Hi Rick,

Thanks for your question.

As far as I know SRI is a number between 0 to 100.

The Solar Reflectance Index (SRI) is used to determine the effect of the reflectance and emittance on the surface temperature. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100.

I think the 0.38 is the Solar Reflectance and 0.86 is the Thermal emittance. If so then the calculated SRI will be 41 and the albedo which is same as the solar reflectance is hence 0.38.

Definitions:

Albedo or Solar reflectance is expressed either as a decimal fraction or a percentage. A value of 0 indicates that the surface absorbs all solar radiation, and a value of 1 represents total reflectivity. Generally, albedo is associated with color, with lighter colors being more reflective.

Thermal emittance is also expressed either as a decimal fraction between 0 and 1, or a percentage.

Solar Reflectance Index (SRI) is used to determine the effect of the reflectance and emittance on the surface temperature. It is defined so that a standard black (reflectance 0.05, emittance 0.90) is 0 and a standard white (reflectance 0.80, emittance 0.90) is 100.

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