A New Version of the SUNY Satellite-to-Irradiance Model – Description & Validation

July 28, 2015
Session T1B: Solar Resource: Models and Calibration — Room 105
8:30 am  -  9:30 am

“The initial version of the SUNY satellite-to-irradiance model was introduced in 2002 based upon the underlying fundamental work of Schmetz, Canot et al., and Zelenka et al. This model falls in the category of semi-empirical models whereby a physical radiative transfer model is empirically modulated by a satellite-derived cloud index. Version 2 of the model was introduced in 2004 to overcome issues associated with solar-position-dependent ground reflectivity in the southwestern US causing the high ground albedo to be misinterpreted as clouds depending on time of day. This second version was used to produce the National Solar Resource Data Bases (NSRDB) and became the engine of SolarAnywhere. The model was continuously improved over the years and geographical resolution was enhanced to the native satellite’s resolution of ~ 1 km. The introduction of satellite IR sensors to improve performance during ground snow cover conditions led to Version 3 as the current engine of SolarAnywhere.

This article presents and validates Version 4 of the SUNY model. This new version introduces three new modeling elements:

1. An improved source of aerosol optical depth (AOD) for a better representation of the clear sky radiative transfer model background.
2. The ingestion of short term forecasts (nowcasts) driven in part by numerical weather prediction (NWP) models.
3. A new (empirical) treatment of the model’s dynamic range to better reflect observations made during very clear and highly overcast conditions.

The new version results in substantial performance improvement across a diversity of climates in North America.

Schmetz, J. (1989): Towards a Surface Radiation Climatology: Retrieval of Downward Irradiances from Satellites. Atmos Res., 23, pp. 287-321
Cano, D., J.M. Monget, M. Aubuisson, H. Guillard, N. Regas and L. Wald, (1986): A Method for the Determination of Global Solar Radiation from Meteorological Satellite Data. Solar Energy 37, pp. 31-39
Zelenka, A., Perez R, Seals R. and Renné D., (1999): Effective Accuracy of Satellite-derived irradiance, Theoretical and Applied Climatology, 62, 199-207
Perez R., P. Ineichen, K. Moore, M. Kmiecik, C. Chain, R. George and F. Vignola, (2002): A New Operational Satellite-to-Irradiance Model. Solar Energy 73, 5, pp. 307-317.
Perez R., P. Ineichen, M. Kmiecik, K. Moore, R. George and D. Renné, (2004): Producing satellite-derived irradiances in complex arid terrain. Solar Energy 77, 4, 363-370
Perez R., S. Kivalov, A. Zelenka, J. Schlemmer and K. Hemker Jr., (2010):.Improving The Performance of Satellite-to-Irradiance Models using the Satellite’s Infrared Sensors. Proc., ASES Annual Conference, Phoenix, Arizona”