Southern annular mode (SAM)

Santhosh Kumar 22/11/2023

Southern annular mode (SAM) mind map
Discovered by INCOIS
Role
Shaping sea conditions
Indian Ocean
Description
North-south movement
Southern westerly winds
Timescales
Decades to centuries
Defined as pressure difference
At 40°S and 65°S
Importance
Influences wave patterns
Climate driver
Affects rainfall and temperature
Swell waves specifics
Regular, longer period waves
Generated by energy beneath surface
Self-sustaining
Key regions in Indian Ocean
Extratropical southern Indian Ocean (ETSI)
Tropical southern Indian Ocean (TSIO)
Phases
Positive SAM phase
Anomalous air pressure distribution
Effects on weather and wave activity
Negative SAM phase
Pressure and wind shifts
Impact on wave heights
Significance of SAM study
Predict sea state windows
Utilization by oil and shipping industries
Aids in
Coastal planning
Resource management
Disaster preparedness

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