1. Extreme Convection in the Equatorial Zone as Seen by 16 Years of TRMM PR
M. D. Zuluaga and R. A. Houze, Jr.
University of Washington
PMM Science Team Meeting, Baltimore, 7 August 2014

2. Use TRMM to find the most pronounced convective & stratiform elements
Identify every contiguous 3D echo object (“storm”) seen by PR
Convective component
Stratiform component
Extreme characteristic
Contiguous 3D volume of convective echo > 40 dBZ
Top height > 10 km
“Deep convective core”
Horizontal area > km2
“Wide convective core”
Contiguous stratiform echo with horizontal area > km2
“Broad stratiform region”

4. Diurnal Behavior in Each Subregion

5. DCC
WCC
BSR
Land
Coastal
Open ocean

6. Synoptic Scale Environments
(ERA-I)

7. Africa
700 hPa anomaly fields:
Geopotential height
Wind vectors

8. Coast of Tropical America
850 hPa anomalies

9. Orographic Enhancement over Andes
Anomalies of divergence and specific humidity
Andes
Div.
Orographic Enhancement over Andes

10. East Pacific ITCZ

11. Storms with BSR associated with Tropical Cyclone (TC) development in the East Pacific
Tropical disturbance trajectory*
Storms with BSR
Storms with BSR associated to a TCs
*database: Northeast and North Central Pacific hurricane best-track data (HURDAT2, NHC)
~30% of storms

12. Summary: Behavior of extreme convective metrics in the near equatorial region
Diurnal Strongest for DCCs over land Sequence consistent with upscale growth: DCCWCCBSR
Orographic
Powerful enhancement of WCC & BSR by flow over Andes
Synoptic
Prominent for mesoscale organized features: WCC & BSR
Maxima of WCC and BSR associated with lows at hPa
BSR over oceans max in regions of TC genesis

13. End
This research was supported by: NASA grants NNX13AG71G, NNX12AJ82G, NNX10AH70G DOE grant DE-SC NSF grants AGS , AGS and AGS

14. ITCZ intersects two landmasses of differing characteristics

15. DCC
BSR
WCC

16. Summary: Behavior of extreme convective metrics in the near equatorial region
DCCs mark the early stage of MCS 40 dBZ over land, 30 dBZ over ocean strongly diurnally forced—especially over mountains
WCCs aggregated intense convection—in maturing MCSs occur over both land and sea occur later in day than DCC associated with 700 hPa synoptic-scale cyclonic flow enhanced by orographic lifting
BSRs occur in late stages of MCSs mostly oceanic—near west coasts diurnal variability is slight but max later than WCC associated with TC development over oceans west of Africa and SA

17. Association of echo types with convection metrics
Deep & Wide
Deep conv.
Wide conv.
Broad Str.