ORIGIN OF COLD WAVES OF AIR.

New Zealand Tablet, Volume III, Issue 153, 7 April 1876, Page 14

ORIGIN OF COLD WAVES OF AIR.

Dr. Klein, in reference to the use of daily weather reports, states that in Europe as in America, in all cases, the reports of the weather westward of a given station are of the greatest importance, while the reports from stations to the east are, on the average, of minor importance in making weather predictions. A southerly wind in the region of Iceland, Scotland, or Norway indicates the approaching side of an area of low barometer. It is therefore a sign ot a coming change in the weather. A northerly wind in those regions indicates, for Germany, that the pressure of the air from the ocean is high, and can be considered as a sign of steady, pleasant weather. Irregular changes of atmospheric pressure and of the winds are extremely slight in Eastern Asia, and the cold of winter, when once commenced, continues uninterruptedly in Eastern Siberia with a permanent high barometer. The reason of this is found in the existence of the great mountain chains of Asia. The region of high barometer is generally separated from oceans and from equatorial regions by these lofty chains of mountains. The coldest and densest stratum of air can, therefore, not flow away towards the sea. Its only escape is found at points like Jakutsk, where it passes over land 3,000 feet above the ocean. Thus, throughout the whole interior of Asia, the lower stratum of air remains quite cold and heavy, until the summer sun, heating the surface of the earth, stirs up the atmosphere, very much as water boils in a vessel over the fire. That which takes place in Asia is repeated in a much less intense degree in America. The area of greatest cold on this continent is not prevented by any range of mountains from extending southward and eastward, but is only hemmed in on the west by the Rocky Mountains. Thus, while the Pacific coast is protected from an overflow of very cold air, the whole eastern portion of America becomes peculiarly subject to it.