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Marion W. Haurwitz
and
Glenn W. Brier

Abstract

Superposed epoch analyses, based on solar sector boundary crossings as key times and the Vorticity Area Index as the response variable, are tested for significance using both parametric and randomization techniques. We conclude from a comparison of these techniques that the randomization procedure leads to markedly different results from those obtained from parametric tests. In particular, the results are strongly affected by the modest skewness of the Vorticity Area Index distribution.

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Richard W. Knight
and
Glenn W. Brier

Abstract

Plans are underway to attempt to reduce the destructive force of hurricanes by artificially modifying their structure by means of cloud seeding. Since the natural variability of meteorological elements observed in hurricanes is high, the success of the project depends upon establishing a cause and effect relationship between the seeding and the hurricane's response. The small sample of mature hurricanes coupled with rigorous selection criteria make a randomized experiment impractical. Therefore, an evaluation technique based on the concept of randomization in time is developed.

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Glenn W. Brier
and
Gayle T. Meltesen

Abstract

The theorem of singular value decomposition is used to represent a data matrix X as the product of a system with a response R to a forcing function F. Algebraically, R is the matrix of principal components and F the transpose of the matrix of eigenvectors of X′X. If the data are such that the eigenvectors are orthogonal functions of time and they have some recognizable non-random structure permitting predictability in time, then the observed response at time t can be used with the extrapolated forcing function to predict some physical quantity (e.g., temperature, pressure). This method is called the time extrapolated eigenvector prediction (TEEP). An example is given to illustrate the method with a known forcing function, the annual solar heating cycle. We have access to efficient computer routines which will facilitate an extension to much larger data sets.

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Glenn W. Brier
and
Donald A. Bradley

Abstract

A cycle of 14.765 days, one-half of the lunar synodic month, can be demonstrated in the precipitation data for the United States for the period 1871–1961. Numerous rigorous statistical tests show that association is real and an estimate is obtained of the magnitude of the lunar effect. Geographical, seasonal and other sources of variation in the effect are suggested by the data. No other periodicity with comparable amplitude was found by the statistical analysis, but there is evidence that the lunar synodic cycle interacts with the nodical cycle.

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Glenn W. Brier
and
Isadore Enger

Abstract

No Abstract Available

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Glenn W. Brier
and
Isadore Enger
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Glenn W. Brier
and
Thomas Carpenter

Abstract

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DWIGHT B. KLINE
and
GLENN W. BRIER

Abstract

Daily freezing nuclei observations taken in the Washington, D. C., area during the first 3 months of 1958 showed large fluctuations in time relative to probable observational uncertainties. Anomalous values were detected around the January dates predicted by the meteoritic dust hypothesis. However, subsequent “peaks” do not appear to be associable with any known major meteor streams. A composite analysis of the dates of dominant peaks in similar observations a t a number of other locations since 1954 tends to confirm the existence of singularities in January which are statistically highly significant.

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DWIGHT B. KLINE
and
GLENN W. BRIER

Abstract

A brief description is given of a new refrigerated expansion chamber apparatus based on an Australian C.S.I.R.O. design for measuring ice nuclei concentrations. The compatibility of results between five instruments of similar construction, a comparison of data obtained with a simple version of the mixing chamber method, and homogeneity of rapid expansion measurements at sites 8 and 100 miles apart are investigated. Except for uncertainties regarding the extrapolation of results to natural clouds, all indications are that, with care, the nucleation level in the atmosphere is capable of objective, compatible measurement with standardized equipment. However, a series of measurements verified the existence of significant differences between the rapid expansion and mixing chamber techniques. Both methods reflected similar trends during appreciable increases or decreases in nucleation activity. A surprisingly uniform geographical distribution of aerosols responsible for ice crystal nucleation is suggested in some of the results.

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Paul W. Mielke Jr.
,
Kenneth J. Berry
, and
Glenn W. Brier

Abstract

This paper considers the examination of possible differences in monthly sea-level pressure patterns, The satisfactory examination of such differences requires appropriate multi-response parametric methods based on unknown multivariate distributions (i.e., an appropriate parametric technique is probably non-existent). In order to avoid the likely insurmountable difficulties involving parametric methods, the application of multi-response permutation procedures (MRPP) is suggested as an appropriate approach for the examination of such differences.

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