浙西南热带气旋强降水主要影响因子

对1950-2010年影响浙西南的热带气旋降水的移动路径、影响时间、强度、西风槽、西南季风以及地形等主要因子进行分析.结果表明:在玉环南-厦门一带登陆的热带气旋是影响浙西南的热带气旋中正面影响浙西南的类型,影响时间和最大平均过程降雨量、最大过程雨量存在着正相关关系,热带气旋的强度与其降水强度相关性较高.西风槽的存在不仅影响着热带气旋路径的变化,其槽前的西南气流也为热带气旋降水提供充足的水汽,同时槽后冷空气与热带气旋相结合,使丽水的西北部出现另一个强降水中心.西南季风为登陆后的热带气旋提供了水汽条件,使降水得到增幅.浙西南独特的地形,使在厦门以北到玉环以南登陆后西进、西北行或西北行后在120°E以西转向北上的热带气旋迎着山脉进入,降水强度明显加强.     

地面气象测报业务试题库自动化管理系统

将地面气象观测规范、地面气象观测、气象学等多项知识形成题库,利用VB6编程、Access 2003数据库及Word 2003文字处理软件,研制了地面气象测报业务试题库自动化管理系统,实现了以下主要功能:用户管理、数据库管理、试题库维护、自动生成试卷、试卷编辑打印。着重阐述该系统的设计思路、技术方法、功能实现及使用效果。     

用于风电场功率预测的逐时风速预报

为满足风电场精细化风速预报的需要,利用MM5模式的格点输出数值预报产品以及福建沿海地区两座海上测风塔的逐时气象资料,采用逐步回归的统计方法,将MM5数值预报产品与测风塔实测气象资料要素指标值共同引入回归方程,拟合两座测风塔特定高度的逐小时风速预报方程,详细介绍了该方法的实现过程.通过一年的预报效果指标以及15日的独立样本效果检验,结果表明该方法对于逐小时风速的预报有一定的应用价值.     

Artificial Martian frozen orbits and Sun-Synchronous orbits using continuous low-thrust control

This paper analyses three types of artificial orbits around Mars pushed by continuous low-thrust control: artificial frozen orbits, artificial Sun-Synchronous orbits and artificial Sun-Synchronous frozen orbits. These artificial orbits have similar characteristics to natural frozen orbits and Sun-Synchronous orbits, and their orbital parameters can be selected arbitrarily by using continuous low-thrust control. One control strategy to achieve the artificial frozen orbit is using both the transverse and radial continuous low-thrust control, and another to achieve the artificial Sun-Synchronous orbit is using the normal continuous low-thrust control. These continuous low-thrust control strategies consider J ₂, J ₃, and J ₄ perturbations of Mars. It is proved that both control strategies can minimize characteristic velocity. Relevant formulas are derived, and numerical results are presented. Given the same initial orbital parameters, the control acceleration and characteristic velocity taking into account J ₂, J ₃, and J ₄ perturbations are similar to those taking into account J ₂ perturbations for both Mars and the Earth. The control thrust of the orbit around Mars is smaller than that around the Earth. The magnitude of the control acceleration of ASFOM-4 (named as Artificial Sun-Synchronous Frozen Orbit Method 4) is the lowest among these strategies and the characteristic velocity within one orbital period is only 0.5219 m/s for the artificial Sun-Synchronous frozen orbit around Mars. It is evident that the relationship among the control thrusts and the primary orbital parameters of Martian artificial orbits is always similar to that of the Earth. Simulation shows that the control scheme extends the orbital parameters’ selection range of three types of orbits around Mars, compared with the natural frozen orbit and Sun-Synchronous orbit.     

Analysis of the potential field and equilibrium points of irregular-shaped minor celestial bodies

The equilibrium points of the gravitational potential field of minor celestial bodies, including asteroids, comets, and irregular satellites of planets, are studied. In order to understand better the orbital dynamics of massless particles moving near celestial minor bodies and their internal structure, both internal and external equilibrium points of the potential field of the body are analyzed. In this paper, the location and stability of the equilibrium points of 23 minor celestial bodies are presented. In addition, the contour plots of the gravitational effective potential of these minor bodies are used to point out the differences between them. Furthermore, stability and topological classifications of equilibrium points are discussed, which clearly illustrate the topological structure near the equilibrium points and help to have an insight into the orbital dynamics around the irregular-shaped minor celestial bodies. The results obtained here show that there is at least one equilibrium point in the potential field of a minor celestial body, and the number of equilibrium points could be one, five, seven, and nine, which are all odd integers. It is found that for some irregular-shaped celestial bodies, there are more than four equilibrium points outside the bodies while for some others there are no external equilibrium points. If a celestial body has one equilibrium point inside the body, this one is more likely linearly stable.     

电离层延时对低轨卫星频率传递的影响分析

利用低轨卫星,对受干扰区域的卫星导航接收机进行频率传递,是提升其性能的一种有效手段.而电离层延时误差是影响传递效果的重要因素.对基于低轨卫星的频率传递应用背景进行了介绍,分析了其基本原理,并着重分析了电离层延时的存在对频率传递的影响,提出利用站间差历元差的方法对电离层延时进行修正.最后,通过仿真对理论分析进行了验证.结果表明,通过站间差历元差的手段,对当前电离层变化值进行求解与预测,可以将电离层延时误差的变化控制在一定范围,满足频率传递的要求.     

Low-dimensional chaos and fractal properties of long-term sunspot activity

Two primary solar-activity indicators sunspot numbers(SNs)and sunspot areas(SAs)in the time interval from November 1874 to December 2012 are used to determine the chaotic and fractal properties of solar activity.The results show that(1)the long-term solar activity is governed by a low-dimensional chaotic strange attractor,and its fractal motion shows a long-term persistence on large scales;(2)both the fractal dimension and maximal Lyapunov exponent of SAs are larger than those of SNs,implying that the dynamical system of SAs is more chaotic and complex than SNs;(3)the predictions of solar activity should only be done for short-to mid-term behaviors due to its intrinsic complexity;moreover,the predictability time of SAs is obviously smaller than that of SNs and previous results.     

西天山海西中期花岗岩的地质特征及其构造环境

海西中期花岗岩是西天山加里东褶皱带内规模最大的一次岩浆活动。本文从岩石学、矿物学、岩石化学和地球化学等方面对该期花岗岩的成因类型、岩浆起源和形成的构造环境进行了探讨，认为海西中期花岗岩以Ｉ型为主，Ｓ型次之，在空间上成对分布，花岗岩浆起源于地壳；海西中期花岗岩形成于活动大陆边缘岛孤环境．     

ANALYSIS ON AGRICULTRUAL INFORMATION DEMAND——Case of Jilin Province

With the rapid development of agricultural informalization in the world, the demand of agricultural information has been a focus in the international agriculture and information fields. Based on the investigation, this paper presented the four characteristics of the demand of agricultural information in China, includingregionality, seasonality, great potential demand and variation in kind and level. The factors infuencing the demand of agricultural information were analyzed by the Optimized Less Square （OLS） method. The result shows that, of all factors influcing agricultural information demand, the most important one is economy, the second is facility of information pass, and knowledge and education of user, credit of agricultural information service system and production situation follow. Taking Jilin Province as an example, this article also elaborated the agricultural information demand status, and deduced the regression model of agricultural information demand and verified it by the survey in rural Jilin.     

CIRCULAR-ECONOMY MODELS OF ANIMAL HUSBANDRY INDUSTRY IN JILIN PROVINCE

1INTRODUCTION The circular-economyisan efficient resources metabolic process, based on principles of ecology and system engi- neering.Withcoupledstructure andthe complex ecolo- gical and economic evolution, it has the characteristics of overall integrity, coordination, and circulation (WANG, 2005). Compared with the traditionalecono- mic model, the circular-economy requires the technical model of production process to be changed from the opening flow pattern that is "resourcesconsumption…