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arXiv 1102.2846physics.ao-phphysics.data-an
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4d- VAR在灾害性天气应急预报中的潜力

Potential of 4d-VAR for exigent forecasting of severe weather

Ross N. Hoffman, John M. Henderson, Thomas Nehrkorn

摘要:

强烈的风暴、热带气旋以及与之相关的龙卷风、洪水、闪电和微暴流威胁着生命和财产。对这些现象的可靠、精确和准确的警报可以触发防御行动和准备。然而,这些重要的天气现象很难预测。本文的目的是证明4d-VAR(四维变分资料同化)的强风暴前兆的紧急预报(XF)的潜力,从而表征一个最坏的情况下的概率。4d-VAR的目的是调整数值天气预报模式的初始条件(IC)与IC的先验估计的不确定性一致,同时最大限度地减少现有观测的失配。对于XF,采用相同的方法,但不是拟合观测值,而是最大化或最小化损坏或损失或等效代理的度量。为了实现这一目标,需要为4d-VAR开发一个专门的成本函数。当4d-VAR解决XF问题时,副产品将是背景成本函数的值,该值提供了预测紧急情况发生的可能性的度量。4d-VAR已被应用于飓风修正研究中XF的一个特例。作为XF的原型,对1992年安德鲁飓风的个例研究进行了总结。XF的研究预计将推进高影响天气事件的预报,改进向受威胁人口传达紧急天气事件的警报和潜在影响的方法,可扩展到商业上可行的产品,如预测柑橘产业的冻结,并成为有用的教学工具。

英文摘要:

Severe storms, tropical cyclones, and associated tornadoes, floods, lightning, and microbursts threaten life and property. Reliable, precise, and accurate alerts of these phenomena can trigger defensive actions and preparations. However, these crucial weather phenomena are difficult to forecast. The objective of this paper is to demonstrate the potential of 4d-VAR (four dimensional variational data assimilation) for exigent forecasting (XF) of severe storm precursors and to thereby characterize the probability of a worst-case scenario. 4d-VAR is designed to adjust the initial conditions (IC) of a numerical weather prediction model consistent with the uncertainty of the prior estimate of the IC while at the same time minimizing the misfit to available observations. For XF the same approach is taken but instead of fitting observations, a measure of damage or loss or an equivalent proxy is maximized or minimized. To accomplish this will require development of a specialized cost function for 4d-VAR. When 4d-VAR solves the XF problem a by-product will be the value of the background cost function that provides a measure of the likelihood of occurrence of the forecast exigent conditions. 4d-VAR has been previously applied to a special case of XF in hurricane modification research. A summary of a case study of Hurricane Andrew (1992) is presented as a prototype of XF. The study of XF is expected to advance forecasting high impact weather events, refine methodologies for communicating warning and potential impacts of exigent weather events to a threatened population, be extensible to commercially viable products, such as forecasting freezes for the citrus industry, and be a useful pedagogical tool.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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