Centre for Atmospheric and Oceanic Sciences
Indian Institute of Science, Bengaluru, KA, India
My research group works on tropical climate variability with special emphasis on Indian summer monsoon.
The frequency of extreme rainfall events of Indian summer monsoon has increased significantly during past seven decades. At the same time, the variance of low frequency intraseasonal oscillation (LF-ISO) and mean of the Indian summer monsoon rainfall decreased steadily. Are those contrasting changes physically connected?
In a recent research, we found that increase in extreme events during break phase of Indian summer monsoon can decrease its LF-ISO variance and seasonal mean. This is due to thermodynamic stabilization of the atmosphere and disorganization of large-scale circulation after an extreme rainfall event.References:
The date of onset of Indian summer monsoon shows substantial interannual variations. Monsoon onset isochrones gradually advance from southern tip of India to north and central regions, and then to northwest regions of the country. What determines the interannual variations of onset date over central India?
We show that in May, at least a month before the onset over central India, surface pressure anomalies over west Asia is lower than normal for an early onset year. A lower than normal surface pressure increases the strength of the cross equatorial Somaji Jet than brings more moisture over Indian land. Increase in moisture decreases stability of the atmosphere, and helps early onset over both south and central India. Similar results are found in numerical experimentsusing a state of the art general circulation model.
Such surface pressure anomalies propagate from west to east along 20-30N latitude band with speed equivalent to mid-latitude Rossby wave. This advances the potential predictability of date of onset of monsoon.References:
Chakraborty, A., Ravi S. Nanjundiaha, and J. Srinivasan, 2014: Local and remote impacts of direct aerosol forcing on Asian monsoon, Int. J. Climatology, DOI: 10.1002/joc.3826.
Bhattacharya, A., Arindam Chakraborty and V Venugopal, 2014: Variability of cloud liquid water and ice over South Asia from TMI estimates, Climate Dynamics, DOI 10.1007/s00382-013-1978-3.
Chakraborty, A, and Ravi S Nanjundiah, 2014: Role of Orography in Modulating Space-time Scales of Convection over South Asia, Theoretical and Applied Climatology, DOI 10.1007/s00704-013-0963-4.2013
Jain, D. K., Arindam Chakraborty, and R S Nanjundiah, 2013: Role of the cloud adjustment time scale in simulation of the interannual variability of Indian summer monsoon, Meteorology and Atmospheric Physics, 122:159-173.
Ramasesha, S and Arindam Chakraborty, 2013: Power generation using wind energy in northwest Karnataka, India, Current Science, 104, 757-761.2012
Chakraborty, A and R S Nanjundiah, 2012: Space-time Scales of Northward Propagation of Convection During Boreal Summer, Monthly Weather Review, 140, 3857-3866.
Krishnamurti, T. N., Anu Simon, Aype Thomas, Akhilesh Mishra, Dev Sikka, Dev Niyogi, Arindam Chakraborty, Li Li, 2012: Modeling of Forecast Sensitivity on the March of Monsoon Isochrones from Kerala to New Delhi, The First 25 Days, J. Atmospheric Science, 69, 2465-2487.
Meehl, Gerald A., Julie M. Arblaster, Julie M. Caron, H. Annamalai, Markus Jochum, Arindam Chakraborty, Raghu Murtugudde, 2012: Monsoon Regimes and Processes in CCSM4. Part I: The Asian–Australian Monsoon. J. Climate, 25, 2583–2608.
Jain, D. K., Arindam Chakraborty, and R S Nanjundiah, 2012: On the role of cloud adjustment time scale in simulating precipitation with Relaxed Arakawa–Schubert convection scheme, Meteorology and Atmospheric Physics, 115, 1-13.2010
Chakraborty, A., 2010: The Skill of ECMWF Medium Range Forecasts During the Year of Tropical Convection 2008, Monthly Weather Review., 138, 3787-3805. [PDF]
Krishnamurti, T. N., Arindam Chakraborty, and A. K. Mishra, 2010: Improving multimodel forecasts of the vertical distribution of heating using the TRMM profiles, J. Climate, 23, 1089-1094.2009
Krishnamurti, T. N., R. Krishnamurti, A. D. Sagadevan, Arindam Chakraborty, W. K. Dewar, C. A. Clayson, and J. F. Tull, 2009: Space-time stuctures of earth-quakes, Meteorology and Atmospheric Physics, 105, 69-83.
Chakraborty, A., and T. N. Krishnamurti, 2009: Improving global model precipitation forecasts over India from downscaling and FSU superensemble. Part II: Seasonal climate, Monthly Weather Review, 137, 2736-2757.
Krishnamurti, T. N., A. K. Mishra, Arindam Chakraborty, and M. Rajeevan, 2009: Improving Global Model Precipitation Forecasts over India Using Downscaling and the FSU Superensemble. Part I: 1–5-Day Forecasts, Monthly Weather Review, 137, 2713-2735.
Krishnamurti, T. N., A. D. Sagadevan, Arindam Chakraborty, A. K. Mishra, A. Simon, and S-H Chen, 2009: Improving Multimodel Forecast of Monsoon Weather over China using FSU Superensemble, Advances in Atmospheric Sciencese, 26, 813-839.
Krishnamurti, T. N., Arindam Chakraborty, Andrew Martin, William K Lau, Kyu-Myong Kim, Yogesh Sud and Gregory Walker, 2009: Impact of Arabian Sea Pollution on the Bay of Bengal Winter Monsoon Rains, Journal of Geophysical Research: Atmosphere, 114, D06213, doi:10.1029/2008JD010679.
Chakraborty, A., Ravi S. Nanjundiah, and J. Srinivasan, 2009: Impact of African Orography and Indian Summer Monsoon on the Low-Level Somali Jet, International Journal of Climatology, 29, 983-992.2008
Chakraborty, A., and T. N. Krishnamurti, 2008: Improved forecasts of diurnal cycle in tropics using multiple global models. Part II: Asian Summer Monsoon, Journal of Climate, 21, 4045–4067.
Krishnamurti, T. N., C. Gnanaseelan, A. K. Mishra and Arindam Chakraborty, 2008: Improved Forecasts of Diurnal Cycle in Tropics Using Multiple Global Models. Part I: Precipitation, Journal of Climate, 21, 4029–4043.2007
Krishnamurti, T. N., Arindam Chakraborty, R. Krishnamurti, W. K. Dewar, and C. Clayson, 2007: Passage of intraseasonal waves in the subsurface oceans, Geophysical Research Letters, 34, doi: 10.1029/2007GL030496.
Chakraborty, A., T. N. Krishnamurti and C. Gnanaseelan, 2007: Prediction of the Diurnal Cycle using a Multimodel Superensemble. Part II: Clouds, Monthly Weather Review, 135, 4097-4116.'
Krishnamurti, T. N., C. Gnanaseelan, and Arindam Chakraborty, 2007: Prediction of the Diurnal Cycle using a Multimodel Superensemble. Part I: Precipitation, Monthly Weather Review, 135, 3613-3632.
Ross, R. S., Arindam Chakraborty, Anthony Chen, and T. N. Krishnamurti, 2007: Improved Seasonal Climate Forecasts for the Caribbean Region using a Multi-Model Superensemble, Meteorology and Atmospheric Physics, doi: 10.1007/s00703-006-0234-3.
Sirdas, S., Robert S. Ross, T. N. Krishnamurti and Arindam Chakraborty, 2007: Evaluation of the FSU Synthetic Superensemble Performance for Seasonal Forecasts over the Euro-Mediterranean Region, Tellus-A, 59, 50-70.2006
Chakraborty, A., R. S. Nanjundiah, and J. Srinivasan, 2006: Theoretical aspects of the onset of Indian summer monsoon from perturbed orography simulations in a GCM, Annales Geophysicae, 24, 2075-2089.
Krishnamurti, T. N., Arindam Chakraborty, R. Krishnamurti, W. K. Dewar, C. A. Clayson, 2006: Seasonal Prediction of Sea Surface Temperature Anomalies Using a Suite of 13 Coupled Atmosphere-Ocean Models, Journal of Climate, 19, 6069-6088.
Chakraborty, A., T. N. Krishnamurti, 2006: Improved Seasonal Climate Forecasts of the South Asian Summer Monsoon Using a Suite of 13 Coupled Ocean-Atmosphere Models, Monthly Weather Review, 134, 1697-1721.Prior to 2006
Chakraborty, A., S. K. Satheesh, R. S. Nanjundiah, and J. Srinivasan, 2004: Impact of absorbing aerosols on the simulation of climate in the Indian region in an atmospheric general circulation model. Annales Geophysicae., 22, 1421-1434.
Chakraborty, A., and J. Srinivasan, 2003: Comparison of radiative fluxes at the top of the atmosphere from INSAT and ERBE, Mausam, 54, 299-314.
Chakraborty, A., R. S. Nanjundiah, and J. Srinivasan, 2002: Role of Asian and African orography in Indian summer monsoon., Geophysical Research Letters, 29, 10.1029/2002GL015522.
Bhat, G. S., Arindam Chakraborty, R. S. Nanjundiah and J. Srinivasan, 2002: Vertical thermal structure of the atmosphere during active and weak phases of convection over the north Bay of Bengal: Observation and model results, Current Science, 83, 296-302.
Along with Prof Ravi S Nanjundiah Thesis Topic:Cumulus convection parameterization across scales.
Along with Prof Ravi S Nanjundiah
Thesis Topic:Effect of western Ghats Orography on Monsoon Climate of the Bay of Bengal Cool Pool
Thesis Topic:Role of land-atmosphere interaction on onset and intraseasonal variations of Indian summer Monsoon.
Along with Prof Ravi S Nanjundiah
Thesis Topic:Tropical teleconnection and monsoon intraseasonal oscillation on decadal time scale.
Along with Prof Debasis Sengupta
Thesis Topic:Tropical intraseasonal oscillation in idealized framework.
Along with Prof J Srinivasan
Thesis Topic:Global Monsoon variability at the paleo time scale.
Thesis Topic:Urban Climate and its interaction with monsoon.
Thesis Topic:Short-range forecast skill of numerical models.