Tropical Climate Dynamics

MET 706: Tropical Climate Dynamics and Modeling Spring 2011 HIG311 (1:30-3:45pm, Tu & Th)

Instructor: Tim Li, Professor of Meteorology, POST 409B, Phone: 956-9427

I. Course objective: The objective of Met 706 is two folds. First, it provides an overview of current progress in tropical climate dynamics with a particular focus on physical mechanisms and atmosphere-ocean interactions. Second, it introduces basic numerical techniques for graduate students to construct and run simple and intermediate tropical atmospheric and oceanic models (such as the Gill model and the Cane-Zebiak type ocean model).

II. Prerequisites: MET 600, or consent of instructor.

III. Course outline:

1. Simple dynamic frameworks for the tropical atmosphere and ocean a. Equatorial wave dynamics b. Gill model c. Lindzen-Nigam model d. Cane-Zebiak model e. A 2.5-layer tropical atmospheric model f. A 2.5-layer tropical oceanic model

2. Climate mean state: ITCZ asymmetry a. Observations b. Theories Meridional wind-ocean upwelling-SST feedback Wind-evaporation-SST feedback Stratus cloud-radiation-SST feedback c. Coupled model simulations d. Mechanism for the annual cycle of eastern equatorial Pacific SST and wind e. Regulation of maximum SST

3. Tropical intraseasonal oscillation (ISO) a. Observations b. MJO theories and planetary zonal scale selection c. Northward propagation d. Effect of the vertical shear on tropical waves f. Role of air-sea interactions g. Ocean response to atmospheric ISO forcing h. Interannual variations

4. Tropical synoptic-scale variability a. Synoptic wave train in WNP: observation and theory b. Tropical cyclone genesis c. Dynamics of easterly waves d. Interactions with ISO e. Change of tropical cyclones under global warming

5. Dynamics of ENSO and the Indian Ocean dipole a. Observations b. Theories c. Cause of ENSO and IOD amplitude asymmetry d. Interaction between higher-frequency variability and ENSO e. Asymmetry of western North Pacific (WNP) circulation anomalies associated with El Nino and La Nina

6. Monsoon and the tropospheric biennial oscillation (TBO) a. Quasi-biennial and low-frequency variability of the Indian monsoon b. East Asian monsoon: Pacific-East Asia teleconnection c. TBO theories d. Air-sea coupling in the warm oceans e. Relative role of local and remote SST forcing in causing WNP monsoon variability

IV. Grade Attendance: 50% Class involvement: 20% 40-min class presentation: 30%