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- Author or Editor: Hans Neuberger x
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Summary
It is shown that a memory scale for determination of sky-blueness will yield accurate and comparable observations.
Summary
It is shown that a memory scale for determination of sky-blueness will yield accurate and comparable observations.
The nature of Arago's neutral point of atmospheric polarization and its underlying physical principles are explained. Various criteria of atmospheric turbidity that can be derived from observations of this neutral point are discussed and their relative merits compared. Examples of the usefulness and potentialities of these criteria are cited. In particular, the influence of the size of the particles polluting the atmosphere and of meteorological factors on spectral observations of Arago's neutral point is shown. A selection of problems connected with the interpretation of measurements of Arago's point is presented.
The nature of Arago's neutral point of atmospheric polarization and its underlying physical principles are explained. Various criteria of atmospheric turbidity that can be derived from observations of this neutral point are discussed and their relative merits compared. Examples of the usefulness and potentialities of these criteria are cited. In particular, the influence of the size of the particles polluting the atmosphere and of meteorological factors on spectral observations of Arago's neutral point is shown. A selection of problems connected with the interpretation of measurements of Arago's point is presented.
Summary
Under symmetrical light conditions the optical modification produced by a snow surface decreases the antisolar distance of Arago's neutral point. Therefore, for investigations of the atmospheric turbidity by means of observations of Arago's point this effect must be taken into consideration.
Summary
Under symmetrical light conditions the optical modification produced by a snow surface decreases the antisolar distance of Arago's neutral point. Therefore, for investigations of the atmospheric turbidity by means of observations of Arago's point this effect must be taken into consideration.
Summary
It is shown that the quantitative estimates of the apparent shape of the sky cannot be explained by the geometric and physical conditions of the atmosphere. Observations of the angular elevation of the midpoint of the arc: Horizon-Zenith, show that with increase in cloudiness the sky appears to become flatter. The effect of different cloudtypes on the apparent shape of the sky is explained by the structure of the clouds themselves. However, no significant relation between the ceiling height and sky shape was found.
Aside from the influence of the angular elevation of the terrestrial horizon, an important factor determining our impression of the shape of the sky is the distance between observer and topographic horizon as well as the contour of the foreground, as is shown by special measurements. This conclusion is confirmed by the relation between visual range and the apparent shape of sky as well as measurements through red color filter.
Summary
It is shown that the quantitative estimates of the apparent shape of the sky cannot be explained by the geometric and physical conditions of the atmosphere. Observations of the angular elevation of the midpoint of the arc: Horizon-Zenith, show that with increase in cloudiness the sky appears to become flatter. The effect of different cloudtypes on the apparent shape of the sky is explained by the structure of the clouds themselves. However, no significant relation between the ceiling height and sky shape was found.
Aside from the influence of the angular elevation of the terrestrial horizon, an important factor determining our impression of the shape of the sky is the distance between observer and topographic horizon as well as the contour of the foreground, as is shown by special measurements. This conclusion is confirmed by the relation between visual range and the apparent shape of sky as well as measurements through red color filter.
Previous, and more recent, comparisons of electronmicroscopic and conventional nuclei counts show that the Aitken counts are deficient. Special experiments revealed that the cause for this deficiency lies in the rapid decay of nuclei in the time lapse between sampling and counting nuclei. It was found that a lapse of 30 seconds reduces the nuclei concentration in the counter by roughly 50%. When this decay is considered, the Aitken and electron microscopic counts can be brought into good agreement.
Previous, and more recent, comparisons of electronmicroscopic and conventional nuclei counts show that the Aitken counts are deficient. Special experiments revealed that the cause for this deficiency lies in the rapid decay of nuclei in the time lapse between sampling and counting nuclei. It was found that a lapse of 30 seconds reduces the nuclei concentration in the counter by roughly 50%. When this decay is considered, the Aitken and electron microscopic counts can be brought into good agreement.
