Mesoscale Convective Systems Observed by CloudSat Robert A. Houze, PI Study 1: Jasmine Cetrone Study 2: Jian Yuan CloudSat Science Team Meeting, Seattle, 20 August 2008

Goal: Structure and composition of MCS Anvils AC AS

Study 1: Identify MCSs by tracking West Africa Maritime Continent Bay of Bengal

Find MCS Anvils Find potential MCS signal in CPR data Track cloud systems in geostationary satellite data to decide if MCS Tb<208K over 100-km scale at some point in its lifetime Find anvil portion of CPR signal Non-precipitating anvil if less than -10 dBZ at all levels below 5 km

Analysis of Anvils Number of cases: Anvils stratified by thickness 82 over West Africa 78 over the Maritime Continent 42 over the Bay of Bengal Anvils stratified by thickness Thin (0-2 km), Medium (2-6 km) and Thick (>6 km) Plotted CFADs

All Anvil CFADs Thin, medium, thick combined Diagonal mode West Africa Thin, medium, thick combined Diagonal mode Not as high over West Africa Even though convection more intense TRMM shows rain echoes higher! Large ice particles? Mar. Cont. Bay Bengal

Thick Anvil Results West Africa thick anvils High reflectivity peak ~8 km another indication of larger ice Bimodal structure at low-reflectivity values Confirmed by ARM ground-based cloud radars Lower maximum may be a result aggregation Mar. Cont. Bay Bengal

ARM Thick Anvil Results Niamey Darwin

Study 2: Objective Identification of MCSs Rain Rate: AMSR-E Aqua L2B Global Swath Rain Rate (AE_Rain). Horizontal Cloud Structure: MODIS MODIS/Aqua Clouds 1km and 5km 5-Min L2 Wide Swath Subset along CloudSat V2 at GES DISC(GES_DISC_MAC06S1_v2) Vertical Cloud Structure: CloudSat Products 2B-GEOPROF; 2B-CWC-RO; 2B-FLXHR; …

Identification of High Cloud Features MODIS Tb11 (K) AMSR/E Rain (mm/h) COMBINED Cloud Element Rain Core FEATURE MASK

Further Analysis Identify MCSs: Stratify MCSs Rain area 2,000-40,000 km2 Mean Tb11 <235 K Rain area with R>10 mm/hr > 200km2 Stratify MCSs Cold: Tb11_min<208 K Warm: 208 Ko<Tb11_min<220 K Subdivide Cold and Warm by size

Global-seasonal distribution of MCS Largest 20 % of “Cold” MCSs (>14,000 km2) Latitude Nº 50% of cold MCS precip

Combined Analysis (CPR data in MCSs) CFAD of thick and Thin Anvils of Cold MCS The color map shows the fraction (number of occurrence at each height-reflectivity bin normalized by the total number of valid sample at 11 km).

Combined Analysis Thickness-Distance Distribution for Anvils of Cold MCSs West Pacific (100-160 E)

Conclusions & Future Work Temporally tracked MCSs Used manual tracking to identify MCSs CFADs suggest larger ice particles over Africa Thick anvils show a bimodal signature at low reflectivity confirmed by ARM cloud radars Objective identification of MCSs Used MODIS and AMSR E to identify MCSs Reasonable global patterns of MCS types Vertical structure agrees with manually tracked MCSs Next work Statistics of structure, composition, and radiative heating in MCS anvils

Thank You

Thank You

Study 2: Data AMSR-E/Aqua L2B Global Swath Rain Rate (AE_Rain). MODIS/Aqua Clouds 1km and 5km 5-Min L2 Wide Swath Subset along CloudSat V2 at GES DISC(GES_DISC_MAC06S1_v2) CloudSat products (2B-GEOPROF;2B- CWC-RO; 2B-FLXHR…)

Global-seasonal distribution of MCS Smallest 40 % of “Cold” MCSs (2000-4900 km2) Latitude Nº 15% of precip in cold MCS category

Vertical Structure Categories From CloudSat 54 % 9 % 3% 5% 7% 45% Overlapping within each type of cloud has been considered. Overlapping between different types are not taken into account.

Methodology Build the data base of deep cloud system (precipitating and non precipitating) basd on AMSR-E rain rate and MODIS Tb11. Group deep cloud systems into different categories based on their properties(size of the raining area, coldest Tb11, intense raining area etc. Co-locate CloudSat data with the cloud database and determine their parenting MCSs. Composite cloud structures according to their parenting MCSs.

High Cloud System identification Co-location of different datasets 'Nearest neighbor' matching, convert AE-Rain to MODIS resolution Picking high cloud systems Determining high cloud boundary based on Tb11 gradients and rain fall pattern Determining cloud cores (raining or non-raining cold cores) in multi-core systems

MCS Definition MCS1:Size>2000km2; Tb11_min<208Ko; Tb11_mean<235Ko; area with R>10mm/hr bigger than 200km2 MCS2:Size>2000km2,208Ko<Tb11_min<228Ko, Tb11_mean<235Ko; area with R>10mm/hr bigger than 200km2

Global-seasonal distribution of MCS Large “Warm” MCSs (10000-21360km2)

Thick Anvil Results Bimodal structure at low-reflectivity values West Africa Bimodal structure at low-reflectivity values Confirmed by ARM ground-based cloud radars Lower maximum may be a result aggregation West Africa thick anvils Reach lower heights than other regions despite having tallest precipitation echoes High reflectivity peak ~8 km may indicate larger ice Mar. Cont. Bay Bengal