Statistical properties of the temperature, relative humidity, and net solar radiation in the Blue Nile-eastern Sudan region

This paper presents the results of the first stage of an ongoing project of evaluating the spatial and temporal variability of soil water as fundamental factors for vegetation regeneration in the arid ecosystems in the Blue Nile-eastern Sudan. The specific aim of the present study is to understand the temporal and spatial variations of the major climate variables in the region and discuss its relevance to regional climate variability and changes. In this case, we systematically analyze the major climate variables (maximum and minimum air temperature, relative humidity, and net solar radiation). To evaluate the different characteristics of the climate variables, Mann–Kendall method, two-phase regression scheme, and wavelet transform technique are used; each method has its own strength and weakness, and the results of the three methods complement each other. The results show that the annual and seasonal maximum temperatures are increasing significantly. The annual minimum temperature and minimum temperature in dry seasons are decreasing. The minimum temperature in rainy season is increasing with a smaller rate as compared with the increase of maximum temperature in the season. The difference between maximum and minimum temperature is increasing in all the seasons. Net solar radiation in the region shows a significant increasing trend in all seasons, which corresponds well with the changes of maximum temperature. Besides, significant decreasing trends can be identified for relative humidity in all the seasons.     

南京地区夏季雷暴的雷达雷电特征分析

通过对2009年发生在南京的6次雷暴过程的雷达回波强度、VWP产品、垂直速度等雷达产品和探空资料等常规气象产品以及闪电资料的对比分析,发现VWP产品对雷暴过程中大气的湿度条件有较好的指示作用,ND区的初始破坏时间往往早于雷暴中闪电的发生时间。闪电主要发生在雷达最大回波顶高度突破9 km之后,并且最大回波顶高度较闪电峰值有约12 min的提前量。雷达平均垂直速度图中出现强上升中心后的短时间内闪电将会突然增大。     

准线形对流系统中强度—速度负相关性的特征研究

准线形对流系统(如飑线、弓形回波)是常见的强对流性系统,伴随它出现的一般是大风、旋风甚至冰雹等严重的灾害性天气现象.弓形回波有的是由一个单体产生的,也有嵌套在飑线或其他线形系统中,作为整个线形回波的一个部分.弓形回波能在很长的带上产生灾害性的直线风.在我们的研究中发现,准线形对流系统中,反射率因子(R)和径向速度(V)之间存在一定的负相关性,对发生在中国东部地区(24.5°-34.29°N,116.01°-119.52°E)的16个个例进行统计分析,发现在这些系统中都存在这种R-V负相关的特征,负相关的程度随高度有规律性的变化.通过对2006年6月29日个例的风场分析证实这种特征确实存在.对流系统与雷达射线方向接近垂直时,R-V负相关特征明显,这是因为该方向上,观测到的径向速度近乎等于实际风速,数值最大;而因垂直运动造成的水平风速减小并不因探测位置的不同而有很大变化.文中通过分析,推断R-V的这种负相关性与准线形系统中对流的强弱、中层径向辐合的强弱以及后向入流都有很大的关系.     

孟津县远程教育终端防雷装置安全性能的调查与思考

调查发现,孟津县远程教育终端防雷装置存在安全隐患:96%的终端卫星接收天线与避雷针的距离不合格;所有终端电源防护只有一级,电源也无穿管埋地敷设,有的电源没有经过sPD保护;所有卫星天线基座与避雷针基座只有一处连接,高频头均未采取屏蔽措施;所有机柜均未与等电位接地端子连接;所有终端天馈线与防雷引下线距离均＜1000 m.设计缺陷,施工人员素质低下,管理不到位.是造成上述问题的直接原因.气象部门应以此为诫,加强防雷管理,加强防雷执法,避免类似事件发生.     

Old stellar population synthesis： new age and mass estimates for Mayall Ⅱ = G1

Mayall Ⅱ = G1 is one of the most luminous globular clusters （GCs） in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKs 2MASS data, we construct the most extensive spectral energy distribution of G 1 to date, spanning the wavelength range from 1538 to 20 000A. A quantitative comparison with a variety of simple stellar population （SSP） models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ～1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates （of order 10^7M⊙） indicate that GI is one of the most massive GCs in the Local Group. However, we speculate that the cluster＇s exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, （1.65±0.63） × 10^2L⊙ far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.     

Atmospheric Refraction and Path Bending Delay

Owing to the effect of refraction on the propagation of electromagnetic waves in the terrestrial atmosphere, the direction of propagation is changed. The path of propagation path becomes a curve with an increased path-length so increasing the propagation time. A simplified spherically symmetric atmospheric model is adopted to calculate the delay caused by the path bending, for different zenith distances.     

Measuring global energy-related sulfur oxides emissions embodied in trade: a multi-regional and multi-sectoral analysis

Sulfur oxides (SO_X) emissions embodied in trade (SEET) may play an important role in affecting national responsibilities toward pollutant emission reduction within the context of global greenhouse gas emission policy. This paper analyzes the change of the SEET associated with energy consumption from the perspective of a country and a sector between 1995 and 2011, exploring the evolution characteristic of the sources and flows of the SEET for 39 countries, as well as measuring the production-based and consumption-based global SO_X emissions’ inventory and investigating the impact of international trade on the allocation of national pollutant emissions’ reduction obligations. One important finding is that the volume of SO_X emissions embodied in global trade increased dramatically from 1995 to 2011, and the global SO_X emissions stemming from anthropogenic energy consumption are mostly from China and the USA. Another important finding is that, referring to specific sectors, whether seen from the total SEET or from the sources of SEET or from the total SO_X emissions occurring from economic consumption and production, energy sectors, like electricity, gas, and water supply and coke, refined petroleum, and nuclear fuel, are the main contributors to the increase in the global SO_X emissions. Notably, however, our results show that the sector of agriculture, hunting, forestry, and fishing should be allocated more SO_X emission reduction responsibilities under a consumption-based emissions’ accounting inventory.