Extrapolation of Solar Radiation Measurements: Mesoscale Analyses from Arizona and Tennessee Valley Authority Regions

Abstract

Relationships for determining the maximum permissible distance for extrapolating daily totals of solar radiation from measurement sites are established for mesoscale monitoring networks in southern Arizona and the Tennessee Valley Authority (TVA) region. The method involves calculation of the standard deviation of the daily differences in solar radiation receipt for pairs of measurement stations in order to determine a coefficient of variability. This is then plotted as a function of distance between station pairs to establish an extrapolation distance relationship. Results indicate that the solar climate of southern Arizona has much greater spatial coherence than that for the TVA region, thus permitting extrapolation of data over longer distances. However. extrapolation distances for daily totals of solar radiation are very small in either study area. Applied to monthly totals for an error tolerance of ±10% at a 90% confidence level. permissible extrapolation distances of more than 400 km for southern Arizona and ?200 km for the Tennessee Valley were found. However, the extrapolation distances may vary with season.