中国地震预警延迟时间算法及其对预警盲区的影响研究

通过分析预警系统的预警步骤来探讨影响获得预警时间的因素,并与瑞士地震台网预警延迟各步骤进行对比,得出中国地震预警系统仪器延迟时间为7.6s。提出地震波到台站所需时间的算法,较震中假设在台站中间的传统算法更为准确,在此算法下采用双台法和四台法计算接收地震波所需时间,得到中国地震预警延迟时间。讨论双台法和四台法在不同震源深度和台站密度下对预警盲区大小的影响,在台间距小于20km时,2种方法预警盲区差异不大。通过理论计算得出,在台站到达一定密度时,预警系统仪器延迟时间缩短比台站加密对预警盲区的缩小更有效。     

Spectral Characteristics of Solar Flares in Different Chromospheric Lines and Their Implications

Using the spectral data of representative solar flares observed with the infrared detector system of the solar spectrograph at Purple Mountain Observatory, we study the spectroscopic characteristics of solar flares in the Hα, the Ca i i 8?542 Å, and the He i 10?830 Å lines in different phases and various locations of flares and discuss their possible implications coupled with space observations. Our results show that in the initial phase of a flare the Hα line displays a red shift only with no wide wing. Large broadenings of the Hα line are observed a few minutes after the flare onset within small regions of 3?–?5^′′ in both disk and limb flares with and without nonthermal processes. Far wings similar to those of damping broadening appear not only in the Hα line but in the He i 10?830 Å line as well in flares with nonthermal processes. Sometimes we even detect weak far-wing emission in the Ca i i 8?542 Å line in disk flares. Such large broadenings are observed in both the footpoints and the flare loop-top regions and possibly result from strong turbulence and/or macroscopic motions. Therefore, the so-called nonthermal wing of the Hα line profile is not a sufficient condition to distinguish whether nonthermal electrons are accelerated or not in a flare. The Ca i i 8?542 Å line shows lower intensity in the loop-top regions and higher intensity in the parts close to the solar surface. Emissions larger than nearby continuum in the He i 10?830 Å line are detected only in small regions with strong X-ray emissions and avoid sunspot umbrae.     

Evaluation of CMP AS precipitation products over Sichuan,China

高质量和高分辨率的降水产品在天气预报,数值模式模拟和气象防灾减灾方面起着重要的作用.本文利用四川地区高密度的地面降水传感器观测数据,比较CMPAS四种不同时空尺度的降水实况分析产品,评估CMPAS的融合准确性与在四川地区的适用性.研究表明:四种CMPAS降水产品都在四川盆地内精度较高,攀西地区和川西高原次之.随着降水量...     

基于Direct3D的光照机制研究

为增强三维场景的真实感,可通过为场景增加光照来实现。文中在光照应用理论的基础上,通过对Direct3D中光照机制的研究,探讨光照机制对光照效果产生的影响。通过实验提出平坦地面特殊灯光效果应用问题的解决方案,并就方案的运行效果和效率进行分析研究,对Direct3D的开发应用尤其是特殊灯光效果的应用具有一定的参考价值。     

Environmental ethics and regional sustainable development

The scientific environmental ethics plays a key role in the recognition of the human- environment interactions. Modern environmental ethics is the philosophical re-thinking of modern human race environmental behavior. The development of environmental ethics theory, as well as its application in reality, determines the viewpoints of environmental ethics. Sustainable development implies harmony on human-environment interactions and inter- generation responsibility, with emphasis on a harmonious relationship among population, resources, environment and development, so as to lay a sustainable and healthy foundation of resources and environment for future generations. The harmonious society construction in China that is raised by the Chinese central government should be covered by environmental ethics. The connotation of open environmental ethics includes a respect for nature, care for the individual human race, and respect for the development of future generations, which means giving consideration to natural values, individual and human race benefits and welfare across generations. The role of environmental ethics in regional development consists of cognition, criticism, education, inspiration, adjusting, legislation and promoting environmental regulations. The major problems in regional development are extensive resource exploration, fast population growth, irrational industrial structure, unfair welfare distribution and the twofold effects of science and technology development. The formulation of environmental ethics that aims at regional sustainable development, can not only harmonize the relationship of population, resource, environment and economic development, but also guide behavior selection, push social and political system transformation, strengthen the legal system, and raise environmental awareness of the public.     

长三角区域知识合作网络演化的空间特征

借助社会网络方法和动态演化的视角,对1991—2010年长三角16个地区间知识合作网络演化的空间特征进行考察,剖析了各时段内网络空间分布特征及空间格局、网络节点的空间驱动机制和区域知识合作的空间选择倾向。结果表明:长三角区域知识合作网络演化过程存在空间极化现象,以沪宁为轴线的苏南地区明显优于浙北地区;区域结网的空间驱动方式逐步由沪宁杭为主的大城市驱动向中小城市驱动转变;知识合作网络在空间上呈明显的核心-边缘格局并将长期存在。地理临近、行政区临近和知识规模临近是影响区际知识合作空间对象选择的主要因素。其中,知识规模临近的作用不断增强,而地理临近与行政区临近的作用则不断减弱。     

掩星接收机误差对大气温度反演精度影响仿真研究

为了评估掩星接收机误差对无线电掩星探测精度的影响,利用EGOPS软件仿真研究了多普勒偏差、多普勒频移、时钟稳定性/单差分、接收机噪声和局部多路径等对GNSS无线电掩星反演大气温度、折射率、密度、压力廓线的影响.模拟设计过程中选择METOP作为接收的LEO卫星,GPS星座作为发射系统,设置GRAS天线.从模拟的567个掩星事件中选择了一个上升掩星事件和一个下降掩星事件进行模拟分析.研究结果表明:对于设置的"最差"情况,温度误差最大值大部分出现在平流层顶附近,其中多普勒偏差引起的温度误差最大值接近2 K,多普勒频移引起的温度误差最大值小于0.3 K,时钟稳定性/单差分引起的温度误差最大值接近3 K,现实接收机噪声引起的温度误差最大值超过了4 K,局部多路径引起的温度误差最大值小于1.5 K.经讨论分析认为:对于高质量的无线电掩星反演,掩星接收机误差源中最主要的是接收机热噪声、时钟稳定性/单差分和多普勒偏差.文中还随机选取了30个掩星事件进行统计分析,将其温度反演结果与ECMWF分析场数据比较得出,温度误差的平均偏差在45 km高度上最大,约为1 K;最大标准偏差出现在平流层顶,约为5 K,这验证了廓线反演算法的有效性,表明了误差分析结果的正确性和普遍性.     

2008年初低温、雨雪、冰冻灾害的成因分析

本文对郴州市2008年1月中旬至2月上旬出现的历史罕见雨雪冰冻天气灾害的特点,天气、气候成因和地形作用等方面进行了深入细致剖析.结果表明:中低层的逆温和强盛的西南暖湿气流、冷暖空气在长江中下游地区稳定对峙是产生重度冰雪天气的必要条件,郴州特殊地形增加了冰冻强度和持续时间.这些分析结论对今后开展冰雪天气预报预警业务和科研工作都有重要参考作用.