92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Thursday, 26 January 2012: 2:15 PM
Complementary Use of CloudSat and Aqua-MODIS for Detection of Penetrating Deep Convection in the Tropical Tropopause Layer
Room 257 (New Orleans Convention Center )
Alisa Young, NOAA/NESDIS/NCDC, Asheville, NC

Penetrating deep convection, defined as deep convection with radar-lidar cloud top heights ³ 14 km, are sampled from CloudSat 2B-GEOPROF and 2B-Lidar GEOPROF products. The CloudSat normalized frequency distribution of penetrating deep convection show higher densities in the Indian and west tropical Pacific Oceans and over the equatorial continents of South and Central America and Africa. CloudSat observations of penetrating deep convection are combined with collocated Aqua MODIS observations to evaluate traditional infrared approaches used to detect deep convection that reach and penetrate through the tropical tropopause layer to ~ 14 km. Traditional IR approaches include cold cloud features (CCFs) defined as 3 km x 3 km subsets of MODIS observations with BT11 £ 210 K and positive brightness temperature differences (+BTD) between ~6.7 m and ~11 m. The study finds that from 20N-20S ~66% of CCFs £ 210 K are associated with penetrating deep convective clouds while 55% of +BTD signatures are associated with penetrating deep convective clouds. Additional analysis of optical depth for all CCFs £ 210 K from the Aqua MODIS Level 2 Cloud Product show that CCFs £ 210 K are predominantly associated with the most optically thick deep convective clouds that are characteristic of deep convective cores. This evidence suggests that cloud brightness temperatures £ 210 K are highly useful approach for sampling penetrating deep convection and may be highly useful for the long term analysis of penetrating deep convective clouds for climate studies.

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