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Indian Institute of Science Education and Research Berhampur

Earth and Environmental Sciences

EES 418 :Indian Monsoon and Its Variability  (3)

Prerequisites:EES 305, ESS 404, EES 410

Learning Objectives:

This course is designed for UG/PG students to provide a comprehensive knowledge of the Indian monsoon and its variability on different spatial and temporal time scales. The physics and dynamics of the monsoon variability involve a basic understanding of air-sea interaction, and their teleconnection with oscillations such as the El Nino-Southern Oscillation (ENSO). An in depth exploration of the background, the present understanding about nature of the system responsible for the monsoon mechanism, which leads to its variability, will be elucidated.  Skill of the state of art models in simulating and predicting the variability of the monsoon will be assessed, and problems and prospects of improvement of predictions will be considered.  In addition, the impact of the Indian monsoon on agriculture and the economy will be discussed.

Course Contents:

Unit-1: Introduction to Monsoon
Indian summer and winter monsoon, nature of winter and summer monsoon variability, present understanding of the underlying mechanisms; Interannual variability, onset over Kerala and advances, active and break spells; Convection and rainfall in the tropics - Organization over different spatial scales, conditional instability of the first and second kind; Variation of temperature, pressure and density with height in the atmosphere; Relationship between wind and pressure in rotating systems.

Unit-2: Basic System Responsible for the Monsoon
Fundamental processes in seasonal cycle; Gigantic land-sea breeze, different hypotheses for the basic system responsible for the summer monsoon; Inter Tropical Convergence Zones (ITCZs) and the Indian monsoons; Role and characteristic behavior of ITCZ during summer and winter monsoon.

Unit-3: Variation of Convection/Rainfall over the Ocean
Air-sea interaction; SST-rainfall relationship; Heat lows; ITCZ and monsoonal regions of the world; Seasonal transitions (onset and retreat) - spring to summer, advance and retreat on summer monsoon; Summer to winter transitions.

Unit-4: Intraseasonal Variation and Intraseasonal Oscillation
Active-weak spells and breaks in the monsoon.

Unit-5: El Nino and Southern Oscillation
Walker circulation, Hadley cell, Southern Oscillation index and its variability, Bjerknes theory and feedbacks; Definition of Nino regions, teleconnections, understating El-Nino, what causes El Nino and its underlying mechanism? Impact of the Asian Monsoon on ENSO.

Unit-6: Indian Ocean and the Indian Monsoon
Role of SST on monsoon; Indian Ocean Dipole (IOD) mode variability and association with winter and summer monsoon.

Unit-7: Interannual Variation of the Indian Summer Monsoon Rainfall
Links to events over the Indian and Pacific Ocean; Land surface processes; Circulation; IOD and ENSO link.

Unit-8: Monsoon Variability, Agriculture and Economy
Effect of monsoon rainfall variability (droughts and floods) on agriculture production; Relationship between variation of rice production and variation of rainfall; Agriculture production link to Gross Domestic Product.

Unit-9: Monsoon Prediction: Problems and Prospects
Short, medium and long-range monsoon prediction using statistical approach; Coupled model prediction of monsoon and their skills, and limitations in monsoon forecasting.

Suggested Readings :

  1. Fein, J. S., and Stephens, P. L., 1987, Monsoons, Wiley.
  2. Hastenrath, S., 1991, Climate Dynamics of the Tropics, Kluwer Academic Publishers.
  3. Wang, B., 2006, Asian Monsoon, Springer Praxis.
  4. Asnani, G. C., 1993, Tropical Meteorology (3 Vol. set), Asnani Publishers.
  5. Pant, G. B., and Rupa Kumar, K., 1997, Climate of South Asia, Wiley.Rao, Y. P., 1976, Southwest Monsoon. Meteorological Monograph (synoptic meteorology). No. 1, India Meteorological Department, New Delhi.
  6. Asanani, G. C., De, U. S., Hatwar, H. R., and Mazumdar, A. B., 2011, Monsoon Monograph (vol 1) India Meteorological Department, Ministry of Earth Sciences Govt. of India.

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