1.1 本指南提供了可用于将模拟空气浓度与观测到的现场数据进行比较的技术。这种比较提供了一种评估模型相对于其他候选模型的性能的方法，例如偏差和精度或不确定性。这种比较的方法仍在发展中；因此，随着这一领域工作的进展，统计测试、程序和数据分析将进行修改。在相关方就标准测试协议达成一致之前，将出现方法上的差异。本指南描述了一个框架或哲学背景，在这个框架或哲学环境中，人们可以确定一个模型的性能是否与其他候选模型显著不同。建议第一步应确定哪个模型的估计值平均最接近观测值，然后第二步将测试其他模型的性能差异是否与第一步中选择的模型显著不同。 中提供了一个示例过程 附录X1 以说明用于特定评估目标的现有方法。本示例并非旨在抑制将产生同等或卓越结果的替代方法或技术。如第节所述 6. ，模型性能的统计评估被视为一个更大过程的一部分，该过程统称为模型评估。 1.2 本指南的设计具有灵活性，可以扩展以解决可能涉及剂量或浓度波动的大气分散的各种特征，可以开发特定应用的评估方案，并可以使用各种统计比较指标。没有对模型表征色散的方式做出任何假设。 1.3 本指南的重点是最终结果，即模型预测的准确性和对模型之间差异是否显著的辨别，而不是操作细节，如模型实施的容易程度或执行模型计算所需的时间。 1.4 本指南提供了有组织的信息收集或一系列选项，不建议采取具体行动。本指南不能取代教育或经验，应与专业判断结合使用。并非本指南的所有方面都适用于所有情况。本指南并非旨在代表或取代判断特定专业服务是否充分的护理标准，也不应在不考虑项目许多独特方面的情况下应用本指南。本指南标题中的“标准”一词仅表示该文件已通过ASTM共识程序批准。 1.5 本标准适用于高斯羽流模型；它可能不适用于非点源、水池蒸发产生的重气体模型（例如，液体泄漏）以及近场受体。 1.6 以国际单位制表示的数值应视为标准。 本指南不包括其他计量单位。 1.7 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ===意义和用途====== 5.1 为设计模型评估性能程序以及大气中分散的随机性导致的模型性能统计评估中出现的困难提供了指导。 众所周知，文献中有一些例子，在知情或不知情的情况下，对模型描述其从未打算描述的事物的能力进行了评估。本指南旨在提高人们的认识，从而减少“不知情”的比较次数。本指南的目标是促进评估程序的开发和测试，以适应自然变异的影响。说明了一种提供信息的技术，从中可以得出后续的评估和标准化。

1.1 This guide provides techniques that are useful for the comparison of modeled air concentrations with observed field data. Such comparisons provide a means for assessing a model's performance, for example, bias and precision or uncertainty, relative to other candidate models. Methodologies for such comparisons are yet evolving; hence, modifications will occur in the statistical tests and procedures and data analysis as work progresses in this area. Until the interested parties agree upon standard testing protocols, differences in approach will occur. This guide describes a framework, or philosophical context, within which one determines whether a model's performance is significantly different from other candidate models. It is suggested that the first step should be to determine which model's estimates are closest on average to the observations, and the second step would then test whether the differences seen in the performance of the other models are significantly different from the model chosen in the first step. An example procedure is provided in Appendix X1 to illustrate an existing approach for a particular evaluation goal. This example is not intended to inhibit alternative approaches or techniques that will produce equivalent or superior results. As discussed in Section 6 , statistical evaluation of model performance is viewed as part of a larger process that collectively is referred to as model evaluation. 1.2 This guide has been designed with flexibility to allow expansion to address various characterizations of atmospheric dispersion, which might involve dose or concentration fluctuations, to allow development of application-specific evaluation schemes, and to allow use of various statistical comparison metrics. No assumptions are made regarding the manner in which the models characterize the dispersion. 1.3 The focus of this guide is on end results, that is, the accuracy of model predictions and the discernment of whether differences seen between models are significant, rather than operational details such as the ease of model implementation or the time required for model calculations to be performed. 1.4 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This guide is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should it be applied without consideration of a project's many unique aspects. The word “Standard” in the title of this guide means only that the document has been approved through the ASTM consensus process. 1.5 This standard applies to gaussian plume models; it may not be applicable to non-point sources, heavy gas models from evaporation from pool (for example, liquid spills), as well as near-field receptors. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this guide. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Guidance is provided on designing model evaluation performance procedures and on the difficulties that arise in statistical evaluation of model performance caused by the stochastic nature of dispersion in the atmosphere. It is recognized there are examples in the literature where, knowingly or unknowingly, models were evaluated on their ability to describe something which they were never intended to characterize. This guide is attempting to heighten awareness, and thereby, to reduce the number of “unknowing” comparisons. A goal of this guide is to stimulate development and testing of evaluation procedures that accommodate the effects of natural variability. A technique is illustrated to provide information from which subsequent evaluation and standardization can be derived.