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Contribution of tropical cyclone rainfall at categories to total precipitation over the Western North Pacific from 1998 to 2007

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Science China Earth Sciences 2015年第11期58卷 2015-2025页

作者： CHEN FengJiao FU YunFei School of Earth and space Sciences University of Science and Technology of China State Key laboratory of Severe weather Chinese Academy of Meteorological Sciences

Based on 10 years precipitation data from Tropical Rainfall Measurement Mission （TRMM） Multi-satellite Precipitation Analysis （TMPA） 3B42 and the best track data from China Meteorological Administration （CMA）, the seasonal, monthly and annual contribution of tropical cyclone （TC） precipitation to the total rainfall are analyzed over the Western North Pacific （WNP） during 1998 to 2007 from May to December. The results show that：（1） TC seasonal rainfall contribution ranges from 4% in inland regions to above 40% in ocean-regions of 15°N-25°N. TCs at higher categories contribute much more to the total precipitation. （2） On monthly scale, TCs contribute 60% to the total rainfall regionally during whole TC season, which is the maximum contribution. The peak contribution of TC rainfall averaged in multi-months of the ten years occurs in August （28%） over the whole ocean impacted by TC and in December （23%） over the whole land impacted by TC, respectively. （3） On annual scale, the maximum contribution of TC precipitation to the total rainfall are in 2004 （-30%） over ocean and in 1998 （-20%） over land, respectively. （4） The contribution of TC precipitation to the total rainfall increases 6% （decreases 6%） in El Nino （La Nifia） years compared with neutral years.

关键词： tropical cyclone precipitation contribution 3B42 WNP ENSO

Main Science Results from Chinese Meridian Project(2014-2015)

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空间科学学报 2016年第5期36卷 620-625页

作者： WANG Chi State Key laboratory of space weather National Space Science CenterChinese Academy of Sciences

The Chinese Meridian space weather Monitoring Project(Meridian Project for short)is a ground-based geospace monitoring chain in *** consists of a chain of 15 ground-based observatories located roughly along 120°E longitude and 30°N *** observatory is equipped with multiple instruments to measure key parameters such as the baseline and time-varying geomagnetic field,the middle and upper atmosphere and ionosphere from about 20 to 1000 *** project started collecting data in *** a brief overview of the Chinese Meridian Project is given,and most recent science results mainly in the ionospheric and atmospheric studies are presented.

关键词：经络科技成果中医中高层大气空间天气监测地面观测地球监测时变磁场

Investigation of Total Absorption of Radio Waves in High Latitude Ionosphere

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Plasma Science and Technology 2014年第9期16卷 833-836页

作者：史建魁王铮陶伟 G.A.ZHEREBTSOV E.B.ROMANOVA K.G.RATOVSKY State Key laboratory of space weather NSSC/CAS Institute of Solar-Terrestrial Physics SB/RAS Irkutsk 664033 Russia

Using the digisonde data observed at ionospheric station Norilsk （Dip lat. 60~N） in 2006, a statistical study on the characteristics of the ionospheric plasma total absorption of radio waves （IPTAR） was performed. In the winter and some months of equinox, the IPTAR mainly occurred in the nighttime and the highest occurrence rate could be up to 90%. In the summer, the occurrence was relatively low and the differences between nighttime and daytime occurrence reduced. The total duration of IPTAR seemed longer around the winter than that around the summer. The occurrence of IPTAR events ascended as the Kp index increased. The frequent precipitation of energetic particles into the ionospheric plasma in the auroral belt may be the main cause of the IPTAR events.

关键词： ionosphere radio waves total absorption

Properties of Field Aligned Current in Plasma Sheet Boundary Layers in Magnetotail： Cluster Observation

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Chinese Physics Letters 2009年第2期26卷 304-306页

作者：史建魁程征伟 T. L. Zhang M. Dunlop 刘振兴 State Key laboratory of space weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 space Research Institute Austrian Academy of Sciences Graz Austria SSTD Rutherford Appleton Laboratory Chilton Didcot UK

Field aligned current （FAC） distribution in the plasma sheet boundary layers （PSBLs） in the magnetotail is studied statistically by analysing magnetic field data from the Cluster 4-point measurements. The results show that the FAC distribution on the dusk side is not the same as that on the dawn side in the magnetotail. On the each side earthward and tailward, FA C occurrences are different; occurrence and average current density of FA Cs in the northern hemisphere are different from those in the southern hemisphere. This implies that the FACs have dusk-dawn side asymmetry, polarity asymmetry and inter hemisphere difference in the magnetotail. The present results give a good observation evidence for study on the FAC mechanism.

关键词： field emission molybdenum dioxide enhancement factor

Correction of the temperature effect in calibration of a solar radio telescope

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Research in Astronomy and Astrophysics 2021年第6期21卷 349-358页

作者： Li-Hong Geng Cheng-Ming Tan Yi-Hua Yan Bao-Lin Tan Dong-Hao Liu Jin-Ping Dun CAS key laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of SciencesBeijing 100101China School of Astronomy and space Sciences University of Chinese Academy of SciencesBeijing 100049China Key laboratory of space weather National Center for Space WeatherChina Meteorological AdministrationBeijing 100081China

This work analyzes the annual fluctuation of the observation data of the Mingantu Solar radio Telescope(MST)in S,C and X *** is found that the data vary with local air temperature as the logarithmic attenuation of equipment increases with temperature and frequency.A simplified and effective calibration method is proposed,which is used to calibrate the MST data in 2018-2020,while the correction coefficients are calculated from data in *** S,C and X bands,the root mean square errors of one polarization are 2.7,5.7 and 20 sfu,and the relative errors are 4%,6%and 8%*** calibration of MUSER and SBRS spectra is also *** relative errors of MUSER at 1700 MHz,SBRS at 2800 MHz,3050 MHz and 3350 MHz are 8%,8%,11%and 10%*** found that several factors may affect the calibration accuracy,especially at *** method is expected to work for other radio telescopes with similar design.

关键词： instrumentation polarimeters methods data analysis methods:observational

Large solar energetic particle event that occurred on 2012 March 7 and its VDA analysis

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Research in Astronomy and Astrophysics 2016年第8期16卷 33-42页

作者： Liu-Guan Ding Xin-Xin Cao Zhi-Wei Wang Gui-Ming Le School of Physics and Optoelectronic Engineering Institute of Space WeatherNanjing University of Information Science and Technology National Center for space weather China Meteorological Administration

On 2012 March 7, the STEREO Ahead and Behind spacecraft, along with near-Earth spacecraft （e.g. SOHO, Wind） situated between the two STEREO spacecraft, observed an extremely large global solar energetic particle （SEP） event in Solar Cycle 24. Two successive coronal mass ejections （CMEs） have been detected close in time. From the multi-point in-situ observations, it can be found that this SEP event was caused by the first CME, but the second one was not involved. Using velocity dispersion analysis （VDA）, we find that for a well magnetically connected point, the energetic protons and electrons are released nearly at the same time. The path lengths to STEREO-B （STB） for protons and electrons have a distinct difference and deviate remarkably from the nominal Parker spiral path length, which is likely due to the presence of interplanetary magnetic structures situated between the source and STB. Also, the VDA method seems to only obtain reasonable results at well-connected locations and the inferred release times of energetic particles in different energy channels are similar. We suggest that good-connection is crucial for obtaining both an accurate release time and path length simultaneously, agreeing with the modeling result of Wang ＆ Qin （2015）.

关键词： Sun particle emission -- Sun coronal mass ejection (CME) -- method velocity dispersionanalysis (VDA)

WIND observations of plasma waves inside the magnetic cloud boundary layers

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Chinese Science Bulletin 2005年第18期50卷 2051-2056页

作者： WEI Fengsi ZHONG Dingkun FENG Xueshang YANG Fang LIU Rui SIGMA weather Group Laboratory for Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100080 China Graduate School Chinese Academy of Sciences Beijing 100049 China

Based on the WIND observational data for the plasma waves from thermal noise receptor (TNR) working on the frequency 4―256 kHz and the solar wind and the magnetic fields, we analyze the plasma wave activities in the 60 magnetic cloud’s boundary layers (BLs) and find that there are often various plasma wave activities in the BLs, which are different from those in the adjacent solar wind (SW) and the magnetic clouds (MC). The basic characteris-tics are that: (1) the enhancement of the Langmuir wave near the electronic plasma frequency (fpe) is a dominant wave ac-tivity, which occupies 75% investigated samples; (2) the events enhanced both in the langmuir and ion acustic (f space developing space plasma wave theory.

关键词：边界层等离子体波磁场 Langmuir波频率分布

Establishment of N_mF_2 empirical model in the northern hemisphere based on COSMIC occultation data

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Science China(Technological Sciences) 2014年第2期57卷 339-344页

作者： NIU Jun FANG HanXian WENG LiBin Institution of Meteorology and Oceanography PLA University of Science and Technology State Key laboratory of space weather Chinese Academy of Sciences

Ionospheric peak value of F2 layer （NmF2） is an important parameter in the ionosphere, which has important applications in short-wave communication, ionospheric modeling and so on. In this paper, the empirical orthogonal function （EOF） decompo- sition method is used to analyze the NmFz obtained from the occultation data. Daily spatial distribution of NmF2 at the same time is relatively even. Variance of first modal is much larger than the other modals. A local wavelet power spectrum （LWPS） method is applied to analysis the cycle of Flo.7 index and time coefficient of first modal. The result shows that they have simi- lar cycle distribution, indicating that Flo.7 index is the main factor affecting variation of NmF〉 A function is established be- tween the tine coefficient of first modal and F10.7 index, average F10.7 index value of early 81 days fp by least squares method. The results show that contribution coefficient offp is negative which indicates that fp has an inert effect existing in the iono- sphere. Contribution coefficient of F10.7 is positive, which is consistent with the fact that it has an anomaly in winter/spring seasons. In summary, it is feasible to establish a mid-latitude empirical NmF2 model in northern hemisphere based on occulta- tion data and EOF decomposition method.

关键词： empirical NmF2 model empirical orthogonal function decomposition local wavelet power spectrum method least squ-ares method

Diurnal variations of turbulence parameters over the tropical oceanic upper troposphere during SCSMEX

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Science China(Technological Sciences) 2014年第2期57卷 351-359页

作者： LIU Xiao XU JiYao YUAN Wei State Key laboratory of space weather Center for Space Science and Applied ResearchChinese Academy of Sciences College of Mathematics and Information Science Henan Normal University

Using the method of Thorpe analysis, the TKE （turbulence kinematic energy） dissipation rate （e） and turbulence diffusivity （K） were derived from the RS （radiosounding） measurements in the tropical oceanic upper troposphere. The measurements were performed four times per day during two intense observation periods （May 5-25, and June 5-25） on the Kexue #1 scientific observation ship of SCSMEX （South China Sea Monsoon EXperiment） in 1998. There are three new features obtained from our analysis. First, the responses of e and K to the onset of monsoon are negligible over the ocean at least for the data used here Second, the temporal variations of e and K are in a similar manner and exhibit strong diurnal variations. The diurnal variations achieve their maxima in the morning （08 LT） and early afternoon （14 LT）, and achieve their minima in the evening （20 LT） and early morning hours （02 LT）. The diurnal variations of turbulence parameters （e and K） and their responses to the onset of monsoon are entirely different from those derived over land at similar latitudes. Finally, although the correlations between the variations of e and MCSs （mesoscale convective systems）, which were derived from TRMM （tropical rainfall measuring mis- sion） satellite, are not very well in only few days, the diurnal variations of e averaged over May and June are strongly correlat- ed with the diurnal variations of MCSs with correlation factors of 0.79 and 0.94, respectively. This indicates that the turbulence and its diurnal variations over the tropic oceanic upper stratosphere region are highly related to the MCSs.

关键词： diurnal variation turbulence tropical troposphere mesoscale convection systems