The Solis clear sky model is a spectral scheme based on radiative transfer calculations and the Lambert–Beer relation. Its broadband version is a simplified fast analytical version; it is limited to broadband aerosol optical depths at 700nm lower than 0.45, which is a weakness when applied in countries with very high turbidity such as China or India. This paper aims to extend the validity of the model to higher aerosol optical depth values. In 2014, Zhang published a modification of the scheme to extend its validity to aerosol optical depth values up to 6.5, but this extension is only applicable for the beam irradiance component and presents some weakness for very high turbidity values. In a first step, we tried to apply a correction to the Zhang adaptation. In order to extend the use of the original simplified version of Solis for high turbidity, we developed a new version of the broadband Solis, valid for the three components, global, beam and diffuse, and for the four aerosol types defined by Shettle and Fenn.