Complementary use of passive and active remote sensing for detection of penetrating convection from CloudSat, CALIPSO, and Aqua MODIS

[1] The study examines penetrating deep convection (PDC), that reach ∼14 km (PDC14) and ∼17 km (PDC17), using 1 year of colocated CloudSat, CALIPSO, and Aqua-MODIS observations. The combination of multisensory and multispectral observations is used to examine how well PDC14(17) are captured using cold cloud features (CCFs), defined as groupings of 1 km MODIS pixels with ∼11μm brightness temperature (BT) less than or equal to 210 K and 235 K and positive brightness temperature differences (+BTD) between ∼6.7 μm (BT6.7) and ∼11 μm (BT11). Cross-comparison of PDC14 with CCFs ≤ 210 K and +BTD signatures according to date, time, and geolocation show that within the tropics 61% (55%) of CCFs ≤ 210 K (+BTD) occur as PDC14. In the case of CCFs ≤ 210 K, ∼27% of the PDC14 distribution also occur as cold altostratus/anvil clouds. Results show that 50–59% of PDC14 are large enough to be detected from IR observations with a horizontal resolution of 5 km. Although observations are sampled along CloudSat's narrow swath where CloudSat/CALIPSO and Aqua MODIS observations are colocated, the study provides statistical evidence supporting the use of IR observations to study the long-term temporal and spatial variability of high reaching deep convective cloud activity.