Comparison of cloud top heights derived from MISR stereo and MODIS CO₂-slicing

The EOS-TERRA MODIS and MISR instruments provide radiances for independent spectral and stereo retrievals of cloud top height (CTH), respectively. Collocated and coincident CTH retrievals were compared against each other and with coincident millimeter-wavelength cloud radar (MMCR) retrievals over the British Isles and the ARM SGP site. This inter-comparison suggests close agreement between MMCR, MODIS and MISR when they detect the same CTHs. When MISR detected high clouds, MISR stereo CTH was generally higher than MODIS CO2-slicing CTH. However, for large areas in most of the 27 scenes studied here, high clouds were detected by MODIS but not by MISR. These high clouds occured during periods of multi-layered clouds. Inspection of all off-nadir MISR radiances during these periods indicated that MISR has sufficient sensitivity to detect these clouds, but not with the innermost 3 MISR cameras used for stereo CTH retrieval.