Papers in Physical Oceanography and Meteorology
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Published by the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution. Published originally as Massachusetts Institute of Technology Meteorological Papers (1930-1932), this collection contains papers from Vol .1 No. 1 to Vol. 10 No. 4 (1930-1948).
ISSN: 0198-6821
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Browsing Papers in Physical Oceanography and Meteorology by Subject "Atmospheric temperature"
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BookReport on an experiment in five-day weather forecasting(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1940-04) Allen, R. A. ; Fletcher, R. ; Holmboe, J. ; Namias, Jerome ; Willett, Hurd C.The following report is presented as a statement of progress made at the Massachusetts Institute of Technology (M.I.T.) in the investigation into the possibility of extending the range of reliable weather forecasts. This project has been supported at M.I.T. and other private institutions by Bankhead-Jones appropriations since September, 1937. This report is concerned only with the work completed or in progress at M.I.T. The complementary program now in progress at the Weather Bureau in Washington is referred to only in so far as it has contributed directly to these investigations. Furthermore, the following report refers only to the last two years of the M.I.T. project. The first year of the three-year project was given over principally to the study of the results obtained by long range forecast methods already in use, and to the establishment of a northern hemisphere synoptic weather map procedure as a necessary precedent to the preparation of weekly forecasts on a synoptic basis. The results of the M.I.T. study of certain long range forecast methods already in practice are included in a general survey of such methods already published. The synoptic charts prepared at M.I.T. during that first year of the investigation are listed in an appendix to this report, together with those of the last two years. The preparation of weekly forecasts carried on during a part of that first year was so experimental in nature, and the procedure was so much changed the following year, that the results obtained were considered neither suffciently significant nor comparable enough with the later forecast results to merit any discussion. The present report is divided into three principal sections. Section I presents in condensed form our present conception of the essential nature of the general circulation, and discusses briefly the background of one or two of Professor Rossby's theoretical considerations concerning the general circulation which have found statistical and synoptic application in this investigation. Section II contains in brief form the results of synoptic and statistical checks of a large number of hypothetical relationships which might be assumed to hold in the earth's atmosphere. These include possible relationships in the large scale features of the general circulation, relationships between the general circulation and its different branches or centers of action, between the different branches or centers of action of the general circulation, between characteristics of the general circulation or its branches and anomalies of the meteorological elements in certain regions, between anomalies of the meteorological elements in one region and those in another region, and even between solar activity (sunspots) and characteristics of the general circulation or anomalies of the meteorological elements. The aim was to investigate possible interrelationships of all kinds, either with or without lag, in order to detect as many interaction principles or points as possible in the earth's atmosphere, whether they had direct or only the most indirect bearing on the forecast problem. The relationships investigated applied to daily, weekly, monthly, seasonal, or annual mean conditions. They were selected for investigation either from theoretical or practical considerations of the nature of the general circulation as outlined in Section I, or on the basis of popular beliefs which have long been current among meteorologists, or on the basis of direct observation of data which looked promising. The majority of these hypothetical relationships are found to be quite weak when subjected to rigid statistical checks, but all such results, whether positive or negative, are summarized in this report. Section III outlines the five-day forecast routine practice which has been carried on at M.I.T. during the greater part of the past two years on a weekly basis. It includes a statistical analysis of the verification results. In the conclusion are summarized the results of the investigation which thus far appear significant enough to justify their consideration in five-day or longer range forecasts. Suggestions are offered as to further steps which might profitably be taken if the investigation is to be continued. Finally there is an appendix in which are listed all the daily synoptic maps and mean charts and diagrams of surface and upper air data which have been plotted and analyzed at M.I.T. in connection with this project during the past three years. The importance of such a list is apparent when it is realized that inevitably in an investigation of this kind much the greater part of the time and effort expended is consumed in the routine or semiroutine duties involved in the preparation of such charts.
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BookA study of interdiurnal pressure and temperature variations in the free atmosphere over North America(Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1946-08) Malone, Thomas F.The three-dimensional distribution of pressure and its variation with time are intimately associated with the principal weather phenomena. However, this association is indirect rather than direct and the link connecting the two is the horizontal and vertical field of motion. The relationship between the field of motion and the variation in time and space of pressure is one of interdependence. On the other hand, the field of motion seems causally related to most weather phenomena. Neither of these relationships is fully understood so it is not surprising that current attempts to utilize pressure distributions as tools for predicting weather phenomena do not meet with complete success. In this connection, the variation of pressure with time is of prime interest, inasmuch as it reflects physical processes currently in operation in the atmosphere and as it presages future developments. Study of these processes through an analysis of pressure variations is complicated by the compressibility of the atmosphere and by the observed fact that mass variations of either sign may be taking place within any layer in the atmosphere quite independently of variations of the mass within any other layer. Since the instantaneous distribution of pressure and its variation with time are hydrostatically related to the temperature field and its changes, it is advantageous to study the two elements simultaneously. Any consideration of the temperature field in the atmosphere inevitably requires that some attention must be devoted to the tropopause as a major first order discontinuity of temperature. Moreover, the significance of this general reglon of the atmosphere as a location of processes important in determining tropospheric pressure variations has been stressed by the Austrian School of Meteorologists. The problem of achieving a better understanding of the nature of pressure changes may be attacked in one or more of three different, though complementary ways - theoretically, descriptively, and/or, statistically. The theory has been discussed by Stüve, Defant, V. Bjerknes, J. Bjerknes, Solberg, and Bergeron, and more recently by Wulf and Obloy, J. Bjerknes and Holmboe, and Petterssen, as well as by others. The descriptive approach by means of detailed analyses of selected situations has been demonstrated in many investigations all over the world, among which are several particularly interesting studies in North America and Europe. The statistical treatment was first attempted by Dines and Schedler and considerably extended and refined by Haurwitz and others and by Penner. The statistical studies mentioned above have been based upon an analysis of mean conditions and mean changes in vertical columns of air assumed to be in hydrostatic equiiibrium. Since the problem is essentially dynamic, such analyses can never present the complete picture of the physical processes involved in pressure changes. However, in view of the present unsatisfactory state of knowledge concerning these processes, such statistical studies play an extremely valuable role in improving the general understanding of the complex systems of mass variations which are integrated into pressure changes by the atmosphere. They present mean conditions against which descriptive and theoretical studies may be evaluated with regard to representativeness and applicability, respectively. Furthermore, they are systematic summaries of actual conditions which may properly serve as a guide to the direction in which further theoretical and descrptive investigations may most profitably proceed. The paucity of upper air data has restricted the scope of previous studies along these lines and so it is the aim of this investigation to utilize the information recently available as a result of the well organized network of radiosonde observation stations in North America to extend these studies. In particular, it is desired to investigate the geographical and seasonal differences in the mean values of pressure and temperature variation at all levels and the related upper air conditions. It is hoped that the greater number of observations in the stratosphere may throw some light on its true importance with respect to tropospheric pressure variations and that mean conditions throughout the lower atmosphere may be so defined that it will be possible to set up certain requirements which any proposed mechanism for pressure changes must satisfy in order to be thoroughly consistent with reality. The observational material and the methods of analysis will be discussed in Chapter I. Chapters II, III, and IV will be devoted to a description of the results of the statistical analysis. Since the interpretations of one aspect of the study depend upon the results of some of the other aspects, most of the interpretations and conclusions wil be discussed in Chapter V.