A Decade of the Moderate Resolution Imaging Spectroradiometer: Is a Solar–Cloud Link Detectable?

Abstract

ased on the results of decadal correlation studies between the International Satellite Cloud Climatology Project?detected cloud anomalies and the galactic cosmic ray (GCR) flux, it has been suggested that a relationship exists between solar activity and cloud cover. If valid, such a relationship could have important implications for scientists? understanding of recent climate change. In this work, an analysis of the first decade of Moderate Resolution Imaging Spectroradiometer (MODIS)?detected cloud anomalies are presented, and the data at global and local geographical resolutions to total solar irradiance (TSI), GCR variations, and the multivariate El Niño?Southern Oscillation index are compared. The study identifies no statistically significant correlations between cloud anomalies and TSI/GCR variations, and concludes that solar-related variability is not a primary driver of monthly to annual MODIS cloud variability. The authors observe a net increase in cloud detected by MODIS over the past decade of ~0.58%, arising from a combination of a reduction in high- to midlevel cloud (?0.31%) and an increase in low-level cloud (0.89%); these long-term changes may be largely attributed to ENSO-induced cloud variability.