质子事件,发现其归一化后峰值流量变化具有很好的统计规律,根据该规律提出了一种对太阳质子事件峰值流量进行预报的方法.试验预报结果表明,太阳质子事件峰值流量的预报值和实测值都在同一个量级以内,平均相对误差为32%,预报误差在可接受范围内.本文方法对于日常预报业务而言是实用和可行的.  相似文献   

19.
This paper investigates the relationship between cyclic variations in the velocity of coronal mass ejections and cyclic changes in the structure of the large-scale solar magnetic field (LSSMF) in solar cycle 23, using the effective solar multipole index as a parameter of the characteristic dimensions of LSSMF structural elements. Cyclic variations in the velocity and frequency of coronal mass ejections are found to resemble cyclic changes in the effective solar multipole index. It is suggested that cyclic changes in the maximum velocity of coronal mass ejections are associated with different conditions for the formation of complexes of active regions connected by coronal arch structures, the energy of which is the main source of energy (velocity) for coronal mass ejections. The study leads to some suggestions about the possible site of initiation of coronal mass ejections.  相似文献   

20.
We study the annual frequency of occurrence of intense geomagnetic storms (Dst < –100 nT) throughout the solar activity cycle for the last three cycles and find that it shows different structures. In cycles 20 and 22 it peaks during the ascending phase, near sunspot maximum. During cycle 21, however, there is one peak in the ascending phase and a second, higher, peak in the descending phase separated by a minimum of storm occurrence during 1980, the sunspot maximum. We compare the solar cycle distribution of storms with the corresponding evolution of coronal mass ejections and flares. We find that, as the frequency of occurrence of coronal mass ejections seems to follow very closely the evolution of the sunspot number, it does not reproduce the storm profiles. The temporal distribution of flares varies from that of sunspots and is more in agreement with the distribution of intense geomagnetic storms, but flares show a maximum at every sunspot maximum and cannot then explain the small number of intense storms in 1980. In a previous study we demonstrated that, in most cases, the occurrence of intense geomagnetic storms is associated with a flaring event in an active region located near a coronal hole. In this work we study the spatial relationship between active regions and coronal holes for solar cycles 21 and 22 and find that it also shows different temporal evolution in each cycle in accordance with the occurrence of strong geomagnetic storms; although there were many active regions during 1980, most of the time they were far from coronal holes. We analyse in detail the situation for the intense geomagnetic storms in 1980 and show that, in every case, they were associated with a flare in one of the few active regions adjacent to a coronal hole.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号