Creating a Climatology of Shortwave Radiation in the Northeastern United States

Utility-scale solar power plants are greatly impacted when incoming shortwave radiation is less than expected in a region. This is due to unanticipated weather patterns over long time periods. However, cloud cover and radiation are typically estimated for a site based on persistence forecasts, which use data that are often only available for a decade.  Because of the short-term availability of these data, it is difficult to study the historical climatology of shortwave radiation, thus making future projections uncertain.  Another readily available climate variable is diurnal temperature range, which has been shown to correlate well with daily averaged shortwave radiation values in some regions.  In the present study, the diurnal temperature range is shown to be an excellent predictor of shortwave radiation in the Northeastern United States and can thus serve as a proxy for shortwave radiation throughout the period of record. The dependence of this correlation on the season, elevation, latitude, and vicinity to large bodies of water is examined.  Calculated shortwave radiation can provide information about recent variability and trends, while also providing data necessary for climate model validation.