## 2 Clouds Properties from Infrared and Microwave Satellite Observations
### Infrared Observations Only
A new version of the Pathfinder ATMOSpheres extended (PATMOS-x) multidecadal Cloud Properties Climate Data Record (CDR) is available from NOAA National Centers for Environmental Information (NCEI). Ref. [102] presents the new features introduced which concern the introduction of the HIRS 7.3- and 13.3-um bands, the update of the previous values for the naive Bayesian detection scheme, and the improvement of cloud detection. The effects of these changes result in greater consistency in cloud-top height and phase distribution, as well as in polar cloud detection, when compared to MODIS EOS. Table 2 summarizes the main information for each study reviewed in Section 2.2, the sensors and channels used, and the products investigated. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Satellite**} & \\ \cline{3-5}
**Authors** & **Year** & \multicolumn{1}{c}{**Sensor**} & \multicolumn{1}{c}{**Channel Frequency**} & \multicolumn{1}{c}{**Main features**} & \multicolumn{1}{c}{**Uncertainty or Accuracy**} \\  & & & **Sensor** & **Frequency** & **and the Method (When** & **Declared/Applicable)** \\ \[PERSON] [PERSON] and & & & & & \\ [PERSON] [34] & 1962 & - & - & Cloud properties & - \\ Smith and Platt [35] & 1978 & - & - & Cloud properties & - \\ [PERSON] et al. [36] & 1983 & - & - & Cloud properties & - \\ Eyre and Menzel & & & & Cloud & \\ [PERSON] and Menzel [37] & 1989 & - & - & microphysics & - \\  & & & & (i.e., particle size, & \\  & & & & & COT) & \\ [PERSON] et al. [38] & 1990 & - & - & Cloud & \\  & & & & & \\  & & & & & \\ [PERSON] et al. [39] & 1993 & - & - & microphysics & \\  & & & & (i.e., particle size, & \\  & & & & & COT) & \\ [PERSON] and & & & & (i.e., particle size, & \\ [PERSON] [40] & 1990 & - & 2.16, 3.7 & COT, R\({}_{\rm eff}\) & - \\ [PERSON] and & 1995 & AVHRR & 3.75, 11 & COT, R\({}_{\rm eff}\) & RMSE\({}_{\rm COT,Ref,\%}\) \(<\) 25\% \\ [PERSON] [42] & 1995 & AVHRR & 3.75, 11 & COT, R\({}_{\rm eff}\) & RMSE\({}_{\rm COT,Ref,\%}\) \(<\) 25\% \\ [PERSON] et al. [45] & 1994 & AVHRR & - & Cloud particle radii & - \\ [PERSON] and Feijt [46] & 2005 & AVHRR & 1.6 & CLWP & RMSE\({}_{\rm CLWP}\) = 28 g/m\({}^{2}\) \\ [PERSON] et al. [48] & 2000 & AVHRR & 1.6 & CLWP & - \\ [PERSON] et al. [49] & 2003 & AVHRR & 1.6 & Cloud properties & RMSE\({}_{\rm CDNC}\) = 48.4 cm\({}^{-3}\) \\ [PERSON] et al. [50] & 2004 & AVHRR & 1.62, 2.13 & COT, R\({}_{\rm eff}\), cloud phase & - \\ [PERSON] et al. [51] & 2001 & - & - & Cloud & - \\ [PERSON] et al. [52] & 2006 & AVHRR, SEVIRI & 1.6, 3.8 & COT, CLWP, CPP & - \\ [PERSON] et al. [53] & 2009 & MODIS & - & R\({}_{\rm eff}\), COT, CT & - \\ [PERSON] et al. [54] & 2016 & MODIS & 8.6, 10.4, 11.2, & CTH, COT, R\({}_{\rm eff}\), & RMSE\({}_{\%}\)\(<\) 30\% \\ [PERSON] et al. [54] & 2016 & MODIS & 12.4 & CTP & RMSE\({}_{\%}\)\(<\) 30\% \\ [PERSON] et al. [55] & 2018 & AHI & - & CTH, COT, R\({}_{\rm eff}\), & - \\  & & & & CTP & \\ [PERSON] et al. [56] & 1972 & IR sounder & - & microphysical & - \\  & & & & properties & \\  & & & & Cloud radiative & \\ [PERSON] et al. [57] & 1993 & IR sounder & - & and & \\  & & & & microphysical & - \\ [PERSON] et al. [58] & 2003 & IR sounder & - & Cloud properties & - \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Infrared observations-only recap table.