Glenn W. Brier

Application of Multi-Response Permutation Procedures for Examining Seasonal Changes in Monthly Mean Sea-Level Pressure Patterns

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.

A Critique of the Superposed Epoch Analysis Method: Its Application to Solar–Weather Relations

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.

Lunar Synodical Period and Widespread Precipitation

Precipitation activity over broad areas appears to be closely associated with the monthly lunisolar cycle. Indexes of precipitation in the continental United States over a continuous 50-year period, and 91-year daily histories of individual stations, reveal that heavy rains occur most frequently in the first and third weeks of the synodical month.

The Quasi-Biennial Oscillation and Feedback Processes in the Atmosphere-Ocean-Earth System

Abstract Recent investigations indicate that the quasi-biennial oscillation (QBO) in stratospheric winds may be related to variations in the tropospheric circulation in middle and high latitudes. Although the QBO was noticed years ago in a number of worldwide atmospheric phenomena, it is still not well understood. A logical question arises as to whether the oscillation might be a result of the annual forcing by the solar heating, since it is well known that in some nonlinear systems subharmonic oscillations can be produced of order one-half the frequency of the exciting force. A conceptual model is presented to show how a two-year oscillation could be produced by a negative feedback process acting on a two-state system, i.e., winter and summer states. Even for a relatively weak biennial oscillation with stochastic elements involved, the results show that rather strong links must exist in the chain or feedback loop, indicating potential predictability for periods of six months or more. Support for the conc...

The Lunar Synodical Period and Precipitation in the United States

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.

A Statistical Reanalysis of the Replicated Climax I and II Wintertime Orographic Cloud Seeding Experiments

Abstract A reanalysis of the Climax I and II experiments is described. The concern prompting this reanalysis is a suggestion arising from Colorado State University analyses of extended area effects. Those analyses suggested a regionwide pattern of precipitation that, by chance, may have favored the randomly selected seeding days for some of the important meteorological partitions used in earlier analyses. In order to address this concern, this reanalysis employs excellent covariate relationships developed before the initiation of Climax II and which account for over half of the target variability for most meteorological partitions of major interest (e.g., warm 500 mb temperatures and southwest 700 mb wind directions). The statistical evidence of seeding-induced increases for this reanalysis is generally much stronger than in the previous analysis, which did not utilize covariates. For example, the joint one-sided Wilcoxon test statistic P-value for testing the null hypothesis that seeding did not induce a...

Stormfury Cumulus Seeding Experiment 1965: Statistical Analysis and Main Results

Abstract A randomized seeding experiment was carried out on 23 tropical oceanic cumulus clouds on 9 days in the summer of 1965 as part of the joint Navy-ESSA Project Stormfury. Following instructions in sealed envelopes, an aircraft seeded 14 of the clouds with 8-16 pyrotechnic silver iodide generators called Alecto units. Each unit releases about 1.2 kg of silver-iodide smoke. The nine remaining clouds were studied in an identical manner as controls, using the same stack of four instrumented aircraft to penetrate the cloud before and after the seeding run. Cloud growth was documented by aircraft, radar and photogrammetry. The seeded clouds grew vertically an average of 1.6 km more following the seeding run than did the control clouds; the difference is significant at the 0.01 level. A numerical model of cumulus dynamics was specified in advance of the field program. This model integrates the equation for the vertical acceleration of an entraining cumulus tower, predicting top heights of unseeded and seed...

DIURNAL AND SEMIDIURNAL ATMOSPHERIC TIDES IN RELATION TO PRECIPITATION VARIATIONS1

Abstract Evidence is presented that precipitation variations in the United States are related to the solar and lunar tidal forces. The results of the statistical investigation are consistent with a mathematical model that shows how a small periodic influence can be of possible importance for the timing of an event such as the initiation of precipitation.

SOME EXPERIMENTS ON THE MEASUREMENT OF NATURAL ICE NUCLEI1

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 sugges...

Ocean Water as a Source of Ice Nuclei

Preliminary tests indicate that ocean water may release an abundance of ice nuclei to the atmosphere. These results may explain the observation that marked anomalies often accompany an influx of marine air in the Washington, D. C., area and the fact that abnormal counts are often associated with widespread precipitation.