预报文稿解译与精细化发报程序相结合的应用

采用在原有的预报流程基础上,通过解译预报文稿与精细化发报程序结合应用来制作预报。在实际应用中能够正确快速的把预报文稿进行翻译并入库,缩短了制作预报的时间,提高了预报业务流程的完整性,减轻了预报员的劳动量,同时也避免了重复性工作,为及时准确的发报工作提供了保证。     

地下水综合指数评价法——起始污染指数及其应用

本文在分析了现有的综合指数评价公式之后,提出了一种新的评价公式——起始污染指数,该公式易于识别地下水轻微的污染,能较真实地反映出地下水污染状况,对地下水的防护与治理起到了积极的作用。最后以泰安市的污染状况为例,进行了不同评价公式的应用对比。     

基于瓦片数据结构的大规模地形构建与显示

地形漫游在仿真、模拟、虚拟现实、游戏等领域都有广泛的应用，但其大规模地形实时动态绘制的速度和质量一直是一个难点。文章主要分析了地形场景数据管理与实时调度、视相关多层次细节模型与可见性判断以及分层数据组织与瓦片数据绘制等关键问题。在研究多种层次算法的基础上，提出了一种实时高帧率绘制大规模地形的瓦片重组数据结构的方法，并改进了视景体裁切重组地形数据的方法。实验结果表明该方法在保持地形逼真的情况下，有很好的绘制网格帧率和实时动态交互的效果。     

Accuracy Analysis of Geopotential Coefficients Recovered from In-situ Disturbing Potential by Energy Conservation Method

The characteristics of the normal equation created in recovering the Earth gravity model (EGM) by least-squares(LS) adjustment from the in-situ disturbing potential is discussed in detail. It can be co...     

Comparison between earthquake magnitudes determined by China seismograph network and US seismograph networks (I): Body wave magnitude

Introduction Gutenberg (1945a, b) introduced body wave magnitude based on P, PP and S waves (with a period of 0.5~12.0 s) of teleseismic events. Body wave magnitude includes mb determined with short-period seismograph and mB determined with middle- and long-period seismographs. Some-times it is written as m, which is referred to as unified earthquake magnitude. mb represents earth-quake magnitude measured with body wave amplitude around 1 s, while mB represents earthquake magnitude measured …     

地震观测中的防雷技术

作者在地震观测台站建设的实践基础上,提供一套完整而易于操作的防雷设计和运行解决方法来保护地震观测系统,使通信线路、设备正常运行。     

河南省小麦青枯发生规律的EOF分析

通过对河南省30个台站1967~1996年30年的气象资料统计,得出全省小麦青枯发生日数,对其进行EOF分析,发现全省小麦青枯发生日数主要呈“中部多南北部少”空间分布型,另外还有其它几种空间分布型;小麦青枯发生日数随时间推移呈减少趋势;对各模态时间系数进行功率谱分析,发现小麦青枯发生日数具有较明显的准3年周期;第一、第二模态时间系数与全省小麦单产存在显著负相关关系,为防御和减轻小麦青枯灾害提供了理论依据。     

华南南部旱情持续中东部地区大雾多

11月份 ,全国大部地区降水量比常年同期偏多 ,长江中下游和华南北部出现明显降水 ,旱情缓解 ,但华南中部和南部干旱仍持续或发展 ;月平均气温 ,全国大部地区较常年同期偏高或接近常年 ,其中东北部分地区偏高显著 ,黑龙江、吉林两省月区域平均气温为1 951年以来历史同期最高值 ;月日照时数 ,全国大部地区接近常年同期。总的来看 ,本月全国大部地区光热水条件适宜 ,天气气候对农业生产比较有利。月内 ,浙江、四川、重庆、新疆等地局地发生暴雨、洪涝或泥石流、滑坡灾害 ;中东部地区出现大雾天气 ,部分地区因雾引发多起交通事故 ,造成人员伤亡 …     

Annual and semiannual variations in the ionospheric F2-layer. I. Modelling

Annual, seasonal and semiannual variations of F2-layer electron density (NmF2) and height (hmF2) have been compared with the coupled thermosphere-ionosphere-plasmasphere computational model (CTIP), for geomagnetically quiet conditions. Compared with results from ionosonde data from midlatitudes, CTIP reproduces quite well many observed features of NmF2, such as the dominant winter maxima at high midlatitudes in longitude sectors near the magnetic poles, the equinox maxima in sectors remote from the magnetic poles and at lower latitudes generally, and the form of the month-to-month variations at latitudes between about 60°N and 50°S. CTIP also reproduces the seasonal behaviour of NmF2 at midnight and the summer-winter changes of hmF2. Some features of the F2-layer, not reproduced by the present version of CTIP, are attributed to processes not included in the modelling. Examples are the increased prevalence of the winter maxima of noon NmF2 at higher solar activity, which may be a consequence of the increase of F2-layer loss rate in summer by vibrationally excited molecular nitrogen, and the semiannual variation in hmF2, which may be due to tidal effects. An unexpected feature of the computed distributions of NmF2 is an east-west hemisphere difference, which seems to be linked to the geomagnetic field configuration. Physical discussion is reserved to the companion paper by Rishbeth et al.