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- Author or Editor: DWIGHT B. KLINE x
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Abstract
Concentrations of ice nuclei detected with refrigerated devices vary with observational techniques and may be influenced by small differences in the thermal compatibility of otherwise similar instruments. To provide improved homogeneity in the observations obtained for this investigation, all mechanically identical equipment was calibrated against a “reference” instrument. The median concentration levels of the standardized measurements at 15 observational sites spanned approximately 2 orders of magnitude at −20°C. Data obtained at the 11,150-ft. elevation of Mauna Loa Observatory, Hawaii, clearly revealed low values compared with all other locations. It may be inferred from this evidence that terrestrial aerosols contribute dominantly to the ice nuclei budget of the lower atmosphere, at least as detected by the expansion method under conditions surveyed in the United States.
Abstract
Concentrations of ice nuclei detected with refrigerated devices vary with observational techniques and may be influenced by small differences in the thermal compatibility of otherwise similar instruments. To provide improved homogeneity in the observations obtained for this investigation, all mechanically identical equipment was calibrated against a “reference” instrument. The median concentration levels of the standardized measurements at 15 observational sites spanned approximately 2 orders of magnitude at −20°C. Data obtained at the 11,150-ft. elevation of Mauna Loa Observatory, Hawaii, clearly revealed low values compared with all other locations. It may be inferred from this evidence that terrestrial aerosols contribute dominantly to the ice nuclei budget of the lower atmosphere, at least as detected by the expansion method under conditions surveyed in the United States.
Abstract
A series of ice nucleus measurements at Mauna Loa Observatory obtained concurrently with Millipore filter samples which were subjected to chemical analyses for chloride particles are briefly described. These aerosol concentrations displayed a pronounced relationship with flow regimes at the Observatory. The results emphasize the need for care in collecting data at this unique site to insure against contamination from low-level sources. Both aerosols increased up to nearly three orders of magnitude during sustained diurnal upslope flow conditions. The depiction of chloride particle counts with distance from the shoreline of the Island of Hawaii was in general agreement with similar data obtained in the Puerto Rican environment.
Abstract
A series of ice nucleus measurements at Mauna Loa Observatory obtained concurrently with Millipore filter samples which were subjected to chemical analyses for chloride particles are briefly described. These aerosol concentrations displayed a pronounced relationship with flow regimes at the Observatory. The results emphasize the need for care in collecting data at this unique site to insure against contamination from low-level sources. Both aerosols increased up to nearly three orders of magnitude during sustained diurnal upslope flow conditions. The depiction of chloride particle counts with distance from the shoreline of the Island of Hawaii was in general agreement with similar data obtained in the Puerto Rican environment.
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.
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.
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.
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.
