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- Author or Editor: John F. Griffiths x
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Abstract
There has been a rapidly growing awareness in the past few years of the role that the atmospheric scientist can play in assisting the architect to achieve a structure that is designed for, and not in spite of, the climate. The concept of a comfortable cryptoclimate is developed, and the recent history of the intercommunication between the disciplines is discussed. Some examples of basic ideas developed from studies of primitive architecture are cited also. The outline of a course in meteorology, specifically designed for architectural students, that has been taught at Texas A&M University for nine years is described together with certain relevant observations and techniques. Some of the more surprising findings in this interdisciplinary field are detailed.
Abstract
There has been a rapidly growing awareness in the past few years of the role that the atmospheric scientist can play in assisting the architect to achieve a structure that is designed for, and not in spite of, the climate. The concept of a comfortable cryptoclimate is developed, and the recent history of the intercommunication between the disciplines is discussed. Some examples of basic ideas developed from studies of primitive architecture are cited also. The outline of a course in meteorology, specifically designed for architectural students, that has been taught at Texas A&M University for nine years is described together with certain relevant observations and techniques. Some of the more surprising findings in this interdisciplinary field are detailed.
Abstract
An analysis of the possible differences among various rainfall parameters during drought and nondrought periods was undertaken for 12 Texas stations. The division of monthly rainfall amounts into quintiles served as the rainfall classification. Rainfall amounts, number of rains and rainfall intensities were calculated for each quintile for four thresholds of rainfall 0.0254, 0.2540, 0.5080 and 1.2700 cm. The thresholds were applied on a daily and hourly basis. At low rainfall thresholds in nearly every case, numbers of rains in very dry periods proved to be <100% of normal.
The possible differences in persistence of rainfall during Very Dry and Very Wet periods were examined by calculating runs of rains of 0.0254 cm or more per hour. Medians of runs of rain hours in Very Dry periods were found to be less than those in Very Wet periods except at Corpus Christi in April and at Waco in February. Probabilities that a run of rain hours would extend to a given length were determined. During Very Dry periods a probability >0.5 that a rain will extend into a second hour during a month of key importance to agriculture (June, July and August) occurs only at Amarillo, Lovelady, Port Arthur and Waco. The probability that a rain will extend into a third hour is never above 0.5 during the key months in Very Dry periods for any of the stations studied.
The implications of these findings are discussed in relation to feasibility of cloud seeding and to irrigation management during severe drought.
Abstract
An analysis of the possible differences among various rainfall parameters during drought and nondrought periods was undertaken for 12 Texas stations. The division of monthly rainfall amounts into quintiles served as the rainfall classification. Rainfall amounts, number of rains and rainfall intensities were calculated for each quintile for four thresholds of rainfall 0.0254, 0.2540, 0.5080 and 1.2700 cm. The thresholds were applied on a daily and hourly basis. At low rainfall thresholds in nearly every case, numbers of rains in very dry periods proved to be <100% of normal.
The possible differences in persistence of rainfall during Very Dry and Very Wet periods were examined by calculating runs of rains of 0.0254 cm or more per hour. Medians of runs of rain hours in Very Dry periods were found to be less than those in Very Wet periods except at Corpus Christi in April and at Waco in February. Probabilities that a run of rain hours would extend to a given length were determined. During Very Dry periods a probability >0.5 that a rain will extend into a second hour during a month of key importance to agriculture (June, July and August) occurs only at Amarillo, Lovelady, Port Arthur and Waco. The probability that a rain will extend into a third hour is never above 0.5 during the key months in Very Dry periods for any of the stations studied.
The implications of these findings are discussed in relation to feasibility of cloud seeding and to irrigation management during severe drought.
Abstract
Ten stations are chosen for a study of climatic variability in the continental United States, using as the main criteria good geographical distribution, long-period records (since before 1900), and available daily, monthly and annual values of maximum and minimum temperatures and precipitation. Regression lines of decadal variances calculated from annual temperature indicate significant trends of variances, and thus variability, at several stations. A slight increase in precipitation variability is evident across the entire region.
Analyses of ranked monthly maximum and minimum temperatures reveal several distinct discontinuities in the data. In most instances, station relocations coincide with the discontinuities.
Abstract
Ten stations are chosen for a study of climatic variability in the continental United States, using as the main criteria good geographical distribution, long-period records (since before 1900), and available daily, monthly and annual values of maximum and minimum temperatures and precipitation. Regression lines of decadal variances calculated from annual temperature indicate significant trends of variances, and thus variability, at several stations. A slight increase in precipitation variability is evident across the entire region.
Analyses of ranked monthly maximum and minimum temperatures reveal several distinct discontinuities in the data. In most instances, station relocations coincide with the discontinuities.
Abstract
This study examines the relationship between cloud-to-ground (CG) lightning and surface precipitation using observations from six regions (each on the order of 10000 km2), April through October (1989–93), in the south-central United States. The relationship is evaluated using two different methods. First, regression equations are fit to the data, initially for only the CG lightning flash density and precipitation, and then with additional atmospheric and lightning parameters. Second, days are categorized according to differences in the precipitation-to-CG lightning ratio; the same additional parameters are then examined for differences occurring within each category.
Results show that the relationship between CG lightning and surface precipitation is highly variable; r2 coefficients range from 0.121 in Baton Rouge to 0.601 in Dallas. A measure of the positive CG lightning flash density is the best addition to the model, statistically significant in all regions. When days are categorized, the percentage of lightning that is positive shows the most significant differences between categories, ranging from <4% on days with a “low” precipitation-to-CG lightning ratio, to 12%–36% on days with a “high” ratio. Other lightning parameters give less significant results; however, three atmospheric parameters (CAPE, lifted index, and Showalter index) do show a significant trend suggesting that there is much less instability in the atmosphere on “high” ratio days than on “low” ratio days.
Abstract
This study examines the relationship between cloud-to-ground (CG) lightning and surface precipitation using observations from six regions (each on the order of 10000 km2), April through October (1989–93), in the south-central United States. The relationship is evaluated using two different methods. First, regression equations are fit to the data, initially for only the CG lightning flash density and precipitation, and then with additional atmospheric and lightning parameters. Second, days are categorized according to differences in the precipitation-to-CG lightning ratio; the same additional parameters are then examined for differences occurring within each category.
Results show that the relationship between CG lightning and surface precipitation is highly variable; r2 coefficients range from 0.121 in Baton Rouge to 0.601 in Dallas. A measure of the positive CG lightning flash density is the best addition to the model, statistically significant in all regions. When days are categorized, the percentage of lightning that is positive shows the most significant differences between categories, ranging from <4% on days with a “low” precipitation-to-CG lightning ratio, to 12%–36% on days with a “high” ratio. Other lightning parameters give less significant results; however, three atmospheric parameters (CAPE, lifted index, and Showalter index) do show a significant trend suggesting that there is much less instability in the atmosphere on “high” ratio days than on “low” ratio days.
