Erratum

Erratum for the Research Article “Aerosol-driven droplet concentrations dominate coverage and water of oceanic low-level clouds” by D. Rosenfeld, Y. Zhu, M. Wang, Y. Zheng, T. Goren, S. Yu

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Science  21 Jun 2019:
Vol. 364, Issue 6446, eaay4194
DOI: 10.1126/science.aay4194

In the Research Article “Aerosol-driven droplet concentrations dominate coverage and water of oceanic low-level clouds,” because of a programming error, the calculated cloud liquid water path (LWP) was given as the average for the whole 110 km × 110 km of the scene, and not for the cloudy area alone. Figure 3C, Fig. 4, G to I, and Fig. 6, A and B, have been corrected accordingly, as have the respective LWP statistics in Tables 1 to 3.

The corrected analysis of LWP brings down its susceptibility to cloud drop concentrations (Nd), λ = ∂ln(LWP)/∂ln(Nd), to very low positive values, which are much more in line with previous studies, as shown in the corrected Table 1.

The results, with respect to all other properties and the conceptual model illustrated in Fig. 3, are not affected. This includes the conclusion of the much greater than previously estimated susceptibility of cloud radiative effect (CRE) to Nd, to the extent that yet unknown compensating aerosol warming effects are implied. The error also did not affect in any way the finding that aerosol-driven droplet concentrations dominate the coverage of oceanic low-level clouds. The conceptual diagram (Fig. 5) is also not affected.

According to the corrected Table 1, the susceptibility of the cloud cover (Cf) to Nd explains half of the overall susceptibility of CRE to Nd. This means that aerosols induce clouds to reflect solar radiation by their effects on Cf as much as the aerosol effects on the clouds’ albedo. When adding the small indicated positive λ, aerosol effects on CRE through their effects on Cf and LWP are larger than the albedo effect. Therefore, the study still demonstrates that aerosol-driven droplet concentrations dominate CRE mainly by their effects on the coverage of oceanic low-level clouds.

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