## 4 Potential Instrument, Suitable Platforms, and Technological Limitations
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Technology Type** & **Measurements** & **Instrument Limitations** & \multicolumn{2}{c}{**Instruments Identified**} \\ \hline  & & & \multicolumn{1}{c}{} & TM[25] & SSM/1[4] \\ \cline{4-5} Microwave Radiometer Imager & Wind speed over sea surface & & & \multicolumn{1}{c}{} & Available commercial platform (Non-exclusive) \\ (K. K., K.-Wbands) or & Sea ice cover & & \multicolumn{1}{c}{} & resolution and \\ (K., K.-W-bands) & Sea ice type & & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\ (K., K.-W-bands) & Sea ice drift & & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\ \cline{4-5}  & Sea surface temperature (at X-band) & & \multicolumn{1}{c}{} & \multicolumn{1}{c}{} \\ \cline{4-5}  & & & \multicolumn{1}{c}{} & TEM-XL [1] \\ \hline  & Surface soil moisture & & \multicolumn{1}{c}{} & \\  & Sea ice cover & & \multicolumn{1}{c}{} & \\  & Crop growth \& condition & \multicolumn{1}{c}{} & \\  & Sea ice thickness & & \multicolumn{1}{c}{} & \\ \cline{4-5} Microwave Radiometer Imager & & & \multicolumn{1}{c}{} & \\ (L-band) & Sea ice thickness & & \multicolumn{1}{c}{} & \\ \cline{4-5}  & Sea ice thickness & & \multicolumn{1}{c}{} & \\ \cline{4-5}  & & & \multicolumn{1}{c}{} & \\ \hline  & & & \multicolumn{1}{c}{} & \\  & & & \multicolumn{1}{c}{} & \\ \cline{4-5}  & & & \multicolumn{1}{c}{}  
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**Technology Type** & **Measurements** & **Instrument Limitations** & **Instruments Identified** \\ \hline \multirow{8}{*}{Receiver: AIS} & & & SD ALS Receiver [58] & NAIS [57] \\ \cline{3-4}  & & & **Available commercial platform (Non-exclusive)** \\ \cline{3-4}  & & & **COMPX2U/3U** [88] & COMK 3U [88] \\ \cline{3-4}  & & & THUNDE (BU), GKP/PHON (GNB) [85] & SMAL SAT 6U [12] \\ \cline{3-4}  & & & Endezvous [31] & MAI3000 [17] \\ \cline{3-4}  & & & SMALSAT 6U [12] & Endezvous [30] \\ \hline \multirow{8}{*}{Multispectral radiometer (VIS/MWIR/TR)} & & & \\  & Ocean chlorophyll concentration & Cloud sensitivity & \\  & Ocean imagery and water leavin radiance & Day light only & AVIRR\(/3\)[25] & VIRS [25] \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \cline{3-4}  & & & \\ \hline \multirow{8}{*}{Hyperspectral radiometer (VIS/NIR)} & & & **Available commercial platform (Non-exclusive)** \\ \cline{3-4}  & & & **SSTL-X30 [91]** & SN-S0 [21] \\ \cline{3-4}  & & & **S**S**S0 [21] & Altair [20] \\ \cline{3-4}  & & & **Day light only** & Altair [20] \\ \cline{3-4}  & & & & \\ \hline \multirow{8}{*}{Hyperspectral radiometer (VIS/NIR)} & & & CHRS [25] & COMS [25] \\ \cline{3-4}  & & & **Available commercial platform (Non-exclusive)** \\ \cline{3-4}  & & & **LEG**S0-30 [109] & **MAI3000 [23]** \\ \cline{3-4}  & & & **SN-S0 [12]** & NEMO [15] \\ \cline{3-4}  & & & **SN-S0**S [90] & LEGS-30 [95] \\ \cline{3-4}  & & & **MEI2** [20] & DEFAIN [58] \\ \cline{3-4}  & & & **S**S**S0 [21] & SMAL SAT 12U [12] \\ \hline \multirow{8}{*}{Hyperspectral sounder (IR)} & & & **CON-IR-25]** & CrS [25] \\ \cline{3-4}  & & &