\begin{table}%t1
  \caption{\label{tabWarren07}Mean cloud properties obtained from surface and satellite measurements.}
  %\centerline
{\begin{tabular}{l r r r r r r}
    \hline\hline
    \noalign{\smallskip}
     & \multicolumn{3}{c}{Cloud coverage (\%)\tablefootmark{a}} & \multicolumn{3}{c}{Global average cloud properties\tablefootmark{b}}\\
    Cloud type & Ocean & Land & Global mean & Top temperature & Top pressure & Optical depth\tablefootmark{c}\\
    \noalign{\smallskip}
    \hline
    \noalign{\smallskip}
    \textbf{Low-level clouds} & 47 & 22 & 39.5 & $281.1 \ {\rm K}$ & $0.826 \ {\rm bar}$ & 4.7\\
    Stratus & 12 & 5 & 9.9 & & &\\
    Stratocumulus & 22 & 12 & 19.0 & & &\\
    Cumulus & 13 & 5 & 10.6 & & &\\
    Cumulonimbus\tablefootmark{d} & 6 & 4 & 5.4 & & &\\
    \noalign{\smallskip}
    \textbf{High-level clouds} & 12 & 22 & 15.0 & $227.5 \ {\rm K}$ & $0.267 \ {\rm bar}$ & 2.2\\
    Cirriform & 12 & 22 & 15.0 & & &\\
    \noalign{\smallskip}
    \hline
  \end{tabular}}
\par
    \tablefoot{\tablefoottext{a} {Taken from surface observations \citep{Warren07}, the global mean coverages have been derived by a weighted average from the coverages over ocean ($70\%$) and land ($30\%$).}
    \tablefoottext{b} {From satellite observations within the ISCCP (see \citealt{Rossow99a}, for details).}
    \tablefoottext{c} {Optical depth at $0.6 ~ {\rm \mu m}$.}
    \tablefoottext{d} {Not included in the model and in the calculation of the mean coverages.}}
\end{table}