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71.
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Forecasting in the social and natural sciences: An overview and analysis of isomorphisms 总被引:1,自引:0,他引:1
This article identifies and analyzes several points of similarity in the structure and context of forecasting in the social and natural sciences. These include: the limits of identities or universal laws as a basis for forecasts; the corresponding need for simplifying parametric representations of one or more of the variables that enter into identities; various sources of uncertainty about parameterizations; intrinsic limitations on predictability or forecasting accuracy in large-scale systems; the need for sensitivity analyses of model responses to changes in exogenous variables and/or parametric structures; problems of model linkage; and the social (organizational and political) context of forecasts. Suggestions for future lines of inquiry are made in each case. Several of these are such that they can benefit from a sharing of experience and expertise across disciplinary lines.The research reported herein was supported in part by the IC2 Institute, The University of Texas at Austin, and in part by National Science Foundation Grant Number SES-8411702. However, the opinions expressed in the paper are those of the authors and do not necessarily reflect those of the sponsoring organizations. We appreciate the advice and comments of Jesse H. Ausubel, Robert S. Chen, Judith Jacobsen, and Richard C. Rockwell on earlier versions of this paper.The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
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The orientation of the regional stress field in the Swabian Jura was determined from borehole breakouts caused by stress accumulation at the borehole wall. The analysis is based on caliper data recorded in the Urach 3 geothermal well within an intervall of about 1450 m. The azimuths of the breakouts are consistent with depth and indicate a stress direction which is in good agreement with the interpretation of fault plane solutions of nearby earthquakes. 相似文献
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Further Studies Of Atmospheric Turbulence In Layers Near The Surface: Scaling The Tke Budget Above The Roughness Sublayer 总被引:2,自引:0,他引:2
The second of two experimental studies of the TKE budget conducted on sites of different roughness is described, and results are compared. The first took place within a shallow layer above a small field of mostly bare, cultivated soil; the second was carried out above a roughness sublayer of significant depth on an extensive plain of tall dry grass. Budget terms observed in the second study were scaled with a modified u which compensated for effects of an unusually large stress gradient and ensured that the m functions would be collinear. By showing that the modification becomes negligible in smaller gradients, it is demonstrated that in normal conditions, budgets observed above significant roughness sublayers should be normalized by scaling in terms of the unreduced Reynolds stress at the sublayer's upper surface. This procedure is shown to be consistent with the expectation that TKE budgets in layers near the surface all scale in fundamentally the same way.Other findings include: (1) the fact that most m functions previously reported are not quite collinear is attributed to a type of overspeeding known to affect three-cup anemometers; (2) revised m functions, collinear and largely free of the effects of overspeeding, are determined from a well-established characteristic of the linear m relation for the stable case; (3) data that define collinear m functions can also be represented with single hyperbolic curves; (4) dissipation is found to be 10 to 15% too small to balance total TKE production in unstable and neutral conditions and to decrease with increasing z/L in thestable regime; and (5) new relations for based on the observed behaviour of the dissipation deficit provide an improved closure for the set of equations that express the budget terms as functions of m and z/L. 相似文献
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A simple two-domain bucket model of fractured soil was coupled with a stochastic model of rainfall variability, in order to investigate the climate and soil controls upon the stochastic properties of the triggering of fracture flow and surface runoff, and the partitioning of rainfall between the matrix and fracture domains and surface runoff. Conventionally, soils are regarded as time domain filters between rainfall and hydrological response. This investigation highlights an additional type of threshold filtering especially important in understanding the infiltration behaviour of fractured soils, for which an event-based characterisation of rainfall in modelling is crucial. A priori-definable indices were derived which are capable of describing elements of this threshold filtering, by allowing the statistical properties of fracture flow- and surface runoff-triggering storms (i.e., mean and variance of storm duration, intensity and effective inter-storm period, as well as cumulative partitioning of rainfall), to be inferred directly from average storm and soil properties. Using these indices, the long-term response of fractured soils, including the long-term hydrological importance of fractures, can be estimated without simulation. 相似文献