Correlations In Spatial Variability When Accounting For Cloud Advection

Spatiotemporal variability of irradiance has been a topic of interest in the literature. This study attempts to separate advective and uncorrelated portions of the spatially distributed irradiance by comparing cross correlations between site pairs within an irradiance measurement network and accounting for time lag when calculating those cross correlations. Following techniques in the literature, cross correlations are computed as a function of site pair separation distance for multiple wavelet transform timescales. Results show that the well known form of the correlation's decline can be maintained by considering the lagging correlation and the component of the site pair separation distance perpendicular to the overall cloud motion. This may open the door for additional fidelity in modeling of spatiotemporal irradiance that more formally represents how the loss of correlation with distance depends on the cloud motion vector.