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Maurice E. Graves

The temperature field from 9 km to 19 km at San Juan is studied by means of measuring the slopes of 12-hourly sounding curves and drawing tropopause and temperature anomaly patterns on time scales. Two distinct tropopause types are found and these are termed primary and secondary tropopauses.

A rainfall index is computed as a measure of convective activity and it is compared with changes in tropopause pressure and temperature. The secondary tropopause sinks to a minimum elevation with large rainfall maxima.

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MAURICE E. GRAVES

Abstract

Special high-level cloud observations from two commercial jet air lines are used to estimate the vertical distribution of cirriform clouds. One year's data are summarized graphically for certain high-latitude routes and the California-Honolulu sector. Tropopauses in very high latitudes are occasionally exceeded in height by cirrus. Tropical tropopause levels are consistently 5 km. or more above the cirrus tops reported between Honolulu and the California coast.

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W. Gale Biggs
and
Maurice E. Graves

Abstract

Since the mathematical equations describing the lake breeze phenomenon are too complex to yield exact solutions, approximation techniques are often used. To obtain the important parameters upon which the solutions depend, a dimensional analysis is then employed. The study shows that two dimensionless parameters describe the balance of forces that distinguish between lake breeze days and non-lake breeze days. A lake breeze index is established and a critical value is found. It a narrow transition zone is recognized, then the lake breeze index has an accuracy of 97 per cent.

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Maurice E. Graves
and
Morris Perlmutter

Abstract

To illustrate the effective use of meteorological data in the planning of spacecraft launchings, certain statistical relationships are presented based on Markov theory and empirical counts. The practical results are in terms of conditional probability at Kennedy Space Center, and are based on 15 years of recorded summer weather data which are analyzed under a set of natural environmental launch constraints.

Three specific forecasting problems are treated: 1) the length of record of past weather which is useful to a prediction, 2) the effect of persistence on runs of favorable and unfavorable conditions, 3) the forecasting of future weather in probabilistic terms. The first problem yields the order of the operative Markov chain, the second problem offers an opportunity to compare theoretically derived results on runs with experimental counts, and the third problem permits application of the Chapman-Kolmogorov equations to obtain conditional probabilities for unfavorable launch conditions up to 4 days in the future. A link is provided between such general conditions and the probability that a launch will be delayed at any specific afternoon hour.

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MAURICE E. GRAVES
and
EDWARD S. EPSTEIN

Abstract

With the future utilization of new-type upper tropospheric observations in mind, the estimation of 500-mb. geopotential height from 300-mb. data is accomplished by least squares regression. The regression coefficients form latitudinal patterns which can be expressed by linear relationships in low latitudes and parabolic relationships else-where. From three year's mid-seasonal-month grid data, measures of extrapolation error are obtained over half of the Northern Hemisphere. Verifying tests with radiosonde station data indicate that the error in low latitudes is substantially due to analysis noise in the 500-mb. grid data.

When the same techniques are applied to 200-mb. information, further error studies show considerably less feasibility of extrapolation from that level to 500 mb. However, the temperature at 200 mb. is found to be valuable in predicting the simultaneous temperature at 500 mb.

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