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A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

Science china(Technological Sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2.& FENG Xueshang1,3.1. SIGMA weather Group, Key Laboratory of {2. weather, {3. for {2. Science and Applied Re-search, Chinese Academy of Sciences, Beijing 100080, china 2. Graduate School of the Chinese Academy of Sciences, Beijing 10003., china 3. School of Geophysics and Geoinformation Systems, china University of Geosciences, Beijing 100083. china 1. SIGMA weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. Graduate School of the Chinese Academy of Sciences 100039 Beijing China 3. School of Geophysics and Geoinformation Systems China University of Geosciences 100083 Beijing China

Using 80 CME-ICME events during 1997.1―2.02.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2. The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. {2. The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within {2.% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

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Prediction method for October 2.03.solar storm

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Science china(Technological Sciences) 2006年第5期49卷 629-640页

作者： XIE Yanqiong1, 2. 3. WEI Fengsi1, FENG Xueshang1 & ZHONG Dingkun1, 2.1. State Key Laboratory of space {2., {2. for space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, china 2. Graduate School, Chinese Academy of Sciences, Beijing 10003., china 3. Institute of Meteorology, PLA University of Science and Technology, Nanjing 2.1101, china State Key Laboratory of space weather Center for Space Science Applied Research Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100039 China Institute of Meteorology PLA University of Science Technology Nanjing 211101 China

Aiming at two intense shock events on October 2. and 2., 2.03. this paper presents a two-step method, which combines synoptic analysis of space {2. ——“observing” and quantitative prediction ——“palpating”, and then uses it to test predictions. In the first step of “observing”, on the basis of observations of the solar source surface magnetic field, interplanetary scintillation (IPS) and ACE spacecraft, we find that the propagation of the shocks is asymmetric relative to the normal direction of their solar sources, and the Earth is located near the direction of the fastest speed and the greatest energy of the shocks. As the two fast ejection shock events, the fast explosion of coronal mass of the extremely high temperature, the strong magnetic field, and the high speed background solar wind are also helpful to their rapid propagation. In the second step of “palpating”, we adopt a new membership function of the fast shock events for the ISF method. The predicted results show that for the onset time of the geomagnetic disturbance, the relative errors between the observational and the predicted results are 1.8% and 6.7%; and for the magnetic disturbance magnitude, the relative errors are 4.1% and 3.1%, re- spectively. Furthermore, the comparison among the predicted results of our two-step method with those of five other prevailing methods shows that the two-step method is advantageous. The results tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction precision.

关键词： solar storm, interplanetary shock, interplanetary scintillation, two-step method, ISF method.

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Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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Science china Earth Sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3.& ZHANG Renhe2.1. Jiangsu Key Laboratory of Meteorological Disaster (KLME), Nanjing Institute of Meteorology, Nanjing University of Informa- tion Science and Technology, Nanjing 2.0044, china 2. State Key Laboratory of Severe {2. (LaSW), Chinese Academy of Meteorological Sciences, Beijing 100081, china 3. {3. Climate center, Chinese Meteorological Administration, Beijing 100081, china 1. Jiangsu Key Laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. State Key Laboratory of Severe weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. national Climate {2. Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-china Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-china Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-china Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-china Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-china Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-china Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-china Peninsula to South china Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-china Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

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Solar release time of solar energetic particles and associated acceleration source in corona

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Chinese Science Bulletin 2008年第2期53卷 161-168页

作者： LE GuiMing1,2.3.4, TANG YuHua1 & HAN YanBen4 1 Department of Astronomy, Nanjing University, Nanjing 2.0093.{2. 2.Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,{2. Meteorological Administration, Beijing 100081,{2. 3.{3. center for space weather,{2. Meteorological Administration, Beijing 100081,{2. 4 {3. Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012.{2. Department of Astronomy Nanjing University Nanjing China Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing China national center for {2. {3. China Meteorological Administration Beijing China national Astronomical Observatories Chinese Academy of Sciences Beijing China

Solar energetic particles (SEPs) are accelerated in corona at an early phase of solar energetic particle events (SEPE). The acceleration mechanism of SEPs in corona can only be inferred from an analysis of multi-band observational data, as the observation of SEPs is usually made around 1AU. In this context, people have investigated spectrums, charge state, solar release time (SRT), and multi-band data of SEPEs, in an attempt to judge the acceleration mechanism of SEPs. The SRT computation of SEPs is an important and commonly used approach to study the acceleration mechanism of SEPs in corona. This paper reviews some important findings concerning the SRT computation of SEPs, and analyzes different merits of each approach for such calculation, based on a range of SEPE case studies. This paper also analyzes and discusses both possible and actual acceleration mechanisms of a number of SEPEs, by calculating the SRT of the SEPEs. Finally, the paper summarizes the possible problems in studying an acceleration mechanism of SEPEs inferred from the SRT of SEP.

关键词：阳光释放时间加速度电晕太阳耀斑

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A comparative analysis on two solar proton events

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Chinese Science Bulletin 2007年第1期52卷 47-51页

作者： LE GuiMing1,2.3.4, HAN YanBen2.& ZHANG YiJun3.1 Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites,{2. Meteorological Administration, Beijing 100081,{2. 2.{2. Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012.{2. 3.Chinese Academy of Meteorological Sciences,{2. Meteorological Administration, Beijing 100081,{2. 4 national center for space weather,{2. Meteorological Administration, Beijing 100081,{2. Key Laboratory of Radiometric Calibration and Validation for EnvironmentalSatellites China Meteorological Administration Beijing 100081 China

This paper presents a comparative analysis on the two Solar Proton Events (SPE), which occurred on 14 July 2.00 (Bastille Day) and 2. October 2.03.(2.OCT03. respectively. It is found that although the peak flux of the latter seemed to be greater than that of the former based on geostationary observations, the maximum intensities of the energetic protons (>10 MeV and 3. MeV) during the Bastille Day event were all higher than those of the 2.OCT03.event according to the interplanetary observations. Further analysis indicated that the quantity of the seed particles, which could be accelerated to the energies exceeding 10 and 3. MeV by the Coronal Mass Ejection (CME)-driven shock on 14 July 2.00, was far larger than that of the 2.OCT03.event. In the Bastille Day case, when the CME approached to the height around 14 R⊙, the CME-driven shock would reach its maximum capacity in accelerating the solar en- ergetic protons (>100 MeV). In contrast, on 2. October 2.03. when CME approached to the height about 58R⊙, the CME-driven shock reached its highest potential in accelerating the solar energetic protons of the same category. At this moment, the peak flux (>100 MeV) was about 155 pfu, which was much lower than 3.5 pfu measured on 14 July 2.00. This demonstrated that in the Bastille Day event, the quantity of the seed particles, which could be accelerated to the energy beyond 100 MeV, was significantly larger than its counterpart in the 2.OCT03.case. Therefore, the peak flux of an SPE event depends not only on the interplanetary intensity of the solar energetic particles, but also on the velocity of the associated CME-driven shock, and the quantity of the seed particles as well as on the interplanetary magnetic en- vironment. This paper also reveals that the magnetic sheath associated with ICME on 2. October 2.03.captured a large number of solar energetic protons, including those having energy greater than 100 MeV.

关键词：太阳质子 CME 太阳耀斑太阳系

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Electron microscopy study of the sakhaite from endogenous borate deposit in Hunan, china

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Science china Earth Sciences 2004年第3期47卷 232-238页

作者： LIU Xiangwen1,2. YANG Guangming2. ZOU Huamin3. QU Jing1 & ZHAO Wenxia4 1. Graduate School, china University of Geosciences, Wuhan 43.074, china 2. Test {2., china University of Geosciences, Wuhan 43.074, china 3. Physics and Technology College, Wuhan University, Wuhan 43.072. china 4. Test {2., Zhongshan University, Guangzhou 5102.5, china china Univ Geosci Grad Sch Wuhan 430074 Peoples R China china Univ Geosci Test Ctr Wuhan 430074 Peoples R China Wuhan Univ Phys & Technol Coll Wuhan 430072 Peoples R China Zhongshan Univ Test Ctr Guangzhou 510275 Peoples R China

Sakhaite specimens from an endogenous borate deposit in Hunan Province, china have been studied in detail by means of transmission electron microscopy (TEM). The selected area electron diffraction (SAED) patterns obtained with different crystal zone axes show that the crystal system is cubic, with a = 1.463.nm. The convergent beam electron diffraction (CBED) patterns indicate that the point group and {2. group of sakhaite is m3. and Fd3., respec-tively. The {2. group of synthetic sakhaite determined by Chichagov (1974) is F413.. The possible reasons why the {2. groups of the natural and the synthetic sakhaites are different are discussed.

关键词： sakhaite, space group, convergent beam electron diffraction (CBED).

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Nonlinear interactions between gravity waves and background winds

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Progress in Natural Science:Materials International 2007年第6期17卷 639-644页

作者： Liu Xiao1,2.and Xu Jiyao1(1. State Key Laboratory for space weather, {2. for space Science and Applied Research, Chinese Academy of Sciences, Beijing 100080, china 2. Graduate University of Chinese Academy of Sciences, Beijing 10003., china) [a]State Key Laboratory for space weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China [b]Graduate University of Chinese Academy of Sciences Beijing China

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.

关键词： gravity waves background winds vertical group velocity vertical wavelength nonlinear interactions.

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Re-Os(ICP-MS)dating of the massive sulfide ores from the Jinchuan Ni-Cu-PGE deposit

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Science china Earth Sciences 2005年第10期48卷 1672-1677页

作者： YANG Gang1,2. DU Andao1, LU Jiren3. QU Wenjun1 & CHEN Jiangfeng2.1. national Research {2. of Geoanalysis, Beijing 10003.,{2. 2. Laboratory for Earth Material Cycling, School of Earth and {3. Sciences, University of Science and Technology of{2., Hefei 2.0}02.,{2. 3. Institute of Mineral Resource, Chinese Academy of Geological Sciences, Beijing 10003.,{2. national Research center of Geoanalysis Beijing{2. Laboratory for Earth Material Cycling School of Earth and Space Sciences University of Science and Technology of China Hefei China Institute of Mineral Resource Chinese Academy of Geological Sciences Beijing china

Massive sulfide ore from the Jinchuan Ni-Cu-PGE deposit was dated by Re-Os technique using Carius Tube digestion, Os distillation, Re extraction by acetone and ICP-MS measurement. An isochron giving an age of 83. ± 3. Ma, initial 187Os/188Os ratio of 0.2.9 ± 0.018 (MSWD = 1.7) and γOs = 13. ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 82. ± 8 Ma (n=5, MSWD = 4.3.. The result suggests that the deposit was formed at Neoproterozoic and that the formation of the Jinchuan Ni-Cu-PGE sulfide deposit may be closely related to the plume activity, which were attributed to the breakup of the Rodinia supercontinent. The high γOs of the massive ores sug-gests that crustal material was involved in the formation of the Jinchuan deposit, however, the quantity of the added crustal material is less than 10%.

关键词： Jinchuan Ni-Cu-PGE deposit, Re-Os dating, ICP-MS.

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Simulation studies of high-latitude magnetospheric boundary dynamics

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Science china(Technological Sciences) 2004年第4期47卷 421-435页

作者： PU Zuyin1, SHI Quanqi1,3. XIAO Chijie1, FU Suiyan1, ZHANG Hui1,2. ZONG Qiugang2.& LIU Zhenxing3.1. School of Earth and {2. Sciences, Peking University, Beijing 100871, china 2. {2. for {2. Physics, Boston University, 72. Commonwealth Avenue, Boston, MA 02.15, USA 3. {2. for {2. Science and Application Research, Chinese Academy of Sciences, Beijing 100080, china 1. School of Earth and space Sciences Peking University 100871 Beijing China 2. center for space Science and Application Research Chinese Academy of Sciences 100080 Beijing China 3. center for {2. Physics Boston University 725 Commonwealth Avenue 02215 Boston MA USA

Magnetic reconnection at the high-latitude magnetopause is studied using 2.5-dimensional Hall-MHD simulation. Concentric flow vortices and magnetic islands appear when both Hall effect and sheared flow are considered. Plasma mixing across the magnetopause occurs in the presence of the flow vortices. Reconnected structure generated in the vicinity of the subsolar point changes its geometry with increasing flow shear while moving to high latitudes. In the presence of flow shear, with the Hall-MHD reconnection a higher reconnection rate than with the traditional MHD is obtained. The out-of-plane components of flow and magnetic field produced by the Hall current are redistributed under the action of the flow shear, which makes the plasma transport across the boundaries more complicated. The simulation results provide some help in understanding the dynamic processes at the high latitude magnetopause.

关键词： magnetopause, entry layer, magnetic reconnection, vortex reconnection, Hall effect, flow shear.

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Study on NDVI-T_s space by combining LAI and evapotranspiration

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Science china Earth Sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2.3. WANG Pengxin4, YANG Hua1,2.3. LIU Shaomin1,2.3.& WANG Jindi1,2.3.1. Research center for Remote Sensing and GIS, School of Geography, Beijing Normal University, Beijing 100875, china 2. State Key Laboratory of Remote Sensing Science, Beijing 100875, china 3. Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, Beijing 100875, china 4. Department of Information Management, College of Information and Electronic Engineering, china Agricultural University, Beijing 100083. china 1. Research center for Remote Sensing and GIS School of Geography Beijing Normal University Beijing 100875 China 2. State Key Laboratory of Remote Sensing Science Beijing 100875 China 3. Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities Beijing 100875 China 4. Department of Information Management College of Information and Electronic Engineering China Agricultural University Beijing 100083 China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

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