Hurd C. Willett
Published: 1962
Total Pages: 37
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Introduction: The study of long-term solar-climatic relationships was selected as the primary investigation of NSF Grant 5931, which terminated in September, 1960. As explained in the final report of that project, submitted on October 4, 1960, this investigation was planned originally to consist essentially of three phases, namely: 1. The solar phase - the comparative study of monthly mean values of a number of selected indices of solar activity, for as long a period as satisfactory records are available, to serve as a basis for the selection of a number of key solar indices for comparison with key indices of climatic conditions. 2. The climatic phase - the use of monthly mean northern hemisphere sea-level pressure data and of 500-mb or 700-mb pressure contour data, covering the period 1899-1960 inclusive, for the comprehensive characterization of the patterns of monthly mean departures from normal of wind and temperature over the northern hemisphere by calendar months. 3. The solar-climatic phase - the determination from 1 and 2 of any characteristic patterns of departure from normal of monthly mean wind or temperature over the northern hemisphere in relation to solar activity. Phase 1 of this investigation was completed and sunmarized briefly in Scientific Report No. 1, published by NSF Grant 5931 in September 1960, under the Title "Long-Term Indices of Solar Activity." Most of the routine processing of monthly climatic data necessary for phase 2 of the investigation was completed under 5931, with some assistance from the U. S. Weather Bureau - M. I. T. Extended. Forecasting Project, as described briefly in the Final Report for 5931, submitted in October 1960. All of the necessary extensive statistical analysis of the selected climatic indices, together with the final phase 3 of the planned investigation, remained untouched at the termination of NSF Grant 5931 at the end of September 1960. At this point the investigation was taken over by NSF Grant 14077. Phase 2 of the investigation will be essentially completed by this scientific report, which discusses briefly the results of the extensive statistical analysis of the selected climatic indices, as a preliminary to phase 3. At the present time work is progressing steadily on phase 3 of the investigation. Frustrating delays have been experienced, caused partly by a seven-week period of closing down of the available computing facilities, and partly by some obstinate programming difficulties in the involved statistical correlation program. However, the program appears now to be running smoothly on the recently installed IBM 7090, so that the initial statistical results on phase 3 are beginning to come in. The statistical analysis of the solar-climatic relationships which constitutes this third phase of the investigation will be based partly on correlation of the selected solar index and circulation parameter indices, and partly on superposed epoch techniques applied to selected cases. The superposed epoch approach will be facilitated by the fact that all of the necessary data will exist in normalized form on punch cards. It is hoped that this culminating final phase of the investigation will be essentially completed by early autumn, in time for a concluding scientific report and for the final report on NSF Grant 14077. The ultimate application to operational long-range forecasting of any useful practical information about solar-climatic relationships which may be derived from this investigation was at no time considered to be an objective of the NSF project. If the results obtained by this investigation appear to justify practical prognostic application, that application probably will be made by the U. B. Weather Bureau - M. I. T. Extended Forecasting Project.