Observation of Small-amplitude Electromagnetic Cyclotron Waves in the Solar Wind

Our previous studies on low-frequency electromagnetic cyclotron waves(ECWs) with amplitudes larger than 0.1nT in the solar wind revealed that the left-handed(LH) polarized ECWs are the dominant waves,and these waves preferentially occur in plasma conditions of high proton speed(V_p),high proton temperature(T_p),low proton density(N_p).In the present study,using magnetic field and plasma data from the Wind mission between 2005 and2015,we perform a survey of small-amp...     

Influence of Solar Activity on Precise Orbit Prediction of LEO Satellites

The perturbations of low earth orbit(LEO) satellites operating in the orbit of 300～2000 km are complicated.In particular,the atmospheric drag force and solar radiation pressure force change rapidly over a short period of time due to solar activities.Using spaceborne global positioning system(GPS) data of the CHAMP,GRACE and SWARM satellites from 2002 to 2020,this paper studies in depth the influence of solar activity on LEO satellites’ precise orbit prediction by performing a series of orbit pre...     

Design,Fabrication and Assembly of the Solar Upper Transition Region Imager(SUTRI)

The Solar Upper Transition Region Imager(SUTRI) focuses on the solar transition region to achieve dynamic imaging observation of the upper transition region. In this paper, we report the optical system design, mechanical design, ultrasmooth mirror manufacture and measurement, EUV multilayer film coating, prelaunch installation and calibration for the SUTRI payload at IPOE, Tongji University. Finally, the SUTRI carried by the SATech-01satellite was successfully set to launch. All functions of thi...     

Statistical Properties of Alfvén Ion Cyclotron Waves and Kinetic Alfvén Waves in the Inner Heliosphere

Alfvén ion cyclotron waves(ACWs) and kinetic Alfvén waves(KAWs) are found to exist at <0.3 au observed by Parker Solar Probe in Alfvénic slow solar winds. To examine the statistical properties of the background parameters for ACWs and KAWs and related wave disturbances, both wave events observed by Parker Solar Probe are selected and analyzed. The results show that there are obvious differences in the background and disturbance parameters between ACWs and KAWs. ACW events have a relatively hi...     

钱塘江河口风暴潮经验预报

钱塘江河口的风暴潮预报工作可归结为澉浦或乍浦两个单站的预报,这使得经验预报成为可能。利用一种动力线性模型将动力学的线性问题转化为统计学的线性回归模型,通过合理选取预报量及预报因子,并采用正交筛选技术确定每个预报因子所对应的系数,建立经验预报方程。后报结果表明该方法可取得较好的效果。     

马氏珠母贝生长性状的相关分析

对马氏珠母贝(Pinctadamartensi)不同生长时期的壳长、壳高、壳宽和活体质量进行了一年多的跟踪测量。分析表明,在不同生长时期,其4个性状的两两间的相关系数均达到极显著水平(P<0.01),但其相关系数大小排列顺序存在差异,8次测量的平均相关系数大小依次为壳高-壳长>壳宽-体质量>壳高-体质量>壳长-体质量>壳长-壳宽>壳高-壳宽。在不同生长时期,活体质量对壳高、壳宽的偏回归系数均极显著(P<0.01),而对壳长的偏回归系数在第1,3,7,15个月时不显著(P>0.05)。该研究的结果可为珍珠贝的选育种的重要目标性状的确定提供理论指导。     

Comparative study of different machine learning models in landslide susceptibility assessment:A case study of Conghua District,Guangzhou,China

Machine learning is currently one of the research hotspots in the field of landslide prediction. To clarify and evaluate the differences in characteristics and prediction effects of different machine learning models,Conghua District, which is the most prone to landslide disasters in Guangzhou, was selected for landslide susceptibility evaluation. The evaluation factors were selected by using correlation analysis and variance expansion factor method. Applying four machine learning methods namely ...     

基于夜间灯光数据的环渤海地区城市化空间模式和过程研究

1 Introduction Urban agglomeration is a system of cities, supporting by the modern transportation and information network in the system, these cities, with different characteristics, types, sizes and hierarchies, interact with each other, and one or two …     

藏北高原地壳及上地幔导电性结构——超宽频带大地电磁测深研究结果

为了研究西藏中、北部壳、幔导电性结构,讨论高原中、北部岩石圈热状态,1998年和1999年（INDEPTH（Ⅲ） MT）在西藏中、北部完成了德庆—龙尾错（500线）和那曲—格尔木（600线）超宽频带大地电磁深探测剖面的研究.研究结果表明,西藏中、北部以昆仑山断裂为界,其南北壳、幔电性结构有很大差异.昆仑山断裂以北地壳和上地幔为高阻区.而昆仑山以南,地壳和上地幔的导电性有明显的分层结构：地壳上部以不连续的高阻体为主,夹有局部低阻异常体,沿南北方向上地壳的电性结构复杂,具有不连续、分块的特点;但中、下地壳为大范围的高导异常区,区内发育有大规模、不相连续、产状各异的高导体,其电阻率均小于4Ωm;在班公—怒江和金沙江缝合带之下,壳内高导体都具有向上地幔延伸的趋势,存在连通壳、幔的低阻通道.根据西藏高原中、北部壳、幔电性结构的研究推断：如同藏南一样,这里也普遍存在部分熔融体和热流体,它们的成因主要与班公—怒江和金沙江缝合带的壳-幔热交换、热活动有关,这是两期形成的壳-幔热交换通道.其中,班公—怒江缝合带的壳-幔热交换通道形成时间比金沙江缝合带早.因此,研究区壳、幔的热活动是从南边和西边开始,向北、向东扩展,导致现今西藏中、北部地壳和上地幔的热流分布由西向东、由南向北增大.     

Computation of the atmosphere-less light intensity curve during a total solar eclipse by using Lunar Reconnaissance Orbiter topography data and the DE430 astronomical ephemeris

Observations of the sky irradiation intensity in the visible wavelengths during a solar eclipse permit to model the Sun diameter,a key number to constrain the internal structure of our star.In this paper,we present an algorithm that takes advantage of the precise Moon topography from Lunar Reconnaissance Orbiter to compute,with a high resolution in time,the geometrical part(i.e.top-of-atmosphere,and for a given wavelength)of the sky irradiation at any given location on the Earth during these events.The algorithm is also able to model the Baily’s beads.We give as an application the theoretical computation of the light curve corresponding to the solar eclipse observed at Lakeland(Queensland,North Australia)on 2012 November 13.The application to real data,with the introduction of atmospheric and instrumental passbands,will be considered in a forthcoming paper.