High-resolution modelling of regional climate change scenario over South Asia R. Krishnan Centre for Climate Change Research Indian Institute of Tropical Meteorology, Pune Seminar on Socio Economic Implications of Climate Change Initiatives: Priorities and Implications for India Geospatial World Forum Hyderabad 18 – 21 January, 2011

An Elegant Science Question: Are increases in greenhouse gases responsible for increase in global mean temperature (global warming)? 0.76°C (1.4°F) since °C (1.0°F) since Global Temperature & Carbon Dioxide

Greenhouse gases increase due to human activities. Global warming is due to increases in greenhouse gases. Global warming is due to human activities. Hypothesis Alternative Hypothesis Global warming is due to natural variations of climate. How do you test such hypotheses? Climate Models; IPCC

Equations of motions and laws of thermodynamics to predict rate of change of: T, P, V, q, etc. (A, O, L, CO 2, etc.) 10 Million Equations: 100,000 Points × 100 Levels × 10 Variables With Time Steps of: ~ 10 Minutes Use Supercomputers What is a Climate Model?

IPCC º C Increase in Surface Temperature Observations Predictions with Anthropogenic/Natural forcings Predictions with Natrual forcings

Challenges in assessment of future changes in South Asian monsoon rainfall Wide variations and uncertainties among the IPCC AR4 models in capturing the mean monsoon rainfall over South Asia (eg., Kripalani et al. 2007, Annamalai et al. 2007). Systematic biases in simulating the spatial pattern of present-day mean monsoon rainfall (eg., Gadgil and Sajani, 1998; Kripalani et al. 2007) Realism of present-day climate simulation is an essential requirement for reliable assessment of future changes in monsoon

South Asia (5-35N, 65-95E)) Source: Kripalani et al. 2010

Summer monsoon precipitation IPCC models: 20C3M Observed rainfall (JJAS) The 20c3m simulations attempt to replicate the overall climate variations during the period ~1850-present by imposing each modeling groups best estimates of natural (eg., solar irradiance and volcanic aerosols) and anthropogenic (eg. GHG, sulfate aerosols and ozone) during this period. Seven 20C3M models (GFDL CM2.0, GFDL-CM2.1, MPI-ECHAM5, MRI, MIROC3-HIRES, HadCM3, NCAR-PCM – Source: J. Shukla)

Long-term mean of JJAS rainfall (mm) JJAS cumulative rainfall ( ) Area average (90E – 97E ; 20N – 30N) IMD gridded rainfall dataset Interannual variability of monsoon rainfall over Northeast India

Questions : On Attribution?  How much of the observed variability of the mean Indian Summer Monsoon rainfall due to Climate Change? How much of the observed increase in temperature over India been decreased by increasing presence of aerosols? How much of the observed increase in temperature over India been decreased by increasing presence of aerosols? Questions : On Projections of Monsoon  What will happen to the monsoon hydrological cycle years from now under different scenarios? In particular, will the quantum of seasonal mean rainfall increase or decrease and if so by how much?  What is the uncertainty in these projections? Can we quantify this uncertainty?  How can we reduce this uncertainty?

Some indicators of regional monsoon climate Observed changes in frequency of monsoon depressions during the last century Changes in the observed extreme rainfall events during the 20 th century Question: Attribution: How much of the observed regional monsoon variability is due to global warming?

All India summer monsoon rainfall variability Climatological Mean (JJAS) Interannual Variability Goswami et al., Science, 2006

Time series of count over CI Low & Moderate events Heavy events (>10cm) V. Heavy events (>15cm)

Frequency as well as intensity of heavy & very-heavy rainfall events have significantly increased over Central India Low and moderate events have significant decreasing trend over Central India The seasonal mean does not have a trend because decreasing contribution from low and moderate events are compensated by increasing contribution from heavy events Increase in intensity of extreme events Goswami et al 2006

Possible causes for the decreasing trend in the moderate rainfall events ? Possible causes for the decreasing trend in the moderate rainfall events ? Long-term trends in the large-scale monsoon circulation ? Long-term trends in the large-scale monsoon circulation ? Indications of weakening of the low-level monsoon flow (Joseph and Simon 2005) Indications of weakening of the low-level monsoon flow (Joseph and Simon 2005) Increasing frequency of “breaks” in monsoon rainfall (Ramesh Kumar et al. 2009) Increasing frequency of “breaks” in monsoon rainfall (Ramesh Kumar et al. 2009) Zonal wind averaged over (12.5N – 17.5N; 70 E – 85 E)

Decreasing frequency of monsoon depressions during last 2-3 decades (eg., Rajeevan et al., 2000; Amin and Bhide, 2003; Dash et al., 2004) Recovery in the activity of monsoon depressions during the recent years (2005 – 2007) Activity of monsoon depressions modulated by low-frequency variability of atmospheric large-scale circulation on inter-decadal time-scales Time series of frequency of monsoon depressions

Strategy on Regional Climate Change Research at IITM Centre for Climate Change Research (CCCR) Ministry of Earth Sciences, Govt. of India To build capacity in the country in high resolution coupled ocean-atmosphere modelling to address issues on Attribution and Projection of regional Climate Change To build capacity in the country in high resolution coupled ocean-atmosphere modelling to address issues on Attribution and Projection of regional Climate Change  Earth System Model (ESM) To provide reliable input for Impact Assessment studies To provide reliable input for Impact Assessment studies  Dynamic downscaling of regional monsoon climate using high resolution models; quantification of uncertainties Observational monitoring: Network with other Institutions Observational monitoring: Network with other Institutions

Modelling ProgramObservational Program  To establish a High Altitude Cloud Physics Observatory for monitoring cloud-aerosol interactions – (Long-term)  To understand Past Changes in Monsoon Climate using Multiple Proxy Records. Reconstruction of an iconic monsoon index going back to a few thousand years – (Long-term)  To promote Outreach and Training for Capacity Building in Climate Change Research and Dissemination of Information – Long-term cont  To build a Global High-resolution Earth System Model to address the Attribution & Projection of regional climate change – (Long-term)  To generate regional climate change scenarios for South Asia using Ultra High-resolution Regional Climate Models and quantify uncertainties. Provide reliable inputs for impact assessments. Contribute to IPCC AR5 – (Short-term) Objectives

High resolution regional climate change scenarios and quantification of uncertainties Provide reliable inputs for impact assessments and contribute to IPCC AR5  High resolution dynamic downscaling of monsoon: Baseline climate runs using WRF, RegCM and LMDZ partially completed. Future climate scenario runs to be initiated in January  Two member 19 year (1989 : 2007) run of WRF (50 km) model completed. ERA Interim LBC  One member 19 year (1989 : 2007) run of RegCM (50 km) model completed. ERA Interim LBC  One member 10 year (1979 : 1988) run of LMDZ (50 km) model completed

CRU ERAIM WRF – KF2 CRU ERAIM WRF – BM CRU ERAIM RegCM - EML CRU ERAIM RegCM - GRL CRU ERAIM PRECIS CRU ERAIM LMDZ Jan Apr Jul Oct Jan Apr Jul Oct Monthly mean annual cycle of surface air temperature over Indian land region

Jan Apr Jul Oct Jan Apr Jul Oct IMD CMAP WRF – KF2 IMD CMAP WRF – BM IMD CMAP RegCM - EML IMD CMAP RegCM - GRL IMD CMAP PRECIS IMD CMAP LMDZ Monthly mean annual cycle of precipitation (mm/day) over Indian land region

LMD model 1 degree (Global) LMDZ model 1/3 degree zoom for Monsoon Domain (40-110E; 15S-30N) & 1 degree outside Initial runs made at CCCR on PRITHVI, IITM JJAS SLP and winds 850 hPa JJAS rainfall High resolution monsoon simulations: Global model with zoom over monsoon domain

LMDZ monsoon simulation at 50 km zoomed resolution – 10 year mean Mean SLP and 850 hPa winds (JJAS) Mean rainfall (JJAS) Large scale structure of winds and SLP is well captured Monsoon Trough has strong southward dip over eastern India and Bay of Bengal – Bias Precipitation along West Coast and Central - Eastern India is reasonably well simulated Rainfall over north Bay of Bengal is underestimated. Excessive rain over central Bay of Bengal Rainfall over Equatorial Eastern Indian Ocean is underestimated

Example of a monsoon depression in a typical synoptic chart

LMDZ simulation: Rainfall and 850 hPa streamlines during a typical monsoon low / depression Day 01Day 02Day 03Day 04 Day 05Day 06Day 07Day 08 Day 09Day 10Day 11Day 12 Day 13Day 14Day 15Day 16

LMDZ simulation: Evolution of SLP anomalies during a typical monsoon depression Day 01 Day 02Day 03Day 04 Day 05Day 06Day 07Day 08 Day 09 Day 10 Day 11 Day 12 Day 13Day 14Day 15Day 16

Earth System Model (ESM) development Start with an atmosphere-ocean coupled model which has a realistic mean climate – eg. NCEP CFS Fidelity in capturing the global and monsoon climate Realistic representation of monsoon interannual variability Features of ocean-atmosphere coupled interactions … Include components of the ESM Aerosol and Chemistry Transport Module Biogeochemistry Module (Terrestrial and Marine) Sea-ice module ….

Climatological (JJAS) mean monsoon rainfall from CFS model – 100 year free run Climatological (JJAS) mean SST from CFS model – 100 year free run

Taylor diagram of spatial pattern of climatological seasonal mean (JJAS) rainfall CFS Model High pattern correlation with observed rainfall over India (IMD gridded Dataset) Source: Seasonal Prediction Group, IITM

CFS model JJAS climatological mean rain rate = 5.80 mm / day (red line) Standard Deviation of JJAS rain rate = 0.82 mm / day Observed rainfall (IMD) JJAS climatological mean rain rate = 7.5 mm /day Standard Deviation = 0.85 mm / day Interannual variability of summer monsoon rainfall in the CFS model – 100 year free run Domain: 70E-90E; 10N-30N Time in years

CFSv2 precip JJAS 10 yr mean CMAP precip JJAS ( ) CFSv1 precip JJAS 100 yr mean CFSv2 runs on PRITHVI by CCCR

Ongoing efforts towards development of Earth System Model (ESM) to address the Scientific Challenges of Global Climate Change and the Asian Monsoon System Plan to include ESM components in the CFS-2 coupled ocean-atmosphere model Plan to include ESM components in the CFS-2 coupled ocean-atmosphere model CFS-2 coupled ocean-atmosphere model simulations on HPC initiated CFS-2 coupled ocean-atmosphere model simulations on HPC initiated Ocean Biogeochemistry Module coupled to MOM4. Runs are ongoing on HPC Ocean Biogeochemistry Module coupled to MOM4. Runs are ongoing on HPC Aerosol Transport Module coupled to AGCM. Runs are ongoing on HPC Aerosol Transport Module coupled to AGCM. Runs are ongoing on HPC Basic structure of ESM

CCCR Features of Dynamic Climate Data Portal  Visualize data with on-the-fly graphic  Easy and user friendly analysis of climate data through graphical display on the browser with one click  Example : IMD daily rainfall (1951 to 2009)  URL:  Step 1: Click on the above URL Centre for Climate Change Research Indian Institute of Tropical Meteorology, Pashan, Pune – Ministry of Earth Sciences, Govt. of India CCCR Climate Data Web Portal

Summary  Dynamic downscaling of regional monsoon climate using high resolution models. Efforts have been initiated at CCCR.  Downscaling simulations of present day and future monsoon climate scenarios will be completed by early 2012 (PRECIS, WRF, RegCM, LMDZ)  Contribute to IPCC AR5 report through its activity  Quantify uncertainties in regional monsoon projections using results from multiple models  Also employ bias correction techniques for reducing model errors  Share model data & conduct inter-disciplinary collaborative research towards impact assessment, vulnerability and adaptation.  Hydrological Modeling to be started at CCCR soon  Long term plans (~ 3-4 years) to develop an Earth System Model (ESM)  A global atmosphere-ocean coupled model (CFS) is operational. A century long simulation and several other runs have been performed  Aspects of global and regional monsoon climate are realistically captured by CFS model  Realistic features of monsoon interannual variability is seen from the CFS simulations (e.g., Atmosphere-ocean coupling over tropical Indo-Pacific, Monsoon and mid-latitude interactions, etc)  Plans to improve the simulation of present day monsoon climate in the CFS model. Need to reduce model systematic biases.  Ongoing efforts to include ESM components in CFS model (ie., Aerosol transport module, Marine and Terrestrial Ecosystem and Biogeochemistry module, Sea-Ice module, etc).