Hydro-Climate Course March 2004, CU, Boulder Asian Monsoon… K. Krishna Kumar CIRES Visiting Fellow

Hydro-Climate Course March 2004, CU, Boulder Outline Monsoon MonsoonMechanisms Scales of Variability MONSOON-ENSO links and some plausible explanations of recent weakening MONSOON-ENSO links and some plausible explanations of recent weakening Empirical/Dynamical Prediction of Monsoon Rainfall Empirical/Dynamical Prediction of Monsoon Rainfall

Hydro-Climate Course March 2004, CU, Boulder Monsoons The term ‘MONSOON’ is derived from the Arabic word ‘mausim’, which means season.. Since early times, the term monsoon has been used to signify any annual climate cycle with a dominant seasonal wind reversal. Ramage’s (1971) criteria to delineate the monsoon areas of the world: Prevailing wind direction shifts by at least 120º between Jan and July Prevailing wind direction shifts by at least 120º between Jan and July Average frequency of prevailing wind direction in Jan and July exceeds 40% Average frequency of prevailing wind direction in Jan and July exceeds 40% Mean resultant wind in at least one of the months exceeds 3 m/s Mean resultant wind in at least one of the months exceeds 3 m/s

Hydro-Climate Course March 2004, CU, Boulder Global Monsoons (after C.S. Ramage, 1971)

Hydro-Climate Course March 2004, CU, Boulder Schematic of Winter (NE) and Summer (SW) Monsoons over Asia

Hydro-Climate Course March 2004, CU, Boulder Sea Level Pressure and Wind Distribution during January and July in the Tropics

Hydro-Climate Course March 2004, CU, Boulder Migration of Tropical Rain belts from Austral Summer to Boreal Summer

Hydro-Climate Course March 2004, CU, Boulder Monsoon – A Gigantic Land-Sea Breeze

Hydro-Climate Course March 2004, CU, Boulder

Role of Mountains and the Orography on Monsoons

Hydro-Climate Course March 2004, CU, Boulder Indian Summer Monsoon Flow

Hydro-Climate Course March 2004, CU, Boulder Impact of Mountain Uplift on Asian Monsoon: 850 hPa Winds (Kitoh Feb, J. Climate)

Hydro-Climate Course March 2004, CU, Boulder Impact on Rainfall Distribution

Hydro-Climate Course March 2004, CU, Boulder Impact of Mountains on the Northward propagation of Rainfall in East Asia and the very existence of Baiu Rainfall in Japan

Hydro-Climate Course March 2004, CU, Boulder Impact of Mountain Uplift on the formation of Warm Pool in the west Pacific and the east Indian Oceans

Hydro-Climate Course March 2004, CU, Boulder Indian Summer Monsoon

Hydro-Climate Course March 2004, CU, Boulder Semi-Permanent Systems of Indian Monsoon

Hydro-Climate Course March 2004, CU, Boulder Dates of Normal Onset and Withdrawal of Monson Rains in India Onset Withdrawal

Hydro-Climate Course March 2004, CU, Boulder Mean Rainfall Patterns Data Source: CMAP ( ) Summer Monsoon (mm/season) Annual (mm/year)

Hydro-Climate Course March 2004, CU, Boulder Indian Summer Monsoon Contribution to Annual Rainfall and its Variability Data Source : CMAP ( ) Monsoon/Annual (%) Coefficient of Variation (%)

Hydro-Climate Course March 2004, CU, Boulder Mean Annual Cycle of All-India Mean Monthly Rainfall

Hydro-Climate Course March 2004, CU, Boulder Monsoon Variability IntraseasonalInterannualDecadal/CenturyMillennia & longer Onset/withdrawal; Active and break- monsoon phases; day oscillations; severe rainstorms Droughts and floods Changes in the frequency of droughts and floods Changes in the areal extents of monsoons Atmospheric variability; tropical- midlatitude interactions; Soil moisture; Sea surface temperatures Atmospheric interactions; El Niño/ Southern Oscillation; Top layers of tropical oceans; Snow cover; Land surface characteristics Monsoon circulation variations; Deep ocean changes; Greenhouse gases increase; Human activities; Biospheric changes; Volcanic dust Global climate excursions; Ice ages; Warm epochs; Sun-earth geometry Factors Features

Hydro-Climate Course March 2004, CU, Boulder Intra-seasonal Oscillations: Active/Break Cycles Madden-Julian (30-60 day) Oscillations

Hydro-Climate Course March 2004, CU, Boulder Daily Evolution of Rainfall on all-India Scale

Hydro-Climate Course March 2004, CU, Boulder OLR Anomalies Associated with prolonged break situations in the Indian region

Hydro-Climate Course March 2004, CU, Boulder Madden-Julian Oscillations:

Hydro-Climate Course March 2004, CU, Boulder Eastward Propagating Tropical OLR Anomalies (MJO)

Hydro-Climate Course March 2004, CU, Boulder Northward Propagation of Cloud bands in the Indian region known as day Oscillations

Hydro-Climate Course March 2004, CU, Boulder Madden-Julian Oscillations:

Hydro-Climate Course March 2004, CU, Boulder Interannual Variability of Indian Monsoon Rainfall and Links with El Niño – Southern Oscillation

Hydro-Climate Course March 2004, CU, Boulder The Stability of the Indian Summer Monsoon

Hydro-Climate Course March 2004, CU, Boulder

Quasi-Biennial Cycle in Monsoon Rainfall Cycles/year Biennial cycle in monsoon rainfall is attributed to the response of land-sea to strong/weak monsoons Stronger monsoon leading to the cooling of the Indian land-mass And the adjoining seas resulting in a weaker land-sea gradient in the Next year and a weaker monsoon (refer to Gerry Meehl’s work for further understanding)

Hydro-Climate Course March 2004, CU, Boulder MonRF epochs

Hydro-Climate Course March 2004, CU, Boulder

Schematic view of sea surface temperature and tropical rainfall in the the equatorial Pacific Ocean during normal, El Niño, and La Niña conditions....

Hydro-Climate Course March 2004, CU, Boulder Global Impacts of ENSO

Hydro-Climate Course March 2004, CU, Boulder Low-frequency co-variability of Monsoon Rainfall and ENSO

Hydro-Climate Course March 2004, CU, Boulder

Difference in the Composites of Winter (Prior to Monsoon) Surface Air Temperatures over the Eurasian Region during El Nino Events pre and post-1980 periods ( ) – ( ) El Ninos Diff. Climatologies of these Periods

Hydro-Climate Course March 2004, CU, Boulder Relation between Indian Monsoon Rainfall and  200 (A,B) and the Composites of  200 for El Nino Events pre-,post-80’s (C,D)

Hydro-Climate Course March 2004, CU, Boulder Sea Surface Temp Anomalies in 1982 & 1997 JJA 82 SON 82 JJA 97 SON 97 Monsoon Rainfall: -13% Monsoon Rainfall: +2%

Hydro-Climate Course March 2004, CU, Boulder Sea Surface Temp Anomalies: 1987 & 2002 JJA 87 SON 87 JJA 02 SON 02 Monsoon Rainfall: -18% Monsoon Rainfall: -19%

Hydro-Climate Course March 2004, CU, Boulder Precipitation Anomalies: JJA Monsoon Rainfall: -13% Monsoon Rainfall: +2% Monsoon Rainfall: -18% Monsoon Rainfall: -19%

Hydro-Climate Course March 2004, CU, Boulder Precipitation Anomaly in NE Australia (DJF) and NE Brazil (JFM) in 1988 and

Hydro-Climate Course March 2004, CU, Boulder Surface Temp Anomaly over North America: DJF

Hydro-Climate Course March 2004, CU, Boulder Precipitation/ Forecasts of SST and Precipitation in JAS 2002 by Different GCMs

Hydro-Climate Course March 2004, CU, Boulder

SST Patterns Used for ENSO Experiments

Hydro-Climate Course March 2004, CU, Boulder SST Patterns Used for Indian Ocean Experiments

Hydro-Climate Course March 2004, CU, Boulder A A C

Response of Indian Monsoon Rainfall to Different El Nino Related SST Patterns ModelMonsoonRainfall ENSO - CTL NINODL-NINOENSOGW-ENSO

Hydro-Climate Course March 2004, CU, Boulder

Bibliography on Monsoon Research