晴空与有云大气辐射分布的数值模拟及其对全天空图像云识别的应用

全天空图像自动云识别的研究相对来说是一项较新的研究领域。当前国际上较为通用的全天空图像云识别方法主要依靠图像蓝红灰度值对比的阈值方法进行判断。然而非洁净大气中气溶胶的增多给云识别增加了难度,同时太阳高度角不同天空色度分布情况也不同。文中利用Libradtran辐射传输模式,计算了不同能见度不同太阳高度角情况下3个典型波长(450,550,650nm;蓝/绿/红)无云及有云大气的天空辐亮度分布情况,并进行了比较分析。结果表明,相同太阳高度角情况下,无云及有云大气中蓝红比值随能见度的下降呈单调下降趋势。在特定的云光学厚度和能见度情况下,天空色度彼此呈现出类似的分布状况。全天空图像阈值判断云识别自适应算法的建立需要与太阳高度角、地面能见度联系起来。当前尚无法建立一个判断阈值随太阳高度角以及能见度变化的函数关系式。较为可行的办法是建立典型能见度、典型太阳高度角情况下的辐射信息库,在具体云识别时,首先确定太阳高度角,而后根据天空辐射比情况确定天空能见度,并利用辐射信息标准库做云或非云判别。该工作为全天空云识别算法提供判别依据,同时建立云识别随能见度和太阳高度角变化的判别信息库。     

电视气象节目的市场化运营

在当今以受众者为核心的传播时代,电视气象节目的发展应与电视传媒的整体变革同步进行;逐步完善节目的内容和形式,逐步达到受众的欣赏要求,逐步实现节目的市场化运营.     

Evaluating Local Non-Stationarity when Considering the Spatial Variation of Large-scale Autocorrelation

Multi‐scale effects of spatial autocorrelation may be present in datasets. Given the importance of detecting local non‐stationarity in many theoretical as well as applied studies, it is necessary to “remove” the impact of large‐scale autocorrelation before common techniques for local pattern analysis are applied. It is proposed in this paper to employ the regionalized range to define spatially varying sub‐regions within which the impact of large‐scale autocorrelation is minimized and the local patterns can be investigated. A case study is conducted on crime data to detect crime hot spots and cold spots in San Antonio, Texas. The results confirm the necessity of treating the non‐stationarity of large‐scale spatial autocorrelation prior to any action aiming at detecting local autocorrelation.     

土-结构动力相互作用研究综述

土与结构动力相互作用是当代力学领域的前沿性研究课题,具有很强的实践性。对土与结构动力相互作用的研究历史与现状进行了介绍,简要综述了当前土与结构动力相互作用的研究方法,重点介绍了目前关于土与结构动力相互作用问题中从无限域转化成有限域的人工边界研究进展问题,并对该领域今后的研究工作提出了建议。     

"地震数值模拟的数据库应用平台"项目成果介绍

利用计算机模拟复杂的系统和过程,是当今世界科技发展的新潮流,在地学领域,数值模拟已经渗透到地学研究的各个重大领域。本项目提出建立一个用于地震模拟和预报的数据库应用平台,以地壳动力学研究和强震机理研究为应用核心,将地震地质研究、地形变研究、地应力研究、地球内部结构研究等多种相关的学科手段的观测资料、实验结果和理论分析有机地结合起来,实现技术和数据资源的共享。利用这些信息构建比较合理的地球模型和尽可能多的约束条件,并在有限元分析系统上进行地壳形变和地震过程的数值模拟。     

Integration of transfer function model and back propagation neural network for forecasting storm sewer flow in Taipei metropolis

Typhoons and storms have often brought heavy rainfalls and induced floods that have frequently caused severe damage and loss of life in Taiwan. Our ability to predict sewer discharge and forecast floods in advance during storm seasons plays an important role in flood warning and flood hazard mitigation. In this paper, we develop an integrated model (TFMBPN) for forecasting sewer discharge that combines two traditional models: a transfer function model and a back propagation neural network. We evaluated the integrated model and the two traditional models by applying them to a sewer system of Taipei metropolis during three past typhoon events (NARI, SINLAKU, and NAKR). The performances of the models were evaluated by using predictions of a total of 6 h of sewer flow stages, and six different evaluation indices of the predictions. Finally, an overall performance index was determined to assess the overall performance of each model. Based on these evaluation indices, our analysis shows that TFMBNP yields accurate results that surpass the two traditional models. Thus, TFMBNP appears to be a promising tool for flood forecasting for the Taipei metropolis sewer system. For publication in Stochastic Environmental Research and Risk Analysis.     

Variations of near-surface atmospheric CO2 and H2O concentrations during summer on Muztagata

Expeditions during the summers of 2002 and 2003 implemented continuous monitoring of near-surface (2 m height) atmospheric CO₂ and H₂O concentrations at the 4500 m elevation on Muztagata. The resultant data sets reveal a slight decrease of CO₂ concentrations (of about 5 μmol·mol^-1) and changes in the diurnal variations from the end of June to the middle August. The daily maximum CO₂ concentrations occur between 02:30-05:30 AM (local time) and the minimum levels occur between 12:00-15:30 PM. The atmospheric CO₂ concentrations in the summer of 2002 were around 5 μmol·mol^-1 lower than those during the same period of 2003, whereas the diurnal amplitude was higher. In contrast, we found that the daily mean atmospheric H₂O content in 2003 was much lower than that in 2002 and there exists a striking negative correlation between CO₂ and H₂O concentrations. We therefore suggest that the near-surface atmospheric CO₂ concentration is affected not only by photosynthesis and respiration, but also by the air H₂O content in the glaciated region around Muztagata.     

日本2006年度地震调查研究项目简介

日本地震调查研究推进本部于2005年8月30日召开第22次本部会议,汇总文部科学省、经济产业省、国土交通省等有关部门的2006年度地震调查研究预算,概算要求总额达131亿日元(不包括独立行政法人等运作经费),比2005年度预算额增加41%。在此之前,地震调查研究本部政策委员会的预算小     

四川省森林火险预报系统

四川省森林火险预报系统是用VB6.0语言编写,采用多因子线性回归统计方法建立的一套森林火险等级预报业务系统;本系统通用性强、功能齐全,为预报员提供了一套较完备的火险等级预报工具,同时实现了等值线这一科学计算可视化表现方式,摆脱了对专业绘图软件的依赖.     

L波段碳湿敏元件特性试验

目前国内大部分探空站已经启用新一代探空仪——上海长望气象科技有限公司生产的L波段电子探空仪。新探空仪的数据率、测量准确度和可靠性都有较大的提高。新探空仪使用的湿度敏感元件是碳湿敏电阻。我们利用工厂添置的能测到-30℃低温的高精度湿度校准设备，进行了大量静态测试，进一步验证了碳湿敏元件与老探空仪使用的肠衣敏感元件相比，灵敏度高，滞后小，在高空低温期间感应陕，测量准确度有较大提高。