1. MJO is: A convective disturbance that initiates over the tropical Indian Ocean and propagates eastward. MJO “wave” can propagate around the entire tropics. Has implications for: Monsoons Tropical Cyclone frequency and intensity Extratropical teleconnections MJO initiation poorly handled by global numerical models. Initiation physics not understood Madden Julian Oscillation (MJO)

2. Hypothesis Hypo. I: MJO convective envelop only develops when the moist layer is deep enough; Hypo. II: Specific convective populations at different stages are essential for MJO initiation; Hypo. III: The barrier layer, wind- and shear-driven mixing, shallow thermocline, and mixing-layer entrainment all play essential roles in MJO initiation. “Discharge-Recharge” MJO onset theory MJO Initiation and Hypothesis

3. DYNAMO field phase carried out October 2011 through February 2012 “ DYNAMO examines the role of the ocean and atmosphere in formation of the MJO. ” DYNAMICS of the MJO (DYNAMO)

4. Photo courtesy of T. Lang R/V Roger Revelle, SIO About 3 months (24/7) of Doppler radar data obtained Shipboard Operation of the NASA/TOGA Radar

5. On site: 10/02-10/29 11/09-12/04 On site: 12/18-12/31 R/V Revelle Ship Legs

6. Global MJO Phase (WH) OLR & 850 mb Winds (Nov-Dec-Jan, 1974-2009) MJO index Phase 1-8 (Wheeler and Hendon 04) 1 2 3 4 5 6 7 8 Red box (DYNAMO)

7. DYNAMO MJO Definitions Global Definition WH 04 (RMM1, RMM2) Local Definition Regional Rainfall Phase 2-3, Indian Ocean Day 0: Most active

8. MJO Phase: Global vs. Local Local index Day -15 to 15 Vs. WH MJO Phase 1-8 Consistent!

9. Atmospheric Moisture Profiles—Revelle sounding data 1. Driest Atmos: Phase 5-6 2. Lower-level Moistening: Phase 7-8 3. Upper-level Moistening: Phase 1 4. Upper Drying: Phase 4

10. Overview: Environ., Precip., and Lightning How does convective population change? Phase 1 peak lightning, peak SST, intense convection 1. In phase: RH, Rainfall, Strat. Rain. Large s/f fraction 2. In phase: SST, Lightning, CAPE.

11. Convective Feature Database (TOGA Radar) 20-dBZ radar clusters Max Height (20, 30, 40 dBZ) Conv./Strat. Info. Feature Size Info. Lightning Info. Rain Rate Info.

12. Overall Statistics of Convective Population DYNAMO vs. TRMM, and TOGA-COARE MIT data?

13. Diurnal Cycles of Convective Population DYNAMO vs. TRMM, and TOGA-COARE

14. Convective (feature) Population Small ( 1000 km 2 ) Shallow ( 8 km) “Similar Pattern in Oct and Nov. MJO Cycle”

15. Horizontal Precipitating Area

16. Areal Mean Rain Amount

17. Joint PDF of Horizontal Rain Cover (> 20dbz) High % of Stratiform Precip. Deep & Less Strat. Rain

18. CFADs of Radar Pixels Mean (a) & Difference from mean (b)-(i) Solid lines: Mean Color: positive difference

19. Typical Case in Phase 1 to 4 P 1 P 2 P 3 P 4

20. Typical Case in Phase 5 to 8 P 5-6 P 7 P 8

21. Daily Evolution: Convective Population 1. In phase: RH, Rainrate, Strat. Rain. 2. In phase: SST, Lightning, CAPE. Role of Aerosols?

22. Daily Evolution: Echotop Heights