Development of Climate Change Development of Climate Change Scenarios of Rainfall and Scenarios of Rainfall and Temperature over the Indian Temperature over the Indian regionregion

Potential Impacts:Potential Impacts:

• Water ResourcesWater Resources• AgricultureAgriculture• Sea Level RiseSea Level Rise

and many more sectors…and many more sectors…

Interlinking of Rivers in IndiaInterlinking of Rivers in India

Proposed River LinkagesProposed River Linkages

Climate Scenarios:Climate Scenarios:What are they ?What are they ?

A climate scenario is a plausible A climate scenario is a plausible representation of future climate that representation of future climate that has been constructed for explicit use has been constructed for explicit use in investigating the potential impacts in investigating the potential impacts of anthropogenic climate change.of anthropogenic climate change.

Uncertainties in Climate Uncertainties in Climate ScenariosScenarios

• Specifying alternative emissions futuresSpecifying alternative emissions futures• Uncertainties in converting emissions to Uncertainties in converting emissions to

concentrationsconcentrations• Uncertainties in converting concentrations to Uncertainties in converting concentrations to

radiative forcingradiative forcing• Uncertainties in modelling the climate response Uncertainties in modelling the climate response

to a given radiative forcingto a given radiative forcing• Uncertainties in converting model response into Uncertainties in converting model response into

inputs for impact studiesinputs for impact studies

Climate SystemClimate System

Climate ModelsClimate Models

• Simplified mathematical representation of the Earth’s climate system

• Skill depends on the level of our understanding of the physical, geophysical, chemical and biological processes that govern the climate system

• Substantial improvements over the last two decades• Sub-models : atmosphere, ocean, land surface, cryosphere,

biosphere• Typical Resolution of global models (atmosphere) :

Horizontal - 250 km; Vertical 1 km• Small-scale processes : Parameterisation• Coupled models (e.g., atmosphere-ocean)• Sensitivity studies/Future projections• Internal variability/Ensemble runs

Development of Future Development of Future Scenarios of Rainfall & Scenarios of Rainfall & Temperature over IndiaTemperature over India

• IS92a (8 Coupled Atmos.-Ocean GCMs)IS92a (8 Coupled Atmos.-Ocean GCMs)• SRES A2 (5 AOGCMs)SRES A2 (5 AOGCMs)• SRES B2 (5 AOGCMs)SRES B2 (5 AOGCMs)

Simulations are generally available for about 200 Simulations are generally available for about 200 years (~1870s till 2100)years (~1870s till 2100)

A1: A world of rapid economic growth and rapid introductions of new and more efficient technologies

A2: A very heterogeneous world with an emphasis on family values and local traditions

B1: A world of ‘dematerialization’ and introduction of clean technologies

B2: A world with an emphasis on local solutions to economic and environmental sustainability

IPCC 2001 climate change scenarios

5 state-of-the-art climate models rununtil 2100 with various emission scenarios

Predicted precipitation change 2080-2000

Source: IPCC 2001 Cubasch

AOGCM simulations used from IPCC-DDCAOGCM simulations used from IPCC-DDC

Using greenhouse gas forced (following IS92A, SRES (A2/B2) scenarios) simulations of 8 different coupled ocean-atmosphere general circulation models, the rainfall and temperature scenarios for 2021-40; 2041-60; 2061-80; 2081-2100 compared to the baseline period of 1961-90 are generated for the Indian region. The models used are:

1. Canadian Center for Climate modeling (CCC) model.2. Center for Climate Research studies (CCSR) model.3. Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) model.4. Deutsches Klima Rechen Zentrum (DKRZ) model. 5. Geophysical Fluid Dynamics Laboratory (GFDL) model.6. Hadley Centered model.(HadCM3)7. Max-planck Institute(MPI) model. 8. National Center for Atmospheric Research (NCAR) model.

Global Summer (JJAS) Precipitation Patterns Global Summer (JJAS) Precipitation Patterns simulated by 8 coupled AOGCMssimulated by 8 coupled AOGCMs

Indian Summer Monsoon Patterns as simulated by 8 Indian Summer Monsoon Patterns as simulated by 8 coupled AOGCMscoupled AOGCMs

Annual Surface Air Temperature Patterns over India Annual Surface Air Temperature Patterns over India simulated by 8 coupled AOGCMssimulated by 8 coupled AOGCMs

Climate Change Scenarios of Rainfall over the Climate Change Scenarios of Rainfall over the Indian Region in 8 Coupled ModelsIndian Region in 8 Coupled Models

Climate Change Scenarios of Surface Temperature Climate Change Scenarios of Surface Temperature over the Indian Region in 8 Coupled Modelsover the Indian Region in 8 Coupled Models

Monsoon Monsoon Precipitation Precipitation

Change Change (% of 2041-60 as (% of 2041-60 as

compared to 1961-compared to 1961-90 period) due to 90 period) due to

GHG IncreaseGHG Increase

Monsoon Monsoon Precipitation Precipitation

Change Change (% of 2061-80 as (% of 2061-80 as

compared to compared to 1961-90 period) 1961-90 period)

due to GHG due to GHG IncreaseIncrease

Annual Surface Annual Surface Temperature Temperature Change (Deg. C Change (Deg. C in 2061-80 in 2061-80 compared to compared to 1961-90 1961-90 period) due to period) due to GHG IncreaseGHG Increase

Future Change in Monsoon Rainfall Variability Future Change in Monsoon Rainfall Variability (IS92a)(IS92a)

Future Change in Monsoon Rainfall Variability Future Change in Monsoon Rainfall Variability

(SRES/A2)(SRES/A2)

High-resolution Climate High-resolution Climate Change Scenarios using Change Scenarios using Regional Climate Model Regional Climate Model

(HadRM3)(HadRM3)

The Hadley Centre Regional Climate The Hadley Centre Regional Climate ModelsModels(HadRM2/HadRM3)(HadRM2/HadRM3)

• High-resolution limited area model driven at its lateral and High-resolution limited area model driven at its lateral and sea-surface boundaries by output from HadCMsea-surface boundaries by output from HadCM

• Formulation identical to HadAMFormulation identical to HadAM• Grid : 0.44° x 0.44°Grid : 0.44° x 0.44°• One-way nestingOne-way nesting• Joint Indo-UK Collaborative research programme on climate Joint Indo-UK Collaborative research programme on climate

change impacts in Indiachange impacts in India• Climate change simulations performed by the Hadley Climate change simulations performed by the Hadley

Centre using HadRM2 for the Indian region (the output is Centre using HadRM2 for the Indian region (the output is being currently analysed by IITM)being currently analysed by IITM)

• HadRM3 installed at IITM; Climate change simulations and HadRM3 installed at IITM; Climate change simulations and scenario development in progress at IITMscenario development in progress at IITM

Model OrographiesModel Orographiesin GCM and RCMin GCM and RCM

Observed and Simulated Indian Summer Observed and Simulated Indian Summer Monsoon Rainfall (GCM vs. RCM)Monsoon Rainfall (GCM vs. RCM)

Observed and Simulated (GCM and RCM) Surface Observed and Simulated (GCM and RCM) Surface Air Temperature over IndiaAir Temperature over India

Indian Indian Summer Summer Monsoon Monsoon Simulations Simulations by HadRM2by HadRM2

Indian Annual Indian Annual Surface Surface Temperature Temperature Simulations by Simulations by HadRM2HadRM2

Simulation of Monsoon Simulation of Monsoon Depressions/Cyclonic Storms in Depressions/Cyclonic Storms in HadRM2 and Likely Future HadRM2 and Likely Future ChangesChanges

• Changes in Monsoon Changes in Monsoon Depression/Cyclonic Storm Tracks in Depression/Cyclonic Storm Tracks in GHG Scenarios.GHG Scenarios.

• Frequency of Depressions/Cyclones.Frequency of Depressions/Cyclones.• Intensity of Storms.Intensity of Storms.

Criteria adopted for the identification of cyclonic storms

(this includes severe storms and monsoon depressions)

At least 2 At least 2 daysdays

DurationDuration

> 15 m/s> 15 m/sMax. Wind Max. Wind SpeedSpeed

< -5hPa< -5hPaSLP SLP DepartureDeparture

Local Local MinimumMinimum

Sea level Sea level Pressure Pressure (SLP)(SLP)

A typical Monsoon Depression as simulated in the regional modelA typical Monsoon Depression as simulated in the regional model

Monsoon Monsoon Depression Depression Tracks as Tracks as simulated in simulated in HadRM2 control HadRM2 control and GHG and GHG ExperimentsExperiments

Pre and Post-Pre and Post-Monsoon Monsoon Cyclonic Storms Cyclonic Storms and likely and likely Changes in GHG Changes in GHG RunsRuns

Frequency of monthly cyclonic disturbances (Max intensity in m/s) as simulated by HadRM2 for 2041-60

NATCOM Workshop, IIM NATCOM Workshop, IIM Ahmedabad, 22.7.2003Ahmedabad, 22.7.2003

Likely Changes in Extreme Rainfall and TMAX/TMIN

Temperatures in India

Location of Stations

Considered in Extreme

Temperature Analysis

Simulation of No. Simulation of No. of Rainy Days in of Rainy Days in the Hadley the Hadley Center Regional Center Regional Model and likely Model and likely future changes future changes in 2041-60in 2041-60

Intensity (mm/day) of Rainfall per

rainy day and likely future changes in 2041-2060

Impact of Climate Change

on the daily Extreme Rainfall (cm) amounts in

India

Impact of Climate Change

on the daily Extreme Tmax. (Deg. C) India

Impact of Climate Change

on the daily Extreme Tmin. (Deg. C) India