Aridity index: Difference between revisions
From Glossary of Meteorology
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|Meaning= | |Meaning=#As used by C. W. Thornthwaite in his 1948 [[climatic classification]]: an index of the degree of [[water deficit]] below [[water need]] at any given station; a measure of [[aridity]]. | ||
#As used by C. W. Thornthwaite in his 1948 [[climatic classification]]: an index of the degree of [[water deficit]] below [[water need]] at any given station; a measure of [[aridity]]. | |Explanation=It is calculated, independently of the opposite [[humidity index]], as follows: <blockquote>[[File:ams2001glos-Ae27.gif|link=|center|ams2001glos-Ae27]]</blockquote> where ''d'' (the water deficit) is the sum of the monthly differences between precipitation and [[potential evapotranspiration|potential evapotranspiration]] for those months when the [[normal]] precipitation is less than the normal potential evapotranspiration; and where ''n'' is the sum of monthly values of potential evapotranspiration for the deficient months.<br/> Thornthwaite puts the aridity index to two uses: 1) as a component of the moisture index; 2) as a basis for the more detailed classification of [[moist climates]] (perhumid, humid, and moist subhumid climates).<br/> | ||
#<br/>''See'' [[index of aridity]]. | #<br/>''See'' [[index of aridity]]. | ||
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Latest revision as of 21:34, 13 January 2024
#As used by C. W. Thornthwaite in his 1948 climatic classification: an index of the degree of water deficit below water need at any given station; a measure of aridity.
It is calculated, independently of the opposite humidity index, as follows:
Thornthwaite puts the aridity index to two uses: 1) as a component of the moisture index; 2) as a basis for the more detailed classification of moist climates (perhumid, humid, and moist subhumid climates).
where d (the water deficit) is the sum of the monthly differences between precipitation and potential evapotranspiration for those months when the normal precipitation is less than the normal potential evapotranspiration; and where n is the sum of monthly values of potential evapotranspiration for the deficient months.
Thornthwaite puts the aridity index to two uses: 1) as a component of the moisture index; 2) as a basis for the more detailed classification of moist climates (perhumid, humid, and moist subhumid climates).
See index of aridity.
