Entropy inference of recurrence models for variability analysis of extreme events

A complete methodology is developed to analyze the recurrence of extreme environmental events and its variability as time without further events elapses. Firstly we investigate the conditioned recurrence inference problem consisting in the selection of a probability model for the interarrival time between extreme events, given a contexto-factual evidence conditioned by the time elapsed since the last of such events. Two ways to include this condition can be considered, which yield alternative conditioned evidences and convert the former problem into two distinct ones, thus giving rise to a possible consistency violation. These problems are formalized within the logical probability framework, in a plausible logic language that allows a suitable expression of the available observational data. They are solved using the REF relative entropy method with fractile constraints, and their solutions are compared at all inference levels. It is concluded that the two conditioning ways are not really mutually exclusive and that a unique global solution to the conditioned inference can be obtained using this procedure. An example illustrates an application of the methodology to the variability analysis of the recurrence time between historical inundations of the Guadalquivir river in Spain, as time elapses with no new floods.Acknowledgments. Support for this work was provided by DGI of Spain as the grant REN2000-2988-E/CLI and the research project REN2002-01337/CLI.     

北京奥运期间极端天气气候事件背景分析

利用北京市 1 951～ 2 0 0 1年 51年 7月下旬至 9月上旬的日最高气温、降水量、风、天气现象等观测资料 ,分别以旬为单位统计了高温、洪涝、大风、大雾、雷暴等对体育竞赛影响较大的极端天气气候事件发生的概率及分布特点 ,以期为 2 0 0 8年北京奥运会提供极端天气气候事件发生的气候背景资料。     

山西数字遥测地震台网各子台台址地脉动噪声分析

通过对山西数字遥测地震台网11个子台台址背景噪声进行分析和计算，得出了各台址背景噪声地脉动速度均方根值(RMS值)、观测动态范围、噪声信号功率谱。结果表明各台址背景噪声水平基本符合数字地震观测技术规范要求。     

成都市土壤测量Hg元素的发育特征及其来源

成都市是Hg的高背景和民异常区，深、浅层样各具不同的元素组合和发育特征。深层样Hg异常与构造、天然气、地热、矿产和基底隆起有关；浅层样则与城市居民生活，古代颜料、工业、燃煤、农业、河流的污染及上游的矿产等物质来源有关。     

Extragalactic source counts and contributions to the anisotropies of the cosmic microwave background: predictions for the Planck Surveyor mission

We present predictions for the counts of extragalactic sources, the contributions to fluctuations and their angular power spectrum in each channel foreseen for the Planck Surveyor (formerly COBRAS/SAMBA ) mission. The contribution to fluctuations owing to clustering of both radio and far-IR sources is found to be generally small in comparison with the Poisson term; however the relative importance of the clustering contribution increases and may eventually become dominant if sources are identified and subtracted down to faint flux limits. The central Planck frequency bands are expected to be 'clean': at high galactic latitude (| b | > 20°), where the reduced galactic noise does not prevent the detection of the extragalactic signal, only a tiny fraction of pixels is found to be contaminated by discrete extragalactic sources. Moreover, the 'flat' angular power spectrum of fluctuations resulting from extragalactic sources substantially differs from that of primordial fluctuations; therefore, the removal of contaminating signals is eased even at frequencies where point sources give a sizeable contribution to the foreground noise.     

The Planck Surveyor mission and gravitational lenses

An extremely sensitive all-sky survey will be carried out in the millimetre/submillimetre waveband by the forthcoming ESA mission Planck Surveyor . The main scientific goal of the mission is to make very accurate measurements of the spatial power spectrum of primordial anisotropies in the cosmic microwave background radiation; however, hundreds of thousands of distant dusty galaxies and quasars will also be detected. These sources are much more likely to be gravitationally lensed by intervening galaxies compared with sources discovered in surveys in other wavebands. Here the number of lenses expected in the survey is estimated, and techniques for discriminating between lensed and unlensed sources are discussed. A practical strategy for this discrimination is presented, based on exploiting the remarkable sensitivity and resolving power of large ground-based millimetre/submillimetre-wave interferometer arrays. More than a thousand gravitational lenses could be detected: a sample that would be an extremely valuable resource in observational cosmology.     

The background features of natural environment and the harnessing pattern for the spread of saline land in the Songnen Plain

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概率成像方法对地下球体定位的应用研究

概率成像方法是一种新颖的成像方法。它是利用测量的地面电场函数与电场扫描函数进行归一化的互相关运算，从而对地下电荷进行定位。本文对电法勘探中，地下球体进行了概率成像研究，给出了理论模型和成像结果，从而也证明概率成像方法确实是一种行之有效、计算简便的方法。