Artificial earth srttellites offer a unique opportunity t o exploit the possibility of deducing temperature profiles on a global scale from measurements of radiance in several narrow spectral intervals in A strongly absorbing band of an atmospheric gas whose mixture is uniform. In the earth's atmosphere the 4.3-micron and 15-micron bands of carbon dioxide and the 5-mm. band of oxygen may be used; only the 15-micron band is considered in detail, although the procedures are applicable to the other bands. The Woblem considered is the numerical solution of the integral form of the radiative transfer equation from measurements in a finite set of spectral intervals. It is shown that, by a suitable approximation of the Planck radiance, the radiative transfer equation can be reduced to an integral equation of the first kind. After a discussion of the kernel, which is associated with the transmittance of the gas, the equation is changed to a finite set of equations which is amenable to numerical solution. The solution is limited to about six pieces of information, which may be expressed as points along the vertical profile, or as coefficients of an expansion; the limitation in information is manifest in the transmittance curves for the several spectral intervals, the errors of measurement, and the approximations employed. However, even in this limited case the formal solution of the set of equations is unstable. I n this process the amount of smoothing remains small, so that the inherent properties of the temperature profile are not affected. Several possible 351 352

Observations from aircraft of the Meteorological Research Flight flying near stratocumulus clouds showed steep inversions and hydrolapses directly above the tops of the clouds. Turbulence was encountered below and in the clouds and up to 300 ft above the cloud top. Above this level no turbulence was encountered. Analysis of the heat and water‐vapour budgets of the cloud and air below suggests that the cloud and the profiles of temperature and humidity can only be maintained if there is large‐scale subsidence. The effects of subsidence, outgoing radiation and turbulent transfer are all comparable.

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SUMMARYA description is given of one flight below cumulus clouds on 28 Aug. 1952. Small rapid fluctuations of temperature were observed by a sensitive resistance thermometer, records being obtained as a photographic trace. It is shown that, with respect to the frequency and type of fluctuation of temperature encountered, the space between cloud base, i.e., 3,100 ft, and ground level may be divided into three sections. The first, a layer extending from ground to about 800 ft, the second from 800 ft to about 2,800 ft, and the third from 2,800 ft to cloud base. A possible explanation for the formation of these layers is discussed.

SUMMARYA technique is described for determining the three-dimensional field of vertical air motion in the vicinity of mobile fronts. Radar reflectors are dropped from an aircraft at a height of 5 km and followed by high precision tracking radars. By making assumptions regarding the movement and conservativeness of the frontal system it has been possible to use this technique to obtain horizontal winds over a volume approximately 150 x 100 x 4 km depth with a typical drop separation of 30 km. Using the equation of continuity, vertical velocities have been calculated with an uncertainty of f 1 -2 cm s-l. In a warm front investigated on 19 January 1969, close agreement was obtained between the rainfall observed at the surface and that computed from the vertical velocities assuming saturation of the rising air.