Table 104. 



INTERNATIONAL METEOROLOGICAL SYMBOLS. 



The International Meteorological Symbols were adopted at the Vienna meteorological con- 

 gress of 1873. A few additions and modifications have been made at subsequent international 

 meteorological meetings. The forms of these symbols are more or less flexible. Those shown in 

 the accompanying table are the forms which have generally been used in the United States, and 

 with two exceptions ("wet fog " and " zodiacal light") are identical with those used by the Prus- 

 sian Meteorological Institute and given in the German editions of the International Meteoro- 

 logical Codex. The principal variants found in the meteorological publications of the different 

 countries are given in the Monthly Weather Review (Wash., D.C.), May, 1916, p. 268. 



Exponents. — An exponent added to a symbol indicates the degree of intensity, ranging 

 from ° weak (light, etc.) to 2 strong (heavy, etc.). Thus, •°, light rain; it 2 , heavy rain. 

 German and French observers use the exponent x to denote medium intensity, in accordance 

 with the German and French versions of the report of the Vienna congress, and the German 

 editions of the Codex. The English version of the above-mentioned report and the English 

 edition of the Codex provide for the use of only two exponents, ° and 2 ; hence in English- 

 speaking countries the omission of the exponent indicates medium intensity. 



Time of occurrence. — When hours of occurrence are added to symbols, the abbrevia- 

 tion a is used for a.m., and p for p.m. Thus, • 10a — 4p denotes "rain from 10 a.m. to 

 4 p.m." 12a = noon; i2p = midnight. The abbreviation n means "during night." Stations 

 taking tri-daily observations may use a to mean between the first and second observation; 

 p, between the second and third; and n, between the third and the first. 



For further information concerning the International Symbols and other meteorological 

 symbols, see "Meteorological Symbols," by C. Fitzhugh Talman, Monthly Weather Review 

 (Wash., D.C.), May, 1016, pp. 265-274. 



Smithsonian Tables. 



232 



