## 4 Discussion  
Current ADMs over cloudy scenes have been designed to change with cloud optical thickness and cloud phase. However, a sensitivity towards cloud droplet size and cloud-topped water vapor has not been considered. We show that TOA SW anisotropy changes substantially in situations deviating from median conditions (e.g., much smaller or larger effective radii than 10 um) which could ultimately lead to the introduction of regional flux biases in monthly means. We identified anisotropy driving factors which should be considered in future ADMs. We believe that observed regional differences in TOA SW fluxes are a result of a sampling bias. Such bias stems from the fact that individual samples rarely meet ADM median conditions for factors impacting anisotropy (such as cloud effective radius and cloud-topped moisture). Moreover, regional samples can deviate from the median systematically (e.g., stratocumulus clouds near continents are more likely to contain larger cloud droplet number concentrations leading to generally smaller droplet sizes). Alternatively, regional samples can have a temporally shifting deviation from median \begin{table}
\begin{tabular}{l c c c c c c} \hline  & \multicolumn{2}{c}{**SE Atlantic**} & \multicolumn{2}{c}{**NE Pacific**} & \multicolumn{2}{c}{**Southern Ocean**} \\ \hline  & **January** & **July** & **January** & **July** & **January** & **July** \\ \hline No. of footprints & 602 & 2286 & 655 & 2276 & 447 & 1004 \\ Solar Earth Angle (\(\,\)) & 26.16 (7.4–34.6) & 41.7 (34.2–49.8) & 54.8 (44.7–59.7) & 19.0 (104.2–27.9) & 44.0 (37.1–52.3) & 84.7 (57.8–6.2) \\ Cloud-top Effect Radius (μm) & 11.0 (8.2–14.1) & 8.2 (6.6–14.4) & 11.6 (8.0–17.1) & 10.4 (7.6–16.0) & 10.5 (7.2–16.2) & 12.3 (8.8–16.7) \\ Cloud-topped Water Vapor (kg m\({}^{-2}\)) & 16.15 (5.2–9.0) & 1.6 (0.0–15.2) & 0.0 (0.0–8.3) & 11.6 (9.3–2.5) & 5.9 (2.2–14.1) & 0.5 (0.0–5.9) \\ TOA SW Flux Difference (W m\({}^{-2}\)) & 1.5 (–7.3–12.3) & 0.9 (–6.4–7.9) & 2.4 (–3.3–9.9) & 0.7 (–9.6–12.8) & 1.2\({}^{\ast}\)(–6.0–7.7) & 1.1 –(3.0–10.9) \\ \hline \end{tabular}
\end{table} 
Table 4: We present median conditions (in \(\theta_{s}\), cloud-top effective radius, and cloud-topped water vapor) and median flux errors together with their 5 th and 95 th percentiles (in parenthesis) for three selected regions (SE Atlantic (20\({}^{\circ}\) S–0\({}^{\circ}\) N, 5\({}^{\circ}\) W–13\({}^{\circ}\) E), NE Pacific (15\({}^{\circ}\) N–35\({}^{\circ}\) N, 140\({}^{\circ}\) W–120\({}^{\circ}\) W), and Southern Ocean (62\({}^{\circ}\) S–50\({}^{\circ}\) S, 50\({}^{\circ}\) W–20\({}^{\circ}\) E) as shown in Figure 8) and two calendar months (January and July of 2007). Asterisks mark significant differences identified in Figure 8.  
conditions as a changing climate might produce a progressively warmer and moister atmosphere as well as additional cloud condensation nuclei. However, even for regions which meet median conditions (and show a distribution around it), compensation of flux errors (under- and overestimating equally to reach correct monthly means) cannot be guaranteed, as shown in the example \"Southern Ocean\". It is the nature of polar orbiting, such as Aqua and Terra, or geostationary satellites, such as the Meteosat series, to perceive regions such that \(\theta_{s}\) are co-occurring with certain combinations of \(\theta_{v}\) and \(\phi\). To reach a perfect compensation, one needed to capture an underestimated \(R_{e}\) (e.g., 15 um; provided that ADMs represent 10 um as median condition) where there had been an overestimation of \(R_{e}\) (e.g., 5 um) before under identical viewing and illumination geometry. Most regional flux biases were positive (up to 10 W m\({}^{-2}\)). Could stratocumulus clouds be more reflective than previously reported? Global climate models persistently produce \"too-few-too-bright\" low-level clouds [4] and show regional biases to CERES EBAF, such as the AM4.0 (atmosphere model) of about 20 W m\({}^{-2}\)[31]. Our samples represent a small portion of all low-level cases.