Multi-sensor Analysis of Tropical Mesoscale Convective Systems Jian Yuan and R. A. Houze [J. Clim., J. Atmos. Sci.] NASA A-Train Symposium, New Orleans, 27 October 2010

Example of mesoscale convective systems “MCSs” Large areas of cold top

1458GMT 13 May 2004 Convective Precipitation Stratiform Precipitation Radar Echoes in the 3 MCSs Large rain areas

Non-precipitating “anvil clouds” of MCSs have not been studied very much Extensively studied Need to understand how anvil is related to the raining region Mesoscale Convective System

A-Train instruments make it possible to observe both raining and anvil components

123 Three steps of analysis of multi-sensor data (TB11) (GEOPROF-2B) (RAIN)

MODIS TB11 + AMSR-E combined to find“cold centers” & “raining areas” Use 260 K threshold Locate 1 st closed contour Use 1 mm/h threshold for rain rate Associate pixels with nearest cold center Use 6 mm/h threshold for heavy rain

Define criteria for MCS that are reasonable for all these regions

MCS Criteria Systems whose raining cores have Area > 2000 km 2 Min TB11 ≤ 220 PDF of rain amount as a function of raining core properties Size of raining core Min TB11 over raining core Must have one dominant core with intense cells, and accounting for >70% rain area  56% all tropical rain 2000 km °C

MCSs Over the Whole Tropics Smallest 25% (<12,000 km 2 ) Largest 25% (>40,000 km 2 ) “Superclusters”

MODIS/AMSR-E  identifies MCSs  separates out the anvil component CloudSat  structure of the anvils

Frequency of MCS anvils over tropics

Bulk Properties of MCS anvils identified by 3 A-Train instruments bulk width & thickness seen by CloudSat

Africa Indian Ocean Height (km) Internal MCS anvil structure seen by CloudSat

Anvil structure shown by CloudSat Width and depth differs between land and ocean Reflectivity distribution suggests larger particles dominate at lower levels & smaller aloft Reflectivity distribution weakens with distance from rain more quickly over land Anvil structure far from raining cores similar everywhere Anvil structure close to raining cores differs land to ocean

Conclusions COMBINING 3 A-TRAIN INSTRUMENTS Identifies MCS Separates them into raining and anvil components Allows anvils to be analyzed relative to raining component LEADS TO UNPRECEDENTED ANALYSES OF MCSs Global MCS climatology obtained Different categories of MCSs identified Anvil width, depth, and interior structure quantified Differences between land and ocean anvils identified

End This research was supported by NASA grants NNX07AQ89G and NNX10AM28G