Spectrum of solar irradiance at top of Earth's atmosphere.

• Neither Sun nor Earth are black bodies; both have significant absorption by certain gases in their atmospheres, which produce absorption lines in their electromagnetic spectra, which is the distribution of energy as a function of wavelength, or wavenumber.

• Wavenumber is the number of waves per unit length, the inverse of wavelength, and is usually given in inverse centimeters, or cm^-1, with 5,000 cm^-1 corresponding to a wavelength of 2 millionths of a meter, or 2 microns. Taking inverses, 10000 cm^-1 is 1 micron, 20000 cm^-1 is 0.5 microns, and so on to larger wavenumbers, and similarly 2000 cm^-1 is 5 microns, 1000 cm^-1 is 10 microns, and so on to smaller wavenumbers.

• The distribution of energy versus wavenumber is the spectrum.

The best current estimate of the spectrum of solar irradiance at the top of the atmosphere is based on line-by-line computations by Bob Kurucz of Harvard Smithsonian Observatory. Units are watts per square meter per inverse centimeters per steradian, and the original data has been degraded to 20 cm^-1 resolution.

The red line gives the best post-1992 solar spectum estimate, and the dark line shows the best previous estimate of the spectrum. Note the marked improvement provided by the more recent higher spectral resolution line-by-line computations. (Note that if plotted directly in wavelength, the peak would be at 0.5 microns, but a change of variables to wavenumber shifts the peak to 10000 cm^-1 = 1 micron.) Common absorption lines are identified, including doubly-ionized calcium and the first four lines of the hydrogen Balmer series.

	本文件完全由NASA创作，在美国属于公有领域。根据NASA的版权方针，NASA的材料除非另有声明否则不受版权保护。（参见Template:PD-USGov/zh、NASA版权方针页面或JPL图片使用方针。）
	警告: 使用NASA的标志、徽章、徽标等受到美国法律14 CFR 1221的限制。 NASA网站大量存储来自苏联或俄罗斯航天机构的图片，以及其他非美国的航天机构图片。这些文件不一定属于公有领域。 根据哈勃空间望远镜的数据制作的材料，如果不是明确声明由STScI提供，则可能受到版权保护。[1]参见{{PD-Hubble}}和{{Cc-Hubble}}。 SOHO（ESA和NASA）联合项目表示，由旗下的探测器创作的材料受版权保护，且对于商业性非教育目使用材料需要授权。[2] 每日一天文图（APOD）网站上展示的图片可能受到版权保护。[3] 国家太空科学数据中心（NSSDC）网站据信存储了受版权保护内容。其图库常见问答表明除非另有声明，图库的所有图片都属于公有领域。

Source: http://climate.gsfc.nasa.gov/~cahalan/Radiation/SolarIrr.html

Author: Robert Cahalan

(Moved from en:Image:Solar_irradiance_spectrum_1992.gif)

此graph图片可使用矢量图形重新创建为SVG文件。这具有很多好处；更多信息请参见共享资源:待清理媒体。如果存在此图片的SVG格式，请将其上传，然后将此模板替换为{{vector version available|新图片名称}}。 建议您将SVG命名为“Solar irradiance spectrum 1992.svg”，这样在使用Vector version available（或Vva）模板时就不需要填写新图片名称参数。