Comment on "Observational and model evidence for positive low-level cloud feedback".

Clement et al. (Reports, 24 July 2009, p. 460) provided observational evidence for systematic relationships between variations in marine low cloudiness and other climatic variables and found that most current-generation climate models were deficient in reproducing such relationships. Our analysis of one of these models (GFDL CM2.1), using more complete model output, indicates better agreement with observations, suggesting that more detailed analysis of climate model simulations is necessary.