Search Results
Abstract
Mean radiosonde observations and normal maximum surface temperatures are used with the assumption of a dry adiabatic lapse rate to estimate monthly mean maximum mixing depths (MMD's) for 45 stations in the contiguous United States. From these data isopleth analyses of mean MMD's are presented for each mouth. Deviation from the assumption of a dry adiabatic lapse rate is discussed. Sixteen of the available 45 radiosonde stations are selected as generally representative of the United States and are subjected to further considerations. These considerations are (1) the relationship between monthly mean MMD's computed from mean observations and from individual observations, (2) comparison of monthly mean MMD's based on observations for 1 year with those based on observations for 10 years, and (3) the standard deviations of daily MMD's.
Abstract
Mean radiosonde observations and normal maximum surface temperatures are used with the assumption of a dry adiabatic lapse rate to estimate monthly mean maximum mixing depths (MMD's) for 45 stations in the contiguous United States. From these data isopleth analyses of mean MMD's are presented for each mouth. Deviation from the assumption of a dry adiabatic lapse rate is discussed. Sixteen of the available 45 radiosonde stations are selected as generally representative of the United States and are subjected to further considerations. These considerations are (1) the relationship between monthly mean MMD's computed from mean observations and from individual observations, (2) comparison of monthly mean MMD's based on observations for 1 year with those based on observations for 10 years, and (3) the standard deviations of daily MMD's.
Abstract
Daylight visibility observations at the Sacramento Municipal Airport were used to investigate the possibility that visibility in the area has been declining due to rising levels of air pollution. Those visibility observations made with naturally occurring fog (defined as relative humidity greater than 90 percent) and/or precipitation were eliminated from the data. Observations for July, a warm, dry month with relatively slight climatic differences from year to year, and November, a cool month that often exhibits it considerable annual variation of climate, were tabulated for the three 4-year periods, 1935–38, 1945–48, and 1953–56. The results show that for July the percent frequency of poor visibilities steadily increased, and of good visibilities steadily decreased over the last 20-odd years. Such a trend is consistent with the Sacramento population increase. For November the trend was irregular. This is believed to be due to variations in the occurrence of meteorological factors, important to atmospheric dispersion. It is likely that such irregularities are characteristic of other months and areas where there are large annual climatic variations.
From concurrent surface wind observations, the preferred wind conditions for various visibility ranges were determined. These data indicate that poor visibilities at the airport, on the southern edge of the city, occurred most frequently with light winds from over the nearby Sacramento urban area. Good visibilities were favored by moderate winds from rural directions. Visibilities were reduced when the wind speed became strong enough for loose materials to be picked up from the ground.
Abstract
Daylight visibility observations at the Sacramento Municipal Airport were used to investigate the possibility that visibility in the area has been declining due to rising levels of air pollution. Those visibility observations made with naturally occurring fog (defined as relative humidity greater than 90 percent) and/or precipitation were eliminated from the data. Observations for July, a warm, dry month with relatively slight climatic differences from year to year, and November, a cool month that often exhibits it considerable annual variation of climate, were tabulated for the three 4-year periods, 1935–38, 1945–48, and 1953–56. The results show that for July the percent frequency of poor visibilities steadily increased, and of good visibilities steadily decreased over the last 20-odd years. Such a trend is consistent with the Sacramento population increase. For November the trend was irregular. This is believed to be due to variations in the occurrence of meteorological factors, important to atmospheric dispersion. It is likely that such irregularities are characteristic of other months and areas where there are large annual climatic variations.
From concurrent surface wind observations, the preferred wind conditions for various visibility ranges were determined. These data indicate that poor visibilities at the airport, on the southern edge of the city, occurred most frequently with light winds from over the nearby Sacramento urban area. Good visibilities were favored by moderate winds from rural directions. Visibilities were reduced when the wind speed became strong enough for loose materials to be picked up from the ground.
Abstract
This paper presents time cross-sections of vertical temperature structure during the 1966 Thanksgiving week air pollution episode in New York City, based on 6-hourly soundings at Kennedy Airport. The analyses depict numerous inversions in the lower 10,000 ft of the atmosphere, including an interesting sequence of surface-based inversions and an outstanding inversion aloft. Diurnal and daily variations in the height of the mixing layer can also be seen. Some possible influences of the vertical temperature structure on SO2 concentrations in Manhattan are discussed, and it is suggested that exceptional peak SO2 concentrations were largely due to the fumigation process.
Abstract
This paper presents time cross-sections of vertical temperature structure during the 1966 Thanksgiving week air pollution episode in New York City, based on 6-hourly soundings at Kennedy Airport. The analyses depict numerous inversions in the lower 10,000 ft of the atmosphere, including an interesting sequence of surface-based inversions and an outstanding inversion aloft. Diurnal and daily variations in the height of the mixing layer can also be seen. Some possible influences of the vertical temperature structure on SO2 concentrations in Manhattan are discussed, and it is suggested that exceptional peak SO2 concentrations were largely due to the fumigation process.
Abstract
Hourly surface wind-speed observations recorded over 2 yrs, at 16 Weather Bureau Airport Stations were studied to establish relationships between average daily speeds and the frequencies of individual hourly speeds. Only days with no precipitation were considered. Although the results of the study are intended for use in air pollution meteorology, they are of general interest to synoptic meteorologists.
Abstract
Hourly surface wind-speed observations recorded over 2 yrs, at 16 Weather Bureau Airport Stations were studied to establish relationships between average daily speeds and the frequencies of individual hourly speeds. Only days with no precipitation were considered. Although the results of the study are intended for use in air pollution meteorology, they are of general interest to synoptic meteorologists.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
No Abstract Available.
Abstract
Small constant-volume balloons, floating within 1700 ft. of the surface, were visually tracked over metropolitan Los Angeles by teams in automobiles. The trajectories and supporting data that were obtained are discussed, as are observing techniques and some operational difficulties.
Abstract
Small constant-volume balloons, floating within 1700 ft. of the surface, were visually tracked over metropolitan Los Angeles by teams in automobiles. The trajectories and supporting data that were obtained are discussed, as are observing techniques and some operational difficulties.
