农田生态系统中重金属的积累积循环

本文通过对北京东郊高碑店地区污染农田的调查研究,探讨了重金属在农田生态系统中的积累和循环,计算出重金属在区域环境中的输入输出量,说明本区仍处于重金属积累状态,为防治农田环境污染,提出了停止施用污水处理厂的晾干污泥,减少灌溉污水中的重金属含量等保护性措施。     

XPer的新发射相：光谱与红外观测

ＸＰｅｒ的新发射相：光谱与红外观测杭恒荣，夏剑萍中国科学院紫金山天文台，南京２１０００８中国科学院光学天文联合实验室关键词Ｂｅ星／Ｘ射线双星，发射线，ＪＨＫ测光１引言ＸＰｅｒ是一颗Ｂｅ／Ｘ射线双星（４Ｕ０３５２＋３０）的光学对应体［１－３］，中子星的...     

多时相空间信息的动态可视化方法的研究及应用

目前如何处理地理信息随时间变化的动态特性成为GIS的重要研究方向之一。本文设计和实现了用于多时相空间信息几何特征、属性特征、属性专题统计特征的动态可视化的一些方法,建立了一套矢量动态符号库用于在地图上展示时空数据的几何和属性信息随时间变化的动态特性,实现了一组专题统计动态图表用于展示时空数据的属性专题统计结果随时间变化的动态特性。     

近50年来淮河流域极端降水的时空变化及统计特征(英文)

Based on the daily precipitation data of 27 meteorological stations from 1960 to 2009 in the Huaihe River Basin, spatio-temporal trend and statistical distribution of extreme precipitation events in this area are analyzed. Annual maximum series (AM) and peak over threshold series (POT) are selected to simulate the probability distribution of extreme precipitation. The results show that positive trend of annual maximum precipitation is detected at most of used stations, only a small number of stations are found to depict a negative trend during the past five decades, and none of the positive or negative trend is significant. The maximum precipitation event almost occurred in the flooding period during the 1960s and 1970s. By the L-moments method, the parameters of three extreme distributions, i.e., Generalized extreme value distribution (GEV), Generalized Pareto distribution (GP) and Gamma distribution are estimated. From the results of goodness of fit test and Kolmogorov-Smirnov (K-S) test, AM series can be better fitted by GEV model and POT series can be better fitted by GP model. By the comparison of the precipitation amounts under different return levels, it can be found that the values obtained from POT series are a little larger than the values from AM series, and they can better simulate the observed values in the Huaihe River Basin.     

中国北方典型沙尘天气特征研究

 根据API、风速、风向及相关气象数据初步研究了中国北方两次典型沙尘天气的天气特征。两次沙尘天气过程中极大风速大于7.2 m·s-1的气象站占88%。2005年4月27日极大风速超过17.2 m·s-1的气象站有31个,出现频率最高的风向为西西北,28日达到81个,风向为北风,极大风速高值区由内蒙古中东部向东北方向迅速扩大。2007年3月30日极大风速超过17.2 m·s-1的气象站有57个,31日达到68个,风向均为西西北,极大风速高值区分布较为稳定。受沙尘暴影响的地区API显著升高。2005年4月28日呼和浩特、大同、北京3个城市的API分别为418、500、500。2007年3月31日呼和浩特、赤峰、大同3个城市的API分别为500、500、423。对PM10与气象因子的相关性进行分析得出,沙尘暴期间,大气中可吸入颗粒物的浓度与风速存在显著的正相关关系,风速越高的地区,可吸入颗粒物的浓度越大。     

An Observational Analysis of a Derecho in South China

Derechos occur frequently in Europe and the United States, but reports of derechos in China are scarce. In this paper, radar, satellite, and surface observation data are used to analyze a derecho event in South China on 17 April 2011. A derecho-producing mesoscale convective system formed in an environment with medium convective available energy, strong vertical wind shear, and a dry layer in the middle troposphere, and progressed southward in tandem with a front and a surface wind convergence line. The windstorm can be divided into two stages according to differences in the characteristics of the radar echo and the causes of the gale. One stage was a supercell stage, in which the sinking rear inflow of a high-precipitation supercell with a bow-shaped radar echo induced a Fujita F0 class gale. The other stage was a non-supercell stage (the echo was sequentially kidney-shaped, foot-shaped, and an ordinary single cell), in which downbursts induced a gale in Fujita F1 class. This derecho event had many similarities with derechos observed in western countries. For example, the windstorm was perpendicular to the mean flow, the gale was located in the bulging portion of the bow echo, and the derecho moved southward along with the surface front. Some differences were observed as well. The synoptic-scale forcing was weak in the absence of an advancing high-amplitude midlevel trough and an accompanying strong surface cyclone; however, the vertical wind shear was very strong, a characteristic typical of derechos associated with strong synoptic-scale forcing. Extremely high values of convective available potential energy and downdraft convective available potential energy have previously been considered necessary to the formation of weak-forcing archetype and hybrid derechos; however, these values were much less than 2000 J during this derecho event.     

Subarea characteristics of the long-range correlations and the index χ for daily temperature records over China

Daily temperature records including daily minimum, maximum, and average temperature from 190 meteorological stations over China during 1951–2000 are analyzed from two perspectives: (a) long-term persistence in direction of time varies, and (b) standard deviation in direction of amplitude varies. By employing the detrended fluctuation analysis (DFA), we find all the temperature records are long-term correlated, while the exponent α obtained from DFA varies from different districts of China due to different climate conditions, such as the southwest monsoon, subtropical high, northeast cold vortex, and the Tibetan plateau, etc. After we take the standard deviation into account, a new index χ?=?α?×?σ, which has been proposed recently, can be obtained. By further rescaling it as $ \chi = \overline \chi - {{1} \left/ {5} \right.} \times {\sigma_{{\overline \chi }}} $ , we find an obvious change of χ for these three kinds of time series, from which the whole China can be divided into two groups, which are comparatively consistent with dry/wet distributions in the south–north areas over China.     

保定地区雷电分布特征及短时预警模型分析

根据保定市近2002—2011年18个地面观测站的雷暴日资料,分析研究了保定市雷电活动的时空分布特点。在此基础上利用保定市11部大气电场监测仪组网实时监测数据,找出电场幅值和上升率两个预警因子确定预警阈值,建立保定雷电短时预警模型。通过对36个雷电样本进行检验：提前30分钟预警的准确率达到60%,前20分钟达到74%,提前10分钟达到88%。结果表明,随着时间临近其预警准确率明显提高,对雷电短时预警具有很好的参考价值。     

内蒙古气象服务热线平台的设计与实现

内蒙古气象服务热线平台是基于Windows操作平台开发的一款应用于气象行业的C／S版声询信息管理系统。采用VOIP技术实现全国省（自治区）一级人工气象服务热线平台和中国气象局人工气象服务热线平台之间的联网,实现全国人工服务的联网。为达到中国气象局在全国范围内统一特服号码-4006000121,以省（自治区）为单位建设气象服务热线平台。     

新一代天气雷达故障处理和故障标准化平台的研发与应用

新一代天气雷达是一个组成结构复杂的探测平台,各个组合之间比较分散。由于机械运转的持续性,且对运行环境要求严格,所以雷达系统易发故障。对不同类型的雷达故障进行归纳和简析,并进行归类,按照雷达故障产生的原因分类为:雷达部件故障、软件故障、灾害引起的雷达故障、虚假报警、雷达产品图像错误。天气雷达故障处理和故障标准化平台的开发将相应的成果应用于日常的气象探测设备的监控业务中,并集成到综合气象观测系统运行监控平台,以实现天气雷达故障的快速响应和维修。对2007年6月至2010年5月新一代天气雷达的运行能力进行了计算,并抽样其中2种型号的天气雷达,对故障案例进行分析研究,给出了故障的分系统分布情况。