CHAPTER IV

INVESTIGATING THE UPPER AIR

_Balloon Soundings into the Stratosphere._--It was the writer’s privilege to be present when some highly interesting and instructive experiments made by the Weather Bureau in coöperation with the Smithsonian Institution, in sounding the upper air were made at Avalon, Santa Catalina Island, off the coast of southern California in July and August, 1913.[J] The results of this work were in close agreement with similar soundings of the upper air throughout other surveyed portions of the earth’s atmosphere, and a record ascension for this country was made on July 30--32,643 meters or 20½ miles. In common with other observations of temperatures in the stratosphere, the minimum temperature of these soundings (-90 F., August 3) was registered within the first 10 miles.[K]

[J] University of California Chronicle, 1915, 17:1–25, Berkeley.

[K] Monthly Weather Review, 1914, 42:410, Washington.

Of especial interest to the aviator is the table on the next page which shows wind velocities increasing with elevation as determined by observations of the Avalon balloons.

RECORD OF AVALON ASCENTS, JULY-AUGUST, 1913

_Table showing Theodolite observations of wind velocities (meters per second) at elevations of 1,000 and 5,000 meters_

======+=======+=======+=======+=======+=======+======+======+======+==== |Meters |Meters |Meters |Meters |Meters |Meters|Meters|Meters| | per | per | per | per | per | per | per | per | Meters|second |second |second |second |second |second|second|second|Mean |5 p.m. |5 p.m. |10 a.m.|10 a.m.|10 a.m.|5 p.m.|4 p.m.|5 p.m.| |July 24|July 27|July 31|Aug. 1 |Aug. 2 |Aug. 3|Aug. 7|Aug. 8| ------+-------+-------+-------+-------+-------+------+------+------+---- 1,000 | 2.5 | 1.0 | 5.6 | 6.6 | 2.3 | 5.8 | 7.1 | 1.9 | 4.1 1,500 | 6.2 | 0.8 | 6.2 | 8.1 | 3.3 | 5.0 | 6.4 | 1.5 | 4.7 2,000 | 8.0 | 1.2 | 5.8 | 7.0 | 4.1 | 4.5 | 6.5 | 6.0 | 5.4 2,500 | 10.0 | 1.8 | 10.8 | 5.7 | 5.2 | 4.2 | 4.7 | 3.6 | 5.8 3,000 | 12.0 | 2.3 | 9.4 | 6.1 | 7.2 | 5.2 | 3.5 | 4.1 | 6.2 3,500 | 12.8 | 2.5 | 8.0 | 6.7 | 7.4 | 6.1 | 4.6 | 4.6 | 6.6 4,000 | 13.6 | 3.8 | 11.2 | 7.4 | 9.2 | 5.2 | 6.4 | 3.2 | 7.5 4,500 | 14.3 | 5.2 | 14.6 | 8.5 | 11.2 | 1.8 | 7.8 | 3.0 | 8.3 5,000 | 21.2 | 6.2 | 12.8 | 10.3 | 10.4 | 2.3 | | 3.4 | 9.5 ------+-------+-------+-------+-------+-------+------+------+------+----

_Charts Showing Upper-air Weather Conditions._--It is believed that the following charts when examined in connection with the accompanying explanation in the text will give the reader something of an outline as to the conditions existing in the upper regions of the atmosphere.

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Transcriber’s note:

Punctuation and spelling were made consistent when a predominant preference was found in this book; otherwise they were not changed.

Simple typographical errors were corrected.

Ambiguous hyphens at the ends of lines were retained; occurrences of inconsistent hyphenation have not been changed.