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doi: 10.1002/qj.49708737303pmid: N/A
The key to the understanding of the gross changes of climate throughout geological time indicated by the geological record in the various continents depends on finding a physical method of determining latitudes in the geological past. The palaeomagnetic method seems to be the most hopeful, but for this one must assume that the average geomagnetic field is a dipole along the axis of rotation. The palaeomagnetic evidence shows this to be true for late Tertiary times – the poles derived from the mean palaeomagnetic directions of Tertiary rocks cluster about the present geographical pole and are distinctly different from the present position of the magnetic pole. There are strong theoretical grounds for believing that it has been true throughout the earth's history. The theory of the irregular fluctuations in the length of the day indicates that the rotation of the core and mantle are only weakly coupled. The electro‐magnetic torque to which this coupling is ascribed is variable because of the short term changes in the geomagnetic field. These fluctuations appear to accumulate with time and so there is always a small differential angular velocity between core and mantle, probably of either sign. Therefore, to an observer fixed on the earth's crust, the earth's magnetic field is axisymmetrical when averaged over periods of the order of the secular variation, i.e., extremely small times geologically speaking.
doi: 10.1002/qj.49708737304pmid: N/A
A composite of Tiros 1 pictures describing the cloud system in a mature cyclone, centred in the Atlantic Ocean to the west of Ireland, is described. Comparison of the pictures with conventional meteorological data shows that a stratiform cloud surrounding the storm was identical in position with a warm moist tongue of air flowing around the storm. In the centre of the storm where the clouds were more broken, giving the appearance of cumuliform clouds, a large mass of cold, dry air extended from the surface up to the tropopause above 400mb. A few areas of steady precipitation were present in the stratiform cloud regions while more scattered showers existed in the central cumuliform region. An area of relatively high winds circled the storm, in conformity with the expectations from the thermal wind relation when cold air and warm air layers reside side by side. A brief comparison is made between the vertical motion computations based on conventional data and the cloud areas.
doi: 10.1002/qj.49708737305pmid: N/A
Stratospheric wind data for Canton and Christmas Islands show a fluctuation with a period of about 24 to 28 months in the zonal component. Christmas Island data also show that the fluctuation exists from below 60 mb to 10 mb (the highest level for which data are available) and that the amplitude of the fluctuation increases with height. The change in wind direction from W to E, or vice versa, is evident first at the higher levels and appears to work gradually downwards; at 60 mb the reversal of wind direction is evident about six months after that at 25 mb, and about twelve months after that at 10 mb.
doi: 10.1002/qj.49708737306pmid: N/A
An analysis is made of Project Jet Stream Research Flight No. 30, conducted on 8 April 1957. This flight made several traverses through a pronounced jet stream over the New England States. The fields of wind speed, potential temperature, vorticity and divergence are presented in vertical cross‐sections. Special reference is made to the differences between geostrophic and actual vertical wind shear in the vicinity of the jet core.
doi: 10.1002/qj.49708737307pmid: N/A
An account is given of some recent observations of solar‐radiation fluxes from aircraft of the Meteorological Research Flight. This account consists of two parts: 1 High‐level measurements of the albedo of the earth and atmosphere from a Canberra aircraft over southern England in 1958 and 1959, and over the Sahara Desert and Equatorial East Africa in June 1958 and January 1960. 2 Observations from a Hastings aircraft of the absorption and reflection of total and visible solar radiation from a cloud‐free atmosphere over the English Channel.
doi: 10.1002/qj.49708737308pmid: N/A
A method of computation of the direct absorption of solar radiation by the near infra‐red bands of water vapour and carbon dioxide in a cloudless, non‐scattering atmosphere using recent laboratory data compiled by Howard, Burch and Williams (1955) is described.
Bushby, F. H.; Whitelam, Clare J.
doi: 10.1002/qj.49708737309pmid: N/A
Subject to various approximations, a system of five simultaneous equations (three partial differential equations and two algebraic equations) is derived to predict the height of three contour surfaces corresponding to the bottom, middle and top of the troposphere and to evaluate the two fields of vertical motion corresponding to the upper and lower halves of the troposphere. The atmospheric model used is an extension of the two‐parameter model proposed by Sawyer and Bushby (1953).
doi: 10.1002/qj.49708737310pmid: N/A
The objective forecasting technique described consists of a composite diagram from which the forecast value of the predictand can be read directly, given the values of the predictors. Each section of the diagram combines a new predictor with an estimate of the predictand obtained from the previous sections. The isopleths in the diagrams are obtained by fitting a curved surface (involving powers and cross‐product terms of up to the fifth order) to the basic data by a ‘least squares’ procedure. Only terms which are significant at the 5 per cent level are retained in the regression formulae so produced. At each stage the predictor to be selected is that which contributes most to the combination so far chosen.
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