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- Author or Editor: R.R. DICKSON x
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Due to its utility in handling joint functions, the method of coaxial graphical correlation is used to relate particulate air pollution at Nashville, Tennessee to various meteorological factors. The derived relationship applied to test data yielded an average absolute error of 38.3 micrograms per cubic meter and root-mean-square error of 59.3; these results are clearly superior to a climatological control forecast using seasonal average concentrations. Graphical analysis and supporting correlation-ratio computations suggest that small amounts of precipitation may be very effective in cleansing particulate matter from the atmosphere, rendering further precipitation of little consequence. The analysis emphasizes the importance of wind direction in governing air-pollution concentrations at a point, suggesting that point measurement of particulate concentrations may have little representativeness when applied to an area the size of a city. Particulate-matter concentration is found significantly correlated with day of the week (weekday-weekend groupings), offering an avenue for improvement of results.
Due to its utility in handling joint functions, the method of coaxial graphical correlation is used to relate particulate air pollution at Nashville, Tennessee to various meteorological factors. The derived relationship applied to test data yielded an average absolute error of 38.3 micrograms per cubic meter and root-mean-square error of 59.3; these results are clearly superior to a climatological control forecast using seasonal average concentrations. Graphical analysis and supporting correlation-ratio computations suggest that small amounts of precipitation may be very effective in cleansing particulate matter from the atmosphere, rendering further precipitation of little consequence. The analysis emphasizes the importance of wind direction in governing air-pollution concentrations at a point, suggesting that point measurement of particulate concentrations may have little representativeness when applied to an area the size of a city. Particulate-matter concentration is found significantly correlated with day of the week (weekday-weekend groupings), offering an avenue for improvement of results.
Abstract
In view of the interrelated nature of component parts of the atmospheric circulation, it is suggested that surface-atmosphere interaction studies should be hemispheric in scope for time intervals beyond a few days. Hemispheric data sources for potentially important surface conditions—sea-surface temperature, snow cover, sea-ice extent, and soil moisture—are discussed and an example of the extent of such data as are readily available is given. This example is discussed in conjunction with the evolving circulation pattern in terms of the origin of anomalous surface conditions and their possible effects. The role of anomalous surface features in relation to November to December climatological persistence is discussed for two regions on the basis of conditions in November and December 1959.
Abstract
In view of the interrelated nature of component parts of the atmospheric circulation, it is suggested that surface-atmosphere interaction studies should be hemispheric in scope for time intervals beyond a few days. Hemispheric data sources for potentially important surface conditions—sea-surface temperature, snow cover, sea-ice extent, and soil moisture—are discussed and an example of the extent of such data as are readily available is given. This example is discussed in conjunction with the evolving circulation pattern in terms of the origin of anomalous surface conditions and their possible effects. The role of anomalous surface features in relation to November to December climatological persistence is discussed for two regions on the basis of conditions in November and December 1959.
The variation of certain climatic elements with elevation is examined for Tennessee-North Carolina portions of the Southern Appalachian region. Regression equations relating elevation to annual, January, and July mean temperatures and mean daily temperature ranges and to length of growing season are derived. Early growing-season data for 15 mountain-valley systems in western North Carolina are examined and regression lines developed relating length of growing season to elevation for valley and summit locations. These regression lines adjusted for departure of early data from long-term averages appear applicable to recent long-term data and present a useful means of refining the growing season-elevation relationship. Although a satisfactory precipitation-elevation relationship is unattainable due presumably to slope and exposure effects, an estimate is given of the mean annual snowfall-elevation relationship. Graphs are presented showing the variation of potential evapotranspiration with elevation based on computations for selected locations from 1075 ft to 6684 ft; results are believed representative of the entire area under consideration.
The variation of certain climatic elements with elevation is examined for Tennessee-North Carolina portions of the Southern Appalachian region. Regression equations relating elevation to annual, January, and July mean temperatures and mean daily temperature ranges and to length of growing season are derived. Early growing-season data for 15 mountain-valley systems in western North Carolina are examined and regression lines developed relating length of growing season to elevation for valley and summit locations. These regression lines adjusted for departure of early data from long-term averages appear applicable to recent long-term data and present a useful means of refining the growing season-elevation relationship. Although a satisfactory precipitation-elevation relationship is unattainable due presumably to slope and exposure effects, an estimate is given of the mean annual snowfall-elevation relationship. Graphs are presented showing the variation of potential evapotranspiration with elevation based on computations for selected locations from 1075 ft to 6684 ft; results are believed representative of the entire area under consideration.
Abstract
Map analyses are provided depicting the probability of snow-cover 1 inch or more in depth at the end of each month from September through May for the Northern Hemisphere.
Abstract
Map analyses are provided depicting the probability of snow-cover 1 inch or more in depth at the end of each month from September through May for the Northern Hemisphere.
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WEATI-IER AND CIRCULATION OF AUGUST 1974
Relief from Heat and Drought in the Central United States
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Abstract
Satellite-augmented observations of tropical storm and hurricane frequencies in the southeastern North Pacific during recent Augusts (1966–1974) were compared to various environmental factors. On a regional scale, a relatively strong mean 700 mb ridge from the Gulf of Mexico to Baja California was found to accompany high storm frequency. The linear correlation coefficient between storm frequency and a measure of the strength of this ridge amounted to 0.77. On a larger scale, the 700 mb Subtropical Westerlies Index (20°N to 35°N) for west longitudes from 0° to 180° had a somewhat stronger relation to storm frequency (r=0.86). Average August sea surface temperature in the vicinity of storm formation was poorly correlated with storm frequency. This suggests that the unfailingly warm August water temperatures in this area— always exceeding 27°F—were not a limiting factor in storm development.
Abstract
Satellite-augmented observations of tropical storm and hurricane frequencies in the southeastern North Pacific during recent Augusts (1966–1974) were compared to various environmental factors. On a regional scale, a relatively strong mean 700 mb ridge from the Gulf of Mexico to Baja California was found to accompany high storm frequency. The linear correlation coefficient between storm frequency and a measure of the strength of this ridge amounted to 0.77. On a larger scale, the 700 mb Subtropical Westerlies Index (20°N to 35°N) for west longitudes from 0° to 180° had a somewhat stronger relation to storm frequency (r=0.86). Average August sea surface temperature in the vicinity of storm formation was poorly correlated with storm frequency. This suggests that the unfailingly warm August water temperatures in this area— always exceeding 27°F—were not a limiting factor in storm development.
Abstract
Monthly values of the anomaly of percent possible sunshine at 21 locations in the United States were related to the field of monthly mean 700 mb height anomaly by correlation and regression analysis. Data were generally for the 1950–69 period, grouped by seasons. Reduction in variance afforded by the derived multiple linear regression equations, averaged over all locations and seasons, was 0.47 for the development data sample. In general, results were best over the western half of the nation and poorest along the eastern seaboard. Correlation fields and multiple linear regression equations relating percent possible sunshine at Memphis, Tenn., to the field of monthly mean 700 mb height anomaly are discussed in detail.
Abstract
Monthly values of the anomaly of percent possible sunshine at 21 locations in the United States were related to the field of monthly mean 700 mb height anomaly by correlation and regression analysis. Data were generally for the 1950–69 period, grouped by seasons. Reduction in variance afforded by the derived multiple linear regression equations, averaged over all locations and seasons, was 0.47 for the development data sample. In general, results were best over the western half of the nation and poorest along the eastern seaboard. Correlation fields and multiple linear regression equations relating percent possible sunshine at Memphis, Tenn., to the field of monthly mean 700 mb height anomaly are discussed in detail.
