||Federation and Meteorology
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Meteorological Work in Australia
Meteorological Work in Australia: A Review
Map No. 1February 18th, 1890
Map No.2January 14th, 1891
Map No.3March 12th, 1891
Map No. 4, February 5th. 1890, and Map No .5, May 27th, 1893
Map No. 6, June 22nd, 1893
Map No. 7, July 14th, 1893
Map No. 7, July 14th, 1893 (continued)
Taking the five years 1888 to 1892, Mr. Russell, in a recent paper to the Royal British Meteorological Society, states that on the average about forty-three high pressure areas pass over us during the year, and that they are more frequent in summer than in winter.
Their general movement, as with cyclones, is from west to east, curving to the south-east, no doubt dying out as they reach higher latitudes. Mr. Russell makes their average rate of motion to be about 400 miles a day, passing over Australia in seven or eight days in summer and nine or ten in winter. My own observations lead me to the conclusion that anticyclonic areas seldom retain their general outlines and energy for any great length of time; both are continually varying, according to surrounding conditions. For instance, our weather charts may show an anticyclone on the west coast pushing its way inland, and in a few days covering nearly the whole of the continent; but by that time it will very frequently have greatly increased in energy, and the central pressure may be 30.5in. or more, although no such pressure may have passed over the west coast; it gets built up over the land. This is especially noticeable when there is a deep "low" adjoining, say, off the coast to the south-east, the increased pressure in the anticyclone being probably due to the upper outflow of air from the neighboring "low" or cyclone.
An anticyclone is fitful and uncertain in its movement; it may remain stationary, or nearly so, over the interior for days together, and then suddenly split up, or contract, or show diminished pressure; and then, perhaps, make a rapid forward move, and again come to a standstill, after which it will pass off to the south-east and in a few days appear over New Zealand. The movements of cyclonic areas are more marked and regular, though by no means uniform. Taking the south coastal depressions, of which about sixty pass during the year, I find they travel on the average at the rate of 25 miles an hour.
Over the United States the average is about 28.4 miles, ranging from 34.2 in February to 22.6 in August. Over the Atlantic in middle latitudes the average is 18 miles, ranging from 20 in November to 15.8 in July. Over Europe the average is 16.7, ranging from 19 in October to 14 miles in August.
The progress of our south coastal depressions is frequently retarded by anticyclonic conditions ahead or to the east of them, which will sometimes deflect them such a distance to the south as to barely affect the weather in this colony. In other cases, after pushing up into the Great Australian Bight, or near Eucla, as a well-marked V, they will, more particularly during the winter, open out and the isobars will run roughly parallel with the coast (or east and west), and we have then long shoots of north-west and west winds, with either no rain or squally showers on the Mount Lofty Ranges and the coast, and fresh westerly winds with rain through Bass's Straits. All these conditions have to be taken into account in framing our daily forecasts. Taking the last four years, the forecasts issued in South Australia have been justified to the extent of 73 per cent., partially justified 20 cent., and wholly wrong 7 per cent. In connection with this work, I have much pleasure in acknowledging the great and zealous assistance I receive from Mr. Griffiths. Our usual practice is for Mr. Griffiths and myself each to write out independently a forecast. The two are then compared, and adopted if they agree. If they disagree we discuss the conditions very carefully, and decide what the forecast shall be. In my absence this work entirely devolves on Mr. Griffiths.
People in Bright Sparcs - Russell, Henry Chamberlain; Todd, Charles
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