GPS短边网精度的研究

《ＧＰＳ测量规范》规定了ＧＰＳ测量的等级及各级ＧＰＳ网相邻点间距离,最低级Ｅ级网相邻点间距为１～１０ｋｍ,平均边长为２～５ｋｍ。根据工程的要求,有时控制网相邻点间距仅为几十至几百米,文中针对ＧＰＳ短边网的数据处理和精度进行分析,并对ＧＰＳ网的质量检核进探讨,采用全站仪对网进行检核发现ＧＰＳ边长误差在５ｍｍ以内。     

岩溶充填物突出机理与防治

随着岩溶矿山开拓面的不断延深和排水量的不断增大,地下水位将持续下降。由于受到地下水垂直渗流的冲刷作用,岩溶充填物不断向深部运移与沉积。当巷道揭露储泥溶洞时,岩溶充填物便迅猛喷泻突出,造成突泥事故。为能引起从事岩溶矿山生产建设人员的重视,作者探讨了岩溶充填物突出的必要条件、突出机理及防治突出事故的措施。      

THEMIS statistical study on the plasma properties of high-speed flows in Earth’s magnetotail

Using Time History of Events and Macroscale Interactions during Substorms(THEMIS) observations from 2007 to 2011 tail seasons, we study the plasma properties of high speed flows(HSFs) and background plasma sheet events(BPSs) in Earth's magnetotail(|Y_(GSM)|13R_E, |Z_(GSM)|5R_E, –30R_EX_(GSM)–6R_E), and their correlations with solar wind parameters. Statistical results show that the closer the HSFs and BPSs are to the Earth, the hotter they become, and the temperature increase of HSFs is larger than that of BPSs. The density and temperature ratios between HSFs and BPSs are also larger when events are closer to Earth. We also find that the best correlations between the HSFs(BPSs) density and the solar wind density occur when the solar wind density is averaged 2(3.5) hours prior to the onset of HSFs(BPSs). The normalized densities of both HSFs and BPSs are correlated with the interplanetary magnetic field(IMF) θ angles(θ=arctan(B_Z/((B_x~2)+(B_y~2))~(1/2) which are averaged 3 hours before the observation time. Further analysis indicates that both HSFs and BPSs become denser during the northward IMF period.     

Cassini growth of population between two metropolitan cities—A case study of Beijing-Tianjin region, China

The existing models of population distribution often focus on the region with a single city or even multiple centers, and lack the detailed explorations of the common and special type of urbanization areas with two centers. Taking Beijing-Tianjin region of China, which is a distinct dual-nuclei metropolitan area in the world, as an example and choosing Landsat-5 TM image in 2005, population, etc. as the data, this paper devotes to comprehending and illustrating a model of Cassini growth of population between the two metropolitan cities through the research of spatial population distribution pattern, aided with RS and GIS techniques. Main technical processes include Kriging interpolation of the population data and character simulation of the Cassini ovals. According to the calculation of a/b, a key characteristic index of Cassini growth model, the spatial structures of population distribution were given. When a/b<1, it is a curve with two separated loops with a population density more than 3000 persons/km². When a/b=1, it is a lemniscate curve with a population density about 3000 persons/km². When 1<a/b√2, it is a dog-bone shaped concave curve with a population density between 500–3000 persons/km². When a/b=√2, it is an oblate curve with a population density about 500 persons/km². When a/b>√2, there is an oval-shaped convex curve with a population density less than 500 persons/km². The results show that owing to the combined action and influence of the regional dual-nuclei, the population distribution of Beijing-Tianjin region is in accord with Cassini model significantly. There-fore, there is Cassini growth of population between the two metropolitan cities in Beijing-Tianjin region. In addition, the process of Cassini growth has extraordinarily instructive significance for judging the development stages of the dual-nuclei metropolitan areas. Foundation item: Under the auspices of National High-Tech Research and Development Program of China (863 Program) (No. 2007AA12Z235), National Natural Science Foundation of China (No. 40471058)     

13个水稻新不育系育性指标生态特性研究

以１９９７～１９９８年度参试的１３个新不育系为材料,依据在三亚市、武汉市和贵阳市三个地理生态区,进行分期播种试验所获得的套袋自交结实率和温度、日照长度资料,采用光温因子分极和育性量化模型等两种分析方法进行育性指标的生态特性研究,并初步分析了它们的生产实用价值。     

Re-examination of tropical cyclone formation in monsoon troughs over the western North Pacific

The monsoon trough(MT) is one of the large-scale patterns favorable for tropical cyclone(TC) formation over the western North Pacific(WNP). This study re-examines TC formation by treating the MT as a large-scale background for TC activity during May–October. Over an 11-year(2000–10) period, 8.3 TC formation events on average per year are identified to occur within MTs, accounting for 43.1% of the total TC formation events in the WNP basin. This percentage is much lower than those reported in previous studies. Further analysis indicates that TC formation events in monsoon gyres were included at least in some previous studies. The MT includes a monsoon confluence zone where westerlies meet easterlies and a monsoon shear line where the trade easterlies lie north of the monsoon westerlies. In this study, the large-scale flow pattern associated with TC formation in the MT is composited based on the reference point in the confluence zone where both the zonal and meridional wind components are zero with positive vorticity. While previous studies have found that many TCs form in the confluence zone, the composite analysis indicates that nearly all of the TCs formed in the shear region, since the shear region is associated with stronger low-level relative vorticity than the confluence zone. The prevailing easterly vertical shear of zonal wind and barotropic instability may also be conducive to TC formation in the shear region, through the development of synoptic-scale tropical disturbances in the MT that are necessary for TC formation.     

任意非规则边界填色等值线ActiveX控件及其在气象信息共享系统中的应用

气象信息服务图形化、网络化是当今拓宽气象服务领域和信息网络化发展的要求。利用条件距离倒数加权法实现了离散点数据网格化、规则格点跟踪实现了等值线绘制、Windows窗口裁剪技术实现了任意非规则边界填色等值线图形的绘制,并利用任意非规则边界填色等值线算法制作了功能完备的ActiveX控件,实现了Windows环境下的等值线图形信息互联网共享,为气象服务提供了一种技术支持手段,也为气象业务和科研提供了一种可选择的图形方法。     

2009年4月下旬蒙古气旋型大范围沙尘暴天气过程的诊断分析

本文利用卫星资料、加密实况观测资料、NCEP再分析资料分析了2009年4月下旬我国北方地区大范围沙尘天气过程的成因,并对热力、动力及不稳定层结等条件作了物理量诊断,得到了以下主要结论：贝加尔湖阻塞高压、高空冷涡及蒙古气旋是造成此次大范围沙尘天气的有利环流形势,其中蒙古气旋是关键影响系统;干暖舌位置对于沙尘落区有一定指示意义,沙尘暴落区与干暖舌的位置及移动方向一致;高空急流的发展演变与此次沙尘天气密切相关,沙尘天气主要发生在高空急流入口右侧,高空急流加强东移南压对应着沙尘天气东扩南压加强;螺旋度反映出沙尘暴过程中气旋区旋转上升明显,且螺旋度大值区后倾;理查逊数下降并维持低值、风垂直切变增大,大气层结不稳定,易激发沙尘暴发生和向下游传输。     

红海湾养殖水域营养盐消长与温度、盐度、浮游植物量的关系

红海湾海水养殖水域的营养盐、盐度、温度、浮游植物和叶绿素的观测结果表明,该水域中氨氮、亚硝酸盐及磷酸盐的消长受水系混合所制约。春季硝酸盐、氨氮和秋季磷酸盐与浮游植物之间存在着负相关,秋季表层叶绿素与营养盐（除氨外）存在着正相关,而底层叶绿素与营养盐存在密切负相关     

气候变化对椪柑病害发生的影响及防治

利用从江县1981~2005年5~10月逐日温度、降水、蒸发及持续降雨日数等气候资料,对气候变化诱发椪柑果树发生黄龙病病害进行研究。结果表明,5月下旬旬平均气温和6月上、中旬旬平均气温超过27℃、5月下旬至6月各旬降水蒸发差为正值以及持续降雨日数超过5天是椪柑夏梢发生黄龙病病害的主要因子,5月上、中旬旬平均温度、旬降水蒸发差对黄龙病病害发生的影响不明显。春末夏初高温高湿是椪柑果树夏梢发生黄龙病病害的重要条件。