Insolation assessment studies

Research in insolation assessment concentrated on broadband model development and evaluation and spectral measurements and modeling. The need for high quality data was shown by evaluation of models used to form the SOLMET and ERSATZ data bases. Comparisons of model estimates with high quality data show mean bias errors as great as 20%. Particularly, models results were poor for cloudy conditions. Advances in spectral research include development of a simple spectral model (SPECTRAL) and industry development of portable spectroradiometers. Both were used to generate spectral irradiance standards and to study the effects of clouds, air mass, and turbidity on solar cell performance.