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Systematic measurements of isotopic tracers in the atmosphere, particularly tritium, deuterium, and oxygen 18 in water vapor, are for practical reasons largely restricted to samples obtained at ground level. On the other hand, their use as atmospheric tracers requires as complete a knowledge as possible of their sources and sinks as well as of their distribution and transport patterns (in space and time) in the atmosphere. In their paper, Schell et al. [1970] attempt to develop a model that permits combination of isotope measurements in ground-level samples with meteorological parameters of the three-dimensional atmosphere in order to calculate the desired tracer distribution and transport values. In this particular case, the authors determine the tracer injection into the moist tropospheric layer (surface to 500 mb) from above.

This article reviews the information on the climatic effect of carbon dioxide and aerosols and outlines man's part in contributing to their occurence. Recent downward trends in the average surface temperature of the biosphere has lead some scientists to conclude that albedo increases due to the effect of aerosol backscatter is the causative mechanism. While there is evidence for and against this hypothesis, this paper emphasizes that albedo changes due to aerosol modification of cloud cover may be a more significant mechanism for explaining temperature trends.

An extensive series of lidar measurements of plume rise at Northfleet Power Station (effective stack height 120 m) fits the formula of L ucas et al. (1963): Z max = αQ + U , where α is 500 m2 sec−1 MW−+, Z max = plume rise (m), Q = heat emission (MW) and U = wind speed (m sec −1 ) . Measurements of plume rise at Tilbury Power Station made with a modified cloud-base searchlight are also in reasonable agreement with the formula.

Measurements of temperature, humidity, turbulence, wind speed and direction on a 187 m high tower are described. Particular attention is paid to the presence of stable layers and their effect on the turbulence.

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It is shown that the dissimilar nature in the solar cycle variations in the three major competing ionizing sources for the D-region (e.g. X-rays below 8A, Lα and cosmic rays) can be used to provide an estimate for the concentration of the neutral nitric oxide at and near 70 km. Use of the electron density profiles recently given by D eeks (1965) for sunspot minimum and maximum conditions for equinox in middle latitudes give a nitric oxide concentration of 4 × 105/cm3 around 72 km, about one hundredth of Barth’s rocket-deduced value. When this value is integrated with currently available photochemical information, the following empirical distribution is indicated: n ( NO ) = 2 × 10 − 2 exp ( − 3300 T ) n ( O 2 ) + 5 × 10 − 7 n ( O ) .

Noting the direction of the wind is part of the regular routine of observations at the Observatory on the summit of Ben Nevis. Owing to the frequency of frozen fogs in winter, anemometers are practically useless, but the record is made complete enough for many purposes by the hourly observations; at each hour of the day and night the wind, at the time of making the observation, is noted, and the number of entries of each wind direction in the day, month, or year must very nearly represent the relative frequency of such winds for that time. Table I. is a summary giving the number of times each wind is observed in each month of the year on an average of six years (1884–89) expressed in percentages; thus in January, out of the 744 hours of the month, there are 120 hours or 16·1 per cent, of N. wind. For the year the most frequent wind is N., next come S.W., S.E., and S., all about equal, and the least frequent is E. N. is the point of greatest frequency in all months except May, when S.E. takes its place; in May 1889 there were only 15 hours in the whole month with N., N.W., or N.E. winds, and during three-fourths of that month the air was moving from the S. or S.E. This was, of course, an exceptional month, but in the six years there are only two (1887–88) in which N. was the most frequent wind in May.

The basis of existing national and international standards for derating naturally aspirated and turbo-charged diesel engines for temperature, altitude, and humidity is recapitulated. The effect of site ambient conditions on the permissible rating of modern turbo-charged and charge-air cooled engines, with fixed and rematched turbo-chargers, is discussed. The effect of turbo-charger and charge-air cooler limitations on the engine rating is examined, including the use of air-to-air charge cooling. Consideration is given to the installation details which affect the engine performance, e.g. air-intake temperature, cooling water, etc.

Night-time variations of the OH nightglow intensity reported by Wiens and Weill are compared with the theoretical predictions of a number of models. The behaviour of this emission agrees better with the theoretical one for locations in the equatorial zone but becomes more variable and less predictable for mid-latitude stations. It is calculated that, as a result of an increase of the eddy diffusion coefficient K, the OH emission can deviate from the typical night-time variation and increase by a factor as high as 2 if K is multiplied by 10. It is suggested that the eddy diffusion coefficient in the upper atmosphere is lower and undergoes lower amplitude variations in the equatorial zone than in the mid-latitude regions.

The quasi-periodic 27-day variations ƒ 0 E at Washington are significantly related to corresponding variations of the sunspot number.

In their recent paper Drevinsky et al. [1964] question the validity of our conclusion [Bleichrodt, 1962; Bleichrodt and van Abkoude, 1963] that Be7 was produced artificially by the Soviet tests of nuclear weapons in the autumn of 1961. They suggest that the more or less linear relationship observed between the concentrations of Be7 and Sr89 in the lower stratosphere might be the (fortuitous) result of sampling air originating at higher altitudes and latitudes which is expected to contain higher concentrations of both cosmic-ray-produced Be7 and, shortly after nuclear tests in polar regions, higher concentrations of fission products. Although the explanation of Drevinsky et al. cannot be disproved unequivocally, it should be considered very unlikely for the following reasons.

Critique of paper on water crystal existence on Venus, presenting arguments against existence of clouds of micron sized ice crystals

Some of the observational evidence which leads to the conclusion by Layzer and Bedinger (1969) that the small scale structure of high altitude vapor trails is not produced by preexisting atmospheric turbulence is recalled briefly in response to the recent report by Lloyd, Low and Vincent (1973). Specifically noted are: the difference in the structure of the ‘up’ and ‘down’ trails, the delay in appearance of the globular structure, and the equal frequency of occurrence of globules in regions of low and high wind shear. It is concluded that the observation presented by Lloyd, Low and Vincent does not alter our conclusion which is based on a large number of trails.

Epstein et al. [1965] present data on deuterium and oxygen 18 variations with depth in South Pole precipitation, in which the seasonal alternation of isotopic highs and lows is a measure of the accumulation rate. Deuterium and oxygen 18 variations in fresh precipitation from all climatic regions are linearly correlated [Friedman, 1953; Craig, 1961a], so that the depth profiles for the two isotopes are identical as expected. Although one isotope is therefore sufficient to provide accumulation data, as noted by the authors the isotopic relationships are very important for the study of the meteorological and climatic regimes controlling precipitation. It is this aspect of their data which I wish to discuss.

companying figure. The 28.4-3, surface field calculated by RING is within 13% of 32.4-3, field predicted using Sckopke's relation and an equatorial dipole field of 0.31 gauss. This correction decreased the magnetic moment of the quietday ring current from 0.26 M• to 0.21 Ms, 86% of which is contained by the low-energy protons (E _( 50 key). On this basis the subsolar magnetic field would be decreased by 4%, and the required solar wind density would be decreased by about 8%. However, this correction also increased the size of the nondipolar component near 11 R• to more than 10% of the dipole field. In summary, these small offsetting changes