Dependence of Snowfall on Temperature
D'OOGE has reported1 a correlation between amount of snowfall in inches and temperature at the time of snowfall. His data showed that maximum depth of snowfall occurred at a daily mean temperature of − 11° C. ; Bossolasco2 correlated frequency of occurrence of snowfall with temperature and found maximum occurrence at approximately the same temperature. These observers assumed that the mean daily temperature recorded at the level of observation was a reasonable estimate of the temperature at the level of formation of the snow. From the data presented, conclusions were drawn concerning nucleation of snow crystals.
Snowfall and Temperature on a California Mountain
A SNOWFALL and temperature analysis has been completed for six winter seasons (1948–54) on White Mountain, California (elevation 10,600 ft.). Snowfall and the temperature maxima and minima were measured for every 24 hr. at 0800 Pacific Standard Time. Fig. 1a shows the total snowfall as a function of the mean air temperature of the day on which the snow fell. An interesting peak occurs at − 11 ° C., just as Bossolasco reports1 for the case of snowfall at Weissfluhjoch. Rau's laboratory work2 indicates that the majority of atmospheric nuclei induce freezing between − 10° and − 12° C. Silver iodide begins its activity as a freezing nucleus in the laboratory at − 4° C. 3, and at this point Fig.1a shows another peak. Bossolasco has also mentioned that Mason and Ludlam4 report this point as a secondary maximum in laboratory frequency of atmospheric freezing nuclei. However, it is believed that the − 4° C. peak may be related to large cloud-seeding experiments utilizing silver iodide smoke carried on in the Sierra Nevada Mountains about thirty miles up wind to the west5 during the seasons 1951, 1952 and 1953. Vonnegut6 expected that unusual and far-reaching effects must be expected in the case of such seedings, since silver iodide is much more active than any known natural ice nucleus.
Die Populationsdynamik Von Canthocampt Us Staphylinus (Jurine) (Copepoda, Harpacticoida) Im Litoral Des Bodensees
The population dynamics of Canthocamptus staphylinus in the littoral zone of Lake Constance are described (fig. 2). Adult animals aestivate as cysts. The main part of the population emerges from the cysts in autumn. During the resting stage and the first spell after emerging, mortality is very low (fig. 3). Reproduction, expressed as numbers of ovigerous females, begins in November and reaches its maximum in January. The new generation becomes adult in May/June and encysts without previous reproduction. According to Sarvala (1979) it may be possible, that in littoral populations dormancy is induced by long day periods and temperatures of over 12° C (figs. 1, 2). In the profundal zone C. staphylinus also forms cysts, however, both light and temperature are not likely to induce this stage in depths of over 60 m.