CORRESPONDENCE of Bosanquet's measurements whereas Meade appears to have fitted c to the measurements themselves and even allowed a different range of values for each plant. I still feel that we must reserve judgment on which of the working theories gives the most accurate results until experimental data are available over a wider range.One object behind my analysis was to promote, in conjunction with observations of the rise of plumes, measurements of their spreading and of atmospheric turbulence, for it seems clear that there is no unique relation between these two, and that each will strongly affect the plume's elevation. Any claim to provide even an approximate treatment dispensing with one of these parameters, or its equivalent, must therefore be open to suspicion on that very account.But Meade of course does not really reduce to a ' single parameter c ' for he requires to assume values for both p and zo/Rp It is agreed that his analysis is the less elaborate when it comes to the computation of an actual example, but this is scarcely a serious consideration. Graphical or numerical integration is required in any event, and the problem is of sufficient importance to warrant the calculations being carried out once and for all to cover the relevant range of conditions.My main objection to Meade's treatment is that it turns its back on certain issues which were raised in mine, and which were there at least set on the road towards their resolution. Eq. (1) gives w as a monotonic decreasing function of z , and so excludes any case in which vertical motion is generated by buoyancy, e.g., the plumes from smoke-pots used in frost protection. Neither this nor the preceding formula contain the plume temperature or Froude number, and they therefore imply that all plumes with the same wo, Ro, zo will follow the same path, however hot they are. No indication is given of how to apply the formula when the environment is thermally stratified; presumably this might be done by adjustingp, but what are the guiding principles ?Finally it is seen from the complete solution in the M.R.P., Eq. (13), that the Eq. (3) of that paper is not satisfied : this equation here represents the condition that the temperature regime shall be in a steady state. The solution therefore does not apply to the steady state, nor indeed is it the solution of any properly formulated problem because only two basic equations have been given for the three independent variables R, 8, w.In order to extend the range of experimental data my colleague, F. K. Ball, has made measurements of plumes from burning oil-pots under a variety of wind speeds. At the larger distances downwind the smoke was too disperse to measure accurately, but at shorter distances the heights agreed very well with my theory (first phase). Thus the tentative formula Eq. (5) of my paper stands up well, without change of the constant of proportionality, to a considerable change in scale and boundary conditions. We have little evidence at all about the second phase, and the limitations of my t...

A new-comer to the subject of meteorology, browsing over its literature, particularly its dynamical and thermodynamical literature, might be excused for forming the opinion that the theoretical meteorologist was hoping to account for the evolution of the atmosphere in terms of adiabatic transformation of a frictionless system. Perhaps the meteorologist is able to make substantial progress in his study within these constricting limits. Certainly the less complex system is worthy of study before the more complex. But we all, of course, know that we should have no weather to study and that we should not be here to study anything if the atmosphere had no heat sources or sinks and were devoid of friction.The signs are in fact appearing that even in those fields where the adiabatic assumption has proved least restricting, as in the dynamical study of large-scale systems, models must begin to be more realistic thermodynamically, and to possess friction. Old problems, such as the general circulation, in which heat and momentum transfer are at the heart of the matter, are also now being treated afresh. I thought therefore that it would be opportune to consider the problem of the transfer of heat, momentum and matter in the atmosphere. I shall restrict myself to transfer in the vertical but even this problem is too large to be adequately discussed in the time available and I must ask your indulgence if I deal only with some aspects which have particularly interested me or about which I feel able to say something to the point. I shall start at the earth's surface but I hope to climb well into the atmosphere before I stop. My attitude will be unashamedly practical. The theory of transfer processes in the atmosphere is in the most rudimentary state, far more so than for example the dynamical theory of large-scale motions (themselves a part of the transfer problem), and were I to confine myself to well-argued theory I should have little to say. But I believe there is now a substantial body of knowledge on transfer which can be expressed in terms consistent with such theory as we possess, well tried in experience and therefore applicable. Man did not wait to fly until he had created a theory of flight, but, by flying encouraged the development of theory, with consequent feedback. Meteorology is a more difficult study than aeronautics but we too can try our wings and expect similar results. TRANSFER AT THE EARTH'S SURFACE

were confirmed and extended to include the region 4 -12 p.Unexpectedly high absorption was observed in this latter region.(ii) These results inspired a reexamination of all available previous work, from which it was concluded that the extinction arises from two separate effects with different frequency and temperature dependence.They are i) a foreignbroadened component, roughly proportional to the foreign gas pressure and probably positively temperature dependent (0.5 to 1% per °C); and ii) a self-broadened component roughly proportional to partial vapour pressure and with a strong negative temperature dependence (2% per °C at 30°C).On the basis of several assumed line shapes, the accumulated wings of lines in the 50 la rotation band were computed at several points in the range 12 -40 p; the Lorentz shape gave a very good fit (1. 10%) to the foreign-broadened component, but none gave a satisfactory fit to the selfbroadened component. *The 15 11 CO2 band was found to give no detectable absorption (< 1% for 43 atm -cm of CO 2' the equivalent of 1.4 km of air at sea level) outside the range 12.7 to 17.8 11.The horizontal path experiment has already been reported in a joint paper with F. Saiedy and P. A. Sheppard, entitled 'On the Atmospheric Infrared Continuum', J.O.S.A. 51, 466 (1963); a copy is attached to this thesis.During this research a further paper, on the related topic of terrestrial heat balance, entitled 'Heat-balance measurements from an earth satellite -an analysis of possibilities' was published in Quart. J. Roy. Met. Soc., 87, 231 (1961); a copy is attached. 11.13 See Addendum for amended version. ,Chapter 1?1. IntroductionThe existence of a continuous absorption throughout the atmospheric infrared window between 8 and 13 microns has been knoinfor a long time, Elsasser (1938) probably being the first to draw attention to it. It has been observed many times since by all workers in the study of atmospheric radiation, both in transmission observations using the sun and artificial sources, and in emission studies from ground and space 2.iii) Since the advent of artificial earth satellites, several infrared emission experiments have been proposed, or in some cases already been carried out, to determine the earth's surface temperature distribution, cloud top height, ozone and carbon dioxide distribution, and temperature structure in the upper atmosphere.All of these, except possibly the last, require correction to some extent for the continuum.Much discussion has centred on the question of the origin of the continuum absorption; there is no doubt that it is largely due to wcter vapour, but the role of aerosol is less certain. That it is necessary to appeal to something other than water vapour appears to be due to the fact that measurements of continuum absorption by different workers do not seem to be consistent when compared on the basis of the existing picture of the water vapour continuum alone. Whilst it is not disputed that aerosol absorption in the 8 -13j. region can be significant under extremel...

SUMMARYObservations of wind speed and direction at 50 m intervals of height in the first few hundred metres have been made over the NE. Atlantic during 10 winter days of westerly winds. The following results were obtained :The vertical gradient of wind speed is of the same order at all levels and there is no identifiable transition from a layer of frictional influence to a layer of friction-free wind.The wind speed at 300 m was on the average 21 per cent greater than the surface wind, though in 2 1 per cent of cases the latter was greater than the former. The mean change of direction in the same interval of height was 3.6" veer but the spread was much greater than the mean. On over 30 per cent of cases the wind at 300 m was backed on the surface wind and the speed at the upper level was then only 5 per cent greater than the surface speed.(iii) The vector variation of wind velocity with height in the layer 200-500 m is accountable as thermal wind.(iv) Turbulence of scale greater than about 10 min is of order 10 per cent of the mean motion and increases on average with height.(v) The mean inclination of the surface wind to the isobar is not more than 1 ' or 2" and is more likely to be towards high pressure than low.It is inferred that the classical conception of the frictional boundary layer in a barotropic atmosphere has little validity in the atmosphere over the sea. In particular the shearing stress in the first few hundred metres of the westerlies probably varies only slightly with height and may increase if the thermal wind is strong. Measurement of surface drag by the method of frictional geostrophic departure is hardly possible in the baroclinic westerlies.(i)(ii)