400 NEWELL AND MILLER lower troposphere. In a recent contribution*4 they find that watervapor transport in middle latitudes is governed by eddy processes, whereas in the tropics the Hadley cell is dominant in the production of an equatorward flux. SEASONAL CHANGES IN MASS TRANSFER AND ENERGETICS At the previous AEC fallout conference, it was demonstrated that the quasi-horizontal eddy processes that carry ozone poleward vary in intensity and accomplish a maximum transport in the early part of the year, The computations have since been extended, and Table 2 shows the combined covariance results for 16 stations in Europe between Table 2— OZONE MERIDIONAL WIND COVARIANCE AT THE 100-MB LEVEL WITH THE NUMBER OF CASES IN PARENTHESES Centimeters of ozone at S.T.P. x cm/sec Year 1957 1958 ; 1959 Average January-March April—June 10.29 (908) —2,.49 (1185) 9.44 7.63 (424) July—September October— December 3.63 (829) 4.40 (887) 2.29 (646) 4.38 (638) 8.81 (519) —0.80 3.33 2.60 (1261) 5.12 (1077) 5.63 30 and 60°N. The covariance is between total ozone amounts and 100-mb meridional wind. It has also been demonstrated that the standing-wave contribution to the ozone flux is of comparable size to the transient-eddy contribution in middle latitudes and has a similar seasonal variation.*® If these processes also bring more radioactive material down into the troposphere, then one can argue that the spring maximum in fallout is due to an increase in magnitude of the large~scale mixing processes in the lower stratosphere during the early part of the year. Of course, this will be coupled to the seasonal change in large-scale mixing processes which also occurs in the 25- to 30-km region and in layers above. The extra eddy-mixing of ozone in the lower stratosphere may be brought about by inclined motions that are more steeply inclined in the early part of the year than at other times. Air parcels would thus suffer greater vertical displacements in their passage through the large-scale wave pattern. With this type of mechanism, it can be shown’ that a potential-energy increase will occur at the expense of kinetic energy; therefore the supply of energy to the region from the troposphere must also increase. Insofar as this vertical flux may depend on the amplitude of the standing waves in the troposphere, ac-