{"title":"The Saltzman-Lorenz Exchange in 1961: Bridge to Chaos Theory","authors":"John M. Lewis, S. Lakshmivarahan","doi":"10.1175/bams-d-23-0157.1","DOIUrl":null,"url":null,"abstract":"Abstract A single-day meeting between two theoretical meteorologists took place in 1961 at the Travelers Research Center (TRC) in Hartford, Connecticut. The two scientists were Barry Saltzman and Edward Lorenz, former proteges of V. P. Starr at MIT. Several years before this meeting, Lorenz discovered the following profound result: extended-range weather forecasting was not feasible in the presence of slight errors in initial conditions. The model used was the geostrophic form of a two-level baroclinic model with twelve spectral variables. These results were presented a year earlier at the First Symposium on Numerical Weather Prediction (NWP) in Tokyo, Japan, and met with some skepticism from the NWP elite, dynamical meteorologists, and pioneers in operational NWP. Lorenz held faint hope that Saltzman’s recently developed model of Rayleigh- Bénard convection would produce the profound result found earlier. One of the numerical experiments executed that eventful day with Saltzman’s 7-mode truncated spectral model produced an unexpected result: inability of the model’s 7 variables to settle down and approach a steady state. This occurred when the key parameter, the Rayleigh number, assumed an especially large value, one associated with turbulent convection. And further experimentation with the case delivered the sought-after result that Lorenz had found earlier, and now convincingly found with a simpler model. It built the bridge to chaos theory. The pathway to this exceptional result is explored by revisiting Saltzman’s and Lorenz’s mentorship under V. P. Starr, the authors’ interview with Lorenz in 2002 that complements information in Lorenz’s scientific autobiography, and the authors’ published perspective on Salzman’s 7-mode model.","PeriodicalId":9464,"journal":{"name":"Bulletin of the American Meteorological Society","volume":"127 1","pages":""},"PeriodicalIF":6.9000,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the American Meteorological Society","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1175/bams-d-23-0157.1","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METEOROLOGY & ATMOSPHERIC SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Abstract A single-day meeting between two theoretical meteorologists took place in 1961 at the Travelers Research Center (TRC) in Hartford, Connecticut. The two scientists were Barry Saltzman and Edward Lorenz, former proteges of V. P. Starr at MIT. Several years before this meeting, Lorenz discovered the following profound result: extended-range weather forecasting was not feasible in the presence of slight errors in initial conditions. The model used was the geostrophic form of a two-level baroclinic model with twelve spectral variables. These results were presented a year earlier at the First Symposium on Numerical Weather Prediction (NWP) in Tokyo, Japan, and met with some skepticism from the NWP elite, dynamical meteorologists, and pioneers in operational NWP. Lorenz held faint hope that Saltzman’s recently developed model of Rayleigh- Bénard convection would produce the profound result found earlier. One of the numerical experiments executed that eventful day with Saltzman’s 7-mode truncated spectral model produced an unexpected result: inability of the model’s 7 variables to settle down and approach a steady state. This occurred when the key parameter, the Rayleigh number, assumed an especially large value, one associated with turbulent convection. And further experimentation with the case delivered the sought-after result that Lorenz had found earlier, and now convincingly found with a simpler model. It built the bridge to chaos theory. The pathway to this exceptional result is explored by revisiting Saltzman’s and Lorenz’s mentorship under V. P. Starr, the authors’ interview with Lorenz in 2002 that complements information in Lorenz’s scientific autobiography, and the authors’ published perspective on Salzman’s 7-mode model.
摘要 1961 年,两位理论气象学家在康涅狄格州哈特福德的旅行者研究中心(TRC)举行了一次为期一天的会议。这两位科学家是巴里-萨尔茨曼(Barry Saltzman)和爱德华-洛伦兹(Edward Lorenz),他们曾是麻省理工学院 V. P. 斯塔尔(V. P. Starr)的门生。在这次会议召开的几年前,洛伦兹发现了以下深刻的结果:在初始条件存在微小误差的情况下,进行大范围天气预报是不可行的。所使用的模型是具有 12 个光谱变量的两级气压模型的地转形式。这些结果是一年前在日本东京举行的第一届数值天气预报(NWP)研讨会上提出的,当时受到了数值天气预报精英、动力学气象学家和实用数值天气预报先驱的怀疑。洛伦兹对萨尔茨曼最近开发的雷利-贝纳德对流模型能产生早先发现的深刻结果抱有微弱的希望。在那个多事的日子里,用萨尔茨曼的 7 模式截断谱模型进行的一次数值实验产生了一个意想不到的结果:模型的 7 个变量无法稳定下来并接近稳定状态。当关键参数雷利数的值特别大(与湍流对流有关)时,就会出现这种情况。进一步的实验证明了洛伦兹早先发现的结果,现在又令人信服地发现了一个更简单的模型。它架起了通向混沌理论的桥梁。通过重温萨尔茨曼和洛伦兹在 V. P. 斯塔尔门下的师徒关系、作者在 2002 年对洛伦兹的访谈(该访谈补充了洛伦兹科学自传中的信息)以及作者发表的关于萨尔茨曼 7 模式模型的观点,我们探索了通往这一非凡结果的道路。
期刊介绍:
The Bulletin of the American Meteorological Society (BAMS) is the flagship magazine of AMS and publishes articles of interest and significance for the weather, water, and climate community as well as news, editorials, and reviews for AMS members.