Solar Spectral Irradiance: AM0, AM1.5G, AM1.5D

The American Society for Testing and Materials developed and defined the solar constant 1366.1 W/m2 u (also known as the total sky irradiance) and reference spectrum ASRM E490. This AM0 solar spectral irradiance is based on data from satellites, space shuttle missions, high-altitude aircraft, rocket soundings, ground-based solar telescopes, and modeled spectral irradiance.

The reference spectrum ASRM E173 AM1.5G and AM1.5D provides terrestrial uses in simulating and evaluating photovoltaic device.

The International Electrotechnical Commission (IEC)’s IEC60904-3, a terrestrial standard testing condition of the spectral distribution of the irradiance of AM1.5G, is also frequently used in photovoltaic device measurements.

ASTM E173 and IEC60904-3 AM1.5G reference spectrums are very similar. The difference in total irradiance is 4/10,000. These two are almost identical.

IEC 60904-3 is more common in measurements for terrestrial photovoltaic devices and related realm.

AM1.5G Irradiance is 1000 W/m² which equals to 100 mW/cm².

▲AM Irradiance and International Standards.