Langley (unit) explained

langley
Standard:	Non-SI metric unit
Quantity:	Heat flux
Symbol:	Ly
Namedafter:	Samuel Langley
Extralabel:	Derivation
Extradata:	1 calth/cm^2
Units1:	SI units
Inunits1:	41 840 J/m^2

The langley (Ly) is a unit of heat transmission, especially used to express the rate of solar radiation (or insolation) received by the earth. The unit was proposed by Franz Linke in 1942^[1] and named after Samuel Langley (1834–1906) in 1947.

Definition

One langley is

• 1 thermochemical calorie per square centimetre,^[2]
• 41 840 J/m² (joules per square metre)^[3]

See also

• Solar constant
• Radiant exposure

Notes and References

1. Encyclopedia: Gyllenbok. Jan. Jan Gyllenbok. Encyclopaedia of Historical Metrology, Weights, and Measures, Volume 1. langley. 2018. Birkhäuser. 9783319575988. 139.
2. Web site: A. Thompson and B. N. Taylor. Appendix B9. Conversion Factors.. NIST Guide to the SI. The National Institute of Standards and Technology. 2010-10-05. 2013-04-14.
3. Web site: Solar Energy at Race Rocks. 2010-08-05. https://web.archive.org/web/20131005002713/http://www.racerocks.com/racerock/abiotic/solar/solar.htm. 2013-10-05. dead.