MM5模式中湿方案的不确定性对“03·7”南京暴雨数值模拟不确定性的影响

利用有限区域非静力MM5模式, 分析了显式降水方案对于2003年7月4—5日南京暴雨数值模拟的不确定性影响。采用混合方案模拟此次暴雨时, 这种不确定性决定于显式和隐式方案的相互协调性及敏感性; 隐式方案基本决定了雨带的整体的空间分布, 而显式方案对于降水型及降水量起到一定的调节作用, 调节的程度与选择的参数化方案有关; 采用隐式方案Grell和KF2模拟此次暴雨时, 应考虑不同的显式方案对于降水模拟的不确定性的影响。     

岩土参数不确定性的分析与评价

结合岩土工程实践的特点,定性分析参数不确定性的来源、分类、特征和处理方法,对认识岩土参数的变异性及概率极限状态设计准则的推广应用具有促进作用。     

LA‐(MC)‐ICP‐MS Trends in 2006 and 2007 with Particular Emphasis on Measurement Uncertainties

Research in 2006 and 2007 dealing with laser ablation‐(multicollector)‐inductively coupled plasma‐mass spectrometry, LA‐(MC)‐ICP‐MS, involved studies concerned with optimising the technique itself, as well as applying the method to a variety of problems in the Earth sciences. The causes of elemental and isotopic fractionation produced during laser ablation continues to be of considerable interest, with evidence mounting that processes occurring both at the ablation site and in the argon plasma of the ICP are culpable. There is growing excitement in the use of femtosecond lasers for LA‐(MC)‐ICP‐MS, with the hope that they reduce or eliminate melting and non‐congruent volatilisation at the ablation site and thus approach stoichiometric sampling. Ablation chamber design emerged as a serious concern, particularly with respect to achieving the rapid washout needed for fine‐scale compositional mapping of geological objects. LA‐MC‐ICP‐MS provided data for a wide range of isotopic systems, especially hafnium, but also B, S, Mg, Cu, Fe, Sr, Nd, Pb and U. Measurement uncertainties in LA‐ICP‐MS were discussed by several researchers, and are critically reviewed here ‐ total uncertainties for trace element concentration measurements of silicates including errors on the calibration values of common reference materials are ～10% (95% confidence limits), though the precision of individual spot measurements (50 to 100 μm) is much better, ～1% RSD, using a 193 nm laser and a sector field‐ICP‐MS. LA‐ICP‐MS U‐Pb ages for zircon and other U‐rich accessory phases are claimed by most geoanalysts to have 2s uncertainties of ～0.7 and 1.3% respectively but the actual accuracy of the method is probably only as good as ～2% (2s), when uncertainties associated with laser‐induced Pb/U fractionation are included.     

Methods for probabilistic assessments of geologic hazards

Although risk analysis today is considered to include three separate aspects (1) identifing sources of risk, (2) estimating probabilities quantitatively, and (3) evaluating consequences of risk, here only estimation of probabilities for natural geologic events, processes, and phenomena is addressed. Ideally, evaluation of potential future hazards includes an objective determination of probabilities that have been derived from past occurrences of identical events or components contributing to complex processes or phenomena. In practice, however, data which would permit objective estimation of those probabilities of interest may not be adequate, or may not even exist.Another problem that arises normally, regardless of the extent of data, is that risk assessments involve estimating extreme values. Probabilities are required for events that are the greatest or rarest because they commonly will have the greatest consequences; the largest, or rarest, events always fall in tails of frequency distributions. Rarely are extreme values accurately predictable even when an empirical frequency distribution is established well by data.In the absence of objective methods for estimating probabilities of natural events or processes, subjective probabilities for the hazard must be established through Bayesian methods, expert opinion, or Delphi methods. Alternative solutions may involve consequence analysis which may demonstrate that, although an event may occur, its consequences are sufficiently small that it safely may be ignored or by establishing bounds which may demonstrate that although probabilities are not known they cannot exceed a maximum value that is sufficiently small so that associated risk may be considered to be negligible.Uncertainty of every probability determination must be stated for each component of an event, process, or phenomenon. These uncertainties also must be propagated through the quantitative analysis so that a realistic estimate of total uncertainty can be associated with each final probability estimate for a geologic hazard.This paper was presented (by title) at Emerging Concepts, MGUS-87 Conference, Redwood City, California, 13–15 April 1987.     

BOOK REVIEWS

Book Reviewed in this article: Geographical Aspects of Health and Disease in India . Rais Akhtar and A.T.A. Learmonth , eds . Antarctic Treaty System: An Assessment . Proceedings of a Workshop at Beardmore South Field Camp, Antarctica. American Electoral Mosaics . J. Clark Archer and Fred M. Shelley . Kompas op Suidwes-Afrika/Namibie . W.S. Barnard , ed . Jerusalem in the 19th Century: The Old City . Yehoshua Ben -Arieh . The World as a Total System . Kenneth E. Boulding . A Social History of Housing 1815–1985, Second Ed . John Burnett . Human Migration . W.A.V. Clark . Regional Population Projection Models . Andrei Rogers . The State of Population Theory: Forward from Malthus . David Coleman and Roger Schofield , eds . Imagining Tomorrow: History, Technology and the American Future . Joseph C. Corn , ed. Swidden Agriculture in Indonesia: The Subsistence Strategies of the Kalimantan Kantú . Michael R. Dove . Glacial Geologic Processes . David Drewry . Physics of Desertification . Farouk El -Baz and M.H.A. Hassan , eds . Housing the Homeless . Jon Erickson and Charles Wilhelm , eds . Settlement Patterns in Missouri: A Study of Population Origins, with a Wall Map . Russel L. Gerlach . Desert Development: Man and Technology in Sparselands . Yehuda Gradus , ed . Nuclear Winter. The Evidence and Risks . Owen Greene , Ian Percival and Irene Ridge . The Take-off of Suburbia and the Crisis of the Central City . Günter Heinritz and Elisabeth Lichtenberger , eds . Regional Input-Output Analysis . Geoffrey J. D. Hewings . Spatial Transportation Modeling . Christian Werner . The Atlas of Georgia . Thomas W. Hodler and Howard A. Schretter , eds . Latin America. 5th ed . Preston E. James and C.W. Minkel . Applied Remote Sensing . C.P. Lo . Localities, Class, and Gender . The Lancaster Regionalism Group . Urban Social Movements: The City after Castells . Stuart Lowe . Politics and Method . Doreen Massey and Richard Meegan , eds . Land Use . A. S. Mather . The Kingdom of Coal . Donald L. Miller and Richard E. Sharpless . The Presidio and Militia on the Northern Frontier of New Spain, A Documentary History, Vol. 1: 1570–1700 . Thomas H. Naylor and Charles W. Polzer , S.J., comps . and eds . Nuclear Power: Siting and Safety . Stan Openshaw . The Central African Republic: The Continent's Hidden Heart . Thomas O'Toole . Environmental and Dynamic Geomorphology . Márton Pécsi , ed . Remote Sensing Principles and Interpretation . Floyd F. Sabins , Jr . Acid Rain and Friendly Neighbors: The Policy Dispute between Canada and the United States . Jurgen Schmandt and Hilliard Roderick , eds . Earth's Changing Surface: An Introduction to Geomorphology . M.J. Selby . International Migration: The Female Experience . Rita J. Simon and Caroline B. Brettell , eds . On Geography and Its History . D.R. Stoddart . Transportation Networks: A Quantitative Approach . D. Teodorovic . Processes in Physical Geography . R.D. Thompson , A.M. Mannion , C.W. Mitchell , M. Parry , J.R.G. Townshend . Imaging Radar for Resources Surveys . J.W. Trevett . Dominance and Affection: The Making of Pets . Yi -Fu Tuan . Capturing the Horizon. The Historical Geography of Transportation since the Transportation Revolution of the Sixteenth Century . James E. Vance , Jr . Nations at Risk: The Impact of the Computer Revolution . Edward Yourdon .     

Modelling radar-rainfall estimation uncertainties using elliptical and Archimedean copulas with different marginal distributions

Abstract

Given that radar-based rainfall has been broadly applied in hydrological studies, quantitative modelling of its uncertainty is critically important, as the error of input rainfall is the main source of error in hydrological modelling. Using an ensemble of rainfall estimates is an elegant solution to characterize the uncertainty of radar-based rainfall and its spatial and temporal variability. This paper has fully formulated an ensemble generator for radar precipitation estimation based on the copula method. Each ensemble member is a probable realization that represents the unknown true rainfall field based on the distribution of radar rainfall (RR) error and its spatial error structure. An uncertainty model consisting of a deterministic component and a random error factor is presented based on the distribution of gauge rainfall conditioned on the radar rainfall (GR|RR). Two kinds of copulas (elliptical and Archimedean copulas) are introduced to generate random errors, which are imposed by the deterministic component. The elliptical copulas (e.g. Gaussian and t-copula) generate the random errors based on the multivariate distribution, typically of decomposition of the error correlation matrix using the LU decomposition algorithm. The Archimedean copulas (e.g. Clayton and Gumbel) utilize the conditional dependence between different radar pixels to obtain random errors. Based on those, a case application is carried out in the Brue catchment located in southwest England. The results show that the simulated uncertainty bands of rainfall encompass most of the reference raingauge measurements with good agreement between the simulated and observed spatial dependences. This indicates that the proposed scheme is a statistically reliable method in ensemble radar rainfall generation and is a useful tool for describing radar rainfall uncertainty.

Editor D. Koutsoyiannis; Associate editor S. Grimaldi     

A Review on Shale Reservoirs as an Unconventional Play – The History, Technology Revolution, Importance to Oil and Gas Industry, and the Development Future

As a milestone of the entire energy industry, unconventional resources have inevitably swept the world in the last decade, and will certainly dominate the global oil and gas industry in the near future. Eventually, the “unconventional” will become “conventional”. Along with the rapid development, however, some issues have emerged, which are closely related to the viability of unconventional resources development. Under the current circumstances of low crude oil and gas price, coupled with the prominent environmental concerns, the arguments about the development and production of unconventional resources have been recently heated up. This work introduced the full-blown aspects of unconventional resources especially shale reservoirs, by discussing their concepts and definitions, reviewing the shale gas and shale oil development history and necessity, analyzing the shale plays’ geology and petroleum systems with respects to key hydrocarbon accumulation elements and mechanisms, and summarizing the technology resolution. This study also discussed the relevant key issues, including significant estimation uncertainty of technically recoverable resources, the equivocal understanding of complex geology preventing the production and technologies implementation optimization, the difficulties of experiences and technologies global expanding, and the corresponding risks and uncertainties. In addition, based on the latest production and exploration data, the future perspective of the unconventional resources was depicted from global unconventional resources assessments, technology development, and limitations constraining the development.     

非绝热物理过程对北京暴雨数值预报不确定性影响

选取了2001年8月发生于北京市的具有不同大尺度环流强迫特征的两次强降水过程,利用MM5模式和国家气象中心的T213预报资料,分析了模式非绝热物理过程对北京市暴雨数值预报的影响特征和不确定性,探讨了解决暴雨预报不确定性的集合预报方法,进行了多物理模式集合预报试验。试验结果表明:模式非绝热物理参数化方案对精细化预报结果有明显影响,包括局地降水强度、空间分布型态、时间演变特征等;在高分辨率模式中,采用积云对流参数化方案后,会出现更多的小量级降水预报,且不论是大尺度强迫较强的暴雨,还是大尺度强迫较弱的暴雨,对流参数化方案都是造成降水预报不确定性的重要因素。多物理集合预报的初步试验结果表明,高分辨率集合预报可提供有价值的预报信息,是解决灾害性天气预报不确定性的一种有效的技术方法,但就目前的模式水平而言,可重点发展降水集合预报,特别是强降水集合预报系统,以反映模式在降水预报中存在的不确定性。