The book is the first to focus on the physical oceanography of the North Indian Ocean (NIO), a special region of the global ocean that exhibits a distinct seasonality due to the impact of the South Asian Monsoon (SAM). It is written as a textbook about the NIO for graduate students, lecturers, and researchers in physical oceanography. It will also be useful for courses on the interior, coastal, and equatorial dynamics in any other ocean. It helps readers, particularly new entrants to the field, to gain a comprehensive understanding of tropical-ocean dynamics by: developing from first principles the equation set for the linear continuously stratified (LCS) model, which has long been used to study tropical oceans; and then obtaining solutions that explore different aspects of the dynamics.
Part 1 of the book provides an overview of observed ocean circulations and forcing functions in the NIO that are linked to the SAM. Part 2 develops the equations of motion for the LCS model. Part 3 (Free Waves) and Part 4 (Forced Solutions) derive and discuss analytic solutions to the LCS model that illustrate basic processes in the interior (unbounded), coastal, and equatorial regions of the ocean. The last two chapters of Part 4 consider more complicated processes and phenomena that build upon the simpler solutions previously found: vertical propagation of coastal and equatorial waves, and the Indian Ocean's shallow overturning circulations. Each analytic solution is illustrated (and extended) by a suite of numerical LCS solutions presented as video clips, providing a powerful means for visualizing complex processes.
Author(s): Julian P. McCreary, Satish R. Shetye
Series: Atmosphere, Earth, Ocean & Space
Publisher: Springer
Year: 2023
Language: English
Pages: 522
City: Cham
Preface
Contents
1 Introduction
1.1 Observational Background
1.2 Theoretical Background
1.3 Book Overview
Part I Observations: Atmospheric Forcing and Ocean Response
2 Atmospheric Circulation
2.1 Monsoons and the ITCZ
2.1.1 General Properties
2.1.2 South Asian ITCZ
2.2 South-Asian Summer Monsoon
2.2.1 Precipitation and Orography
2.2.2 Monsoon Winds
2.2.3 SST and Ocean Processes
2.2.4 Non-orographic Rainfall
2.2.5 Summary
2.3 Interannual Variability
2.3.1 ENSO
2.3.2 IOD
2.4 Sub-annual Variability
2.4.1 Madden-Julian Oscillations
2.4.2 Quasi-biweekly Mode
2.4.3 Sub-weekly Oscillations
2.4.4 Diurnal Variability
3 Ocean Forcing and the Surface Mixed Layer
3.1 Ocean Forcing
3.1.1 Definitions
3.1.2 Climatological Fluxes
3.2 Surface Mixed Layer
3.2.1 Mixed-layer Processes
3.2.2 Mixed-layer Models
3.2.3 Basin-wide Properties
3.2.4 Arabian Sea and Bay of Bengal
4 Ocean Circulations
4.1 Thermohaline Structure
4.1.1 Overview
4.1.2 Bottom Layer
4.1.3 Deep Layer
4.1.4 Intermediate Layer
4.1.5 Upper Layer
4.2 Climatological Surface Currents and Sea Level
4.2.1 Currents
4.2.2 Sea Level and Geostrophic Velocity
4.3 Southern-Hemisphere Circulations
4.3.1 South Equatorial Thermocline Ridge
4.3.2 South Equatorial Current
4.3.3 South Equatorial Countercurrent
4.3.4 East Africa Coastal Current
4.4 Equatorial Region
4.4.1 Wyrtki Jets
4.4.2 Upwelling Events
4.4.3 Equatorial Undercurrents and Deeper Flows
4.4.4 Intraseasonal Oscillations
4.5 Sumatra/Java Coast
4.5.1 Mean Currents
4.5.2 Semiannual and Annual Cycles
4.5.3 Intraseasonal Variability
4.5.4 Dynamics
4.6 Andaman Sea
4.6.1 Background Properties
4.6.2 Annual Cycle
4.6.3 Intraseasonal Variability
4.6.4 Dynamics
4.7 Bay of Bengal
4.7.1 Interior Circulation
4.7.2 Intraseasonal Variability and Eddies
4.7.3 East India Coastal Current
4.7.4 Western-Boundary Gyres
4.7.5 Salt Balance
4.8 Monsoon Currents
4.8.1 Summer Monsoon Current
4.8.2 Winter Monsoon Current
4.8.3 Dynamics
4.9 Arabian Sea
4.9.1 Lakshadweep High and Low
4.9.2 West India Coastal Current
4.9.3 Pakistan Coastal Current
4.9.4 Interior Circulation
4.9.5 East Arabia Coastal Current
4.9.6 Somali Current
4.9.7 Salt Balance
4.10 Marginal Seas
4.10.1 Persian Gulf
4.10.2 Gulf of Oman
4.10.3 Red Sea
4.10.4 Gulf of Aden
Part II Models
5 Ocean Models
5.1 Ocean General Circulation Models
5.1.1 Equations
5.1.2 Mixing
5.1.3 Boundary Conditions
5.1.4 Coordinate Systems
5.2 Linear, Continuously Stratified Model
5.2.1 Equations of Motion
5.2.2 Boundary Conditions
5.2.3 Vertical Normal Modes
5.2.4 Barotropic and Baroclinic Modes
5.2.5 Modal Equations
5.2.6 Convergence
5.3 Layer Models
5.3.1 Overview
5.3.2 Nonlinear 112-layer Model
5.3.3 Linear 112-layer Model
5.3.4 Multi-layer Models
5.4 Potential Vorticity
Part III Free Waves
6 Overview
6.1 Wave Structure
6.1.1 Plane Wave
6.1.2 General Wave
6.1.3 Other Waves
6.2 Dispersion Relation
6.3 Wave Groups in a Uniform Medium
6.4 Impact of a Slowly-varying Medium
6.5 Impact of Mixing
7 Midlatitude Waves
7.1 Gravity and Rossby Waves
7.1.1 Dispersion Relation
7.1.2 Phase and Group Velocities
7.1.3 Extension to Variable f
7.1.4 Critical Latitudes
7.1.5 Videos
7.2 Kelvin Waves
7.2.1 Zonal Coasts
7.2.2 Meridional Coasts
7.3 Boundary-Generated Rossby Waves
7.3.1 Solution
7.3.2 Videos
7.3.3 Meridional Energy Propagation
7.4 Waves Along a Slanted Coast
7.4.1 Kelvin Waves
7.4.2 Rossby-Wave Pathways
7.5 Observations
7.5.1 Critical Latitude
7.5.2 Meridional Energy Propagation
7.5.3 Zero-Group-Velocity Resonance
8 Equatorial Waves
8.1 Hermite Functions
8.2 Equatorial Gravity and Rossby Waves
8.2.1 Dispersion Relation
8.2.2 Phase and Group Velocities
8.2.3 Videos
8.3 Mixed Rossby-Gravity Wave
8.4 Equatorial Kelvin Wave
8.5 Relationship to Midlatitude Waves
8.6 Observations
Part IV Forced Solutions
9 Overview
9.1 Common Aspects
9.1.1 Approximations
9.1.2 Basin and Boundary Conditions
9.1.3 Radiation and Initial Conditions
9.1.4 Wind-stress Forcing
9.2 Dirac δ-function
9.3 Transform Methods
9.3.1 Fourier Transforms
9.3.2 Laplace Transforms
9.4 Examples
9.4.1 Switched-on Forcing
9.4.2 Periodic Forcing
10 Ekman Drift and Inertial Oscillations
10.1 Midlatitude Ocean
10.1.1 Constant f
10.1.2 Variable f
10.1.3 Observations
10.2 Equatorial Ocean
10.2.1 Single-mode Response
10.2.2 Solutions with z-dependence
10.2.3 Observations
10.3 Review
11 Sverdrup Flow and Boundary Currents
11.1 Interior Circulation
11.1.1 Solution
11.1.2 Videos
11.1.3 Pycnocline Response
11.1.4 Observations
11.2 Boundary Currents
11.2.1 Western Boundary
11.2.2 Other Boundaries
11.2.3 Observations
12 Interior Ocean
12.1 Simplified Model Equations
12.2 Constant-f Solutions
12.2.1 Switched-On Forcing
12.2.2 Periodic Forcing
12.2.3 Observations
12.3 Variable-f Solutions
12.3.1 Switched-On Forcing
12.3.2 Periodic Forcing
12.3.3 Observations
13 Coastal Ocean
13.1 Simplified Model Equations
13.2 Switched-On Forcing
13.2.1 Two-Dimensional Response
13.2.2 Three-Dimensional Response, β=0
13.2.3 Three-Dimensional Response, β=0
13.3 Periodic Forcing
13.3.1 Solution
13.3.2 Dynamics
13.3.3 Videos
13.3.4 Solutions for a Slanted Boundary
13.4 Observations
13.5 River-Driven Circulations
14 Equatorial Ocean: Switched-On Forcing
14.1 Simplified Model Equations
14.2 Interior Solution
14.2.1 Small-Time Response
14.2.2 Long-Time Solution
14.3 Reflections from a Single Boundary
14.3.1 East-Coast Reflections
14.3.2 West-coast Reflections
14.4 Reflections from Both Boundaries
14.5 Observations
15 Equatorial Ocean: Periodic Forcing
15.1 Interior Solution
15.1.1 v Field
15.1.2 u Field
15.1.3 p Field
15.1.4 Dynamics
15.1.5 Videos
15.2 Reflections from a Single Boundary
15.2.1 Eastern Boundary
15.2.2 Western Boundary
15.2.3 Meridional Energy Propagation
15.2.4 Reflections from a Slanted Boundary
15.3 Observations
15.4 Equatorial Resonances
15.4.1 Equatorial Basin Resonance
15.4.2 Zero-Group-Velocity Resonance
16 Beams and Undercurrents
16.1 Beams
16.1.1 Properties
16.1.2 Videos
16.1.3 Observations
16.2 Undercurrents
16.2.1 Conceptual Explanations
16.2.2 Dynamics
16.2.3 Videos
16.2.4 Observations
17 Cross-Equatorial and Subtropical Cells
17.1 Overview
17.2 Structure
17.2.1 Two-Dimensional Overturning
17.2.2 Three-dimensional Pathways
17.2.3 Transports
17.2.4 Observations
17.3 Dynamics
17.3.1 Model Overview
17.3.2 STC Dynamics
17.3.3 CEC Dynamics
17.3.4 Cross-Equatorial Flow
17.3.5 Equatorial Roll
Appendix A List of Acronyms
Appendix B Simplified LCS Equations
B.1 Non-dimensional Parameters
B.2 Parameter Choices
B.2.1 General Scalings
B.2.2 Interior-Ocean Scaling
B.2.3 Coastal-Ocean Scaling
B.2.4 Equatorial-Ocean Scaling
Appendix C Video Overview
Appendix References
Index
