Publications

You can also find my publication details in Google Scholar and ORCID

Publications

1. Sharma, Tanu., S. B. Ratna, D.S. Pai, Arti Bandgar, M. Rajeevan, M. Mohapatra, O.P. Sreejith, K.S. Hosalikar, 2024: Indian Summer Monsoon Rainfall Response to Two Distinct Evolutions of La Niña Events, International Journal of Climatology, https://doi.org/10.1002/joc.8588 (In Press).

2. Karrevula, N. R., D. A. Ramu, S. B. Ratna, P. Satish, 2024: Indian Ocean warming, extreme positive Indian Ocean Dipole events, and their impact on monthly Indian Monsoon rainfall from June to November in NMME models, Atmospheric Research, 309, 107572, https://doi.org/10.1016/j.atmosres.2024.107572.

3. Musale, M., Sharma, T., Ratna, S. B., C. T. Sabeerali, P. Rohini, A. Bandgar, O. P. Sreejith and K. S. Hosalikar, (2024): Triple-dip La Niña (2020-2022) and its impact on Indian Summer Monsoon Rainfall: Insight from the Monsoon Mission Coupled Forecasting System, Mausam, 75,3, 769–782, https://doi.org/10.54302/mausam.v75i3.6283

4. Pagire, Arvind and Ratna, S B. and Chattopadhyay, R., and Sreejith, O.P., 2024: A Deep Learning Algorithm for Classification of Precipitation Extremes Over Vidarbha Region in Central India. Available at SSRN: http://dx.doi.org/10.2139/ssrn.4875891

5. Sahu, N., Das, P., Ratna, S.B., Saini, A., Mallick, S.K., Kumar, A., & Mohapatra, M. 2024: A bibliometric analysis for Indian summer monsoon variability. Spat. Inf. Res. https://doi.org/10.1007/s41324-024-00587-9

6. Ratna, S. B., C.T. Sabeerali, Tanu Sharma, D.S. Pai, M. Mohapatra, 2024: Combined influence of El Niño, IOD and MJO on the Indian Summer Monsoon Rainfall: Case Study for the years 1997 and 2015, Atmospheric Research, 299, 107214, Available at https://doi.org/10.1016/j.atmosres.2023.107214.

7. Sharma, T., S. B. Ratna, D. S. Pai, 2023: Modulation of Indian Summer Monsoon Rainfall response to ENSO in the recent decades and its large-scale dynamics, Research Square (3 January 2023). Available at https://doi.org/10.21203/rs.3.rs-2405719/v1

8. Ratna, S. B., Tanu Sharma, Arti Bandgar, et al. 2023: Asymmetry in the Indian Summer Monsoon Rainfall response to two types of La Niña evolution. Authorea (March 06, 2023). Available at  https://doi.org/10.22541/essoar.167810382.22543492/v1 

9. Sahu, N., Das, Pritiranjan and S. B. Ratna, and Saini, Atul and Mallick, Suraj Kumar and Kumar, Anil and Mohapatra, Mrutyunjay, 2022:  Indian Summer Monsoon Variability Studies in India: A Review and Bibliometric Analysis,  SSRN (December 31, 2022). Available at http://dx.doi.org/10.2139/ssrn.4315989

10. Bandgar, Arti B., O. P. Sreejith, S. B. Ratna, Sabeer Ali and & D. S. Pai (2022): Monsoon 2021: Global and Regional Circulation Anomalies, PP 23-44, IMD Met. Monograph: MoES / IMD / SYNOPTIC MET / 01(2022)26

11. Sreejith, O.P., D. S. Pai, Aarti Bandgar, Divya Surendran, Madhuri M Musale, Sakha Sanap, Bharti S Sable, Smitha Anil, Mahendra Benke and S. B. Ratna (2022): Verification Operational and Experimental Long-Range Forecast during Southwest Monsoon 2021, PP 23-44, IMD Met. Monograph: MoES / IMD / SYNOPTIC MET / 01(2022)26

12. Goodess, C., Berk, S., Ratna, S. B., Brousse, O., Davies, M., Heaviside, C., Moore, G., & Pineo, H. (2021). Climate change projections for sustainable and healthy cities. Buildings and Cities, 2(1), pp. 812–836. DOI: https://doi.org/10.5334/bc.111

13. Cherchi A, Terray P, Ratna SB, Sankar S, Sooraj KP, Behera S (2021) Indian Ocean Dipole influence on Indian summer monsoon and ENSO: a review. Chapter 8 in "Indian summer monsoon variability - El Nino Teleconnections and beyond", Chowdary JS, Parekh A, Gnanaseelan C eds. Elsevier, ISBN: 978-0-12-822402-1, https://doi.org/10.1016/B978-0-12-822402-1.00011-9 

14. Ratna, S. B., A. Cherchi, T. J. Osborn, M. Joshi, and U. Uppara, 2021: The Extreme Positive Indian Ocean Dipole of 2019 and Associated Indian Summer Monsoon Rainfall Response, Geophysical Research Letters, https://doi.org/10.1029/2020GL091497

15. Ratna, S. B., T. J. Osborn, M. Joshi, and J. Luterbacher, 2020: The influence of Atlantic variability on Asian summer climate is sensitive to the pattern of the sea surface temperature anomaly, Journal of Climate, 33, 17, 7567-7590. https://doi.org/10.1175/JCLI-D-20-0039.1

16. Talento, S., T.J. Osborn, M.Joshi, S. B.Ratna and J.Luterbacher, 2020: Response of the Asian Summer Monsoons to a High-latitude Thermal Forcing: Mechanisms and Nonlinearities, Climate Dynamics, 54, 3927–3944. https://doi.org/10.1007/s00382-020-05210-9.

17. Ratna, S. B., Osborn, T. J., Joshi, M., Yang, B., and Wang, J., 2019: Identifying teleconnections and multidecadal variability of East Asian surface  temperature during the last millennium in CMIP5 simulations, Clim. Past, 15, 1825–1844, https://doi.org/10.5194/cp-15-1825-2019.

18. Cherchi, A., S.B. Ratna, S Masina, A Storto, C Yang, C Fratianni, S Simoncelli, N Pinardi, 2018: Evaluation of AMIP-type atmospheric fields as forcing for regional and global oceanic reanalyses, Annals of Geophysics, 61, 1-24. DOI: 10.4401/ag-7793.

19. Abish, B., A. Cherchi, S. B. Ratna, 2017: ENSO and the recent warming of the Indian Ocean, Int. J. Climat, DOI: 10.1002/joc.5170.

20. Ratnam, J. V., S. K. Behera, R. Krishnan, T Doi, S. B. Ratna, 2017: Sensitivity of Indian summer monsoon simulation to physical parameterization schemes in the WRF model, Climate Research, 74, 43-66. DOI: https://doi.org/10.3354/cr01484.

21. Ratna, S.B., J. V Ratnam, S.K. Behera, A. Cherchi, W. Wang, T. Yamagata, 2017: The unusual wet summer (July) of 2014 in South Europe, Atmospheric Research, 189, 61-68.

22. Ratna, S.B, Ratnam, J.V., Behera, S.K. Tangang, F, and Yamagata, 2017: Validation of the WRF regional climate model over the subregions of Southeast Asia: Climatology and interannual variability, Climate Research, 71, 263-280.

23. J. V. Ratnam, S. B. Ratna, S. Behera, C.J.deW. Rautenbach, Keiko Takahashi, and Toshio Yamagata (2016) Dynamical downscaling of seasonal climate in Southern Africa. In: S. Behera and T. Yamagata (ed) Indo-Pacific Climate Variability and Predictability, World Scientific Series on Asia-Pacific Weather and Climate: Volume 7, World Scientific, Singapore, pp.265-279. doi: 10.1142/9789814696623_0009.

24. Ratnam, J. V., S. K. Behera, H. Annamalai, S. B. Ratna, M. Rajeevan and T. Yamagata, 2016: ENSO’s far reaching connection to Indian cold waves, Sci. Rep. 6, 37657; doi: 10.1038/srep37657

25. Ratnam, J. V., S. K. Behera, S. B. Ratna, M. Rajeevan and T. Yamagata, 2016: Anatomy of Indian heatwaves. Scientific Reports, 6, 24395; doi: 10.1038/srep24395.

26. Ratnam, J., S. Behera, T. Doi, S. B. Ratna, and W. Landman, 2016: Improvements to the WRF seasonal hindcasts over South Africa by bias correcting the driving SINTEX-F2v CGCM fields. J. Climate. 29, 2815-2829. https://doi.org/10.1175/JCLI-D-15-0435.1

27. Ratna, S. B., A. Cherchi, P.V. Joseph, S. Behera, Abish B., S. Masina, 2016: Moisture variability over the Indo-Pacific region and its influence on the Indian summer monsoon rainfall. Climate Dynamics, 46, 949-965.

28. Ratna, S. B., J. V. Ratnam, S. Behera, C.J.deW. Rautenbach, T. Ndarna, Keiko Takahashi, and Toshio Yamagata, 2014: Performance assessment of three convective parameterisation schemes in WRF for downscaling summer rainfall over South Africa. Climate Dynamics, 42, 2931–2953.

29. Ratna, S. B., A. Cherchi, P.V. Joseph, S. Behera, Abish B., S. Masina, 2014: Moisture trend over the Arabian Sea and its influence on the Indian summer monsoon rainfall. Research Report, RP0225, Euro-Mediterranean Center on Climate Change, Bologna, Italy, 29pp.

30. Ratnam, J. V., S. K. Behera, S. B. Ratna, H. Rautenbach, C. Lennard, J-J Luo,  Y. Masumoto, K. Takahashi and T. Yamagata, 2012: Dynamical downscaling of austral summer climate forecasts over southern Africa using a simple regional coupled model, Journal of Climate,  26, 6015–6032.

31. Ratna, S. B., Swadhin Behera, J. Venkata Ratnam, Keiko Takahashi, and Toshio Yamagata, 2012: An index for tropical  temperate troughs over southern Africa. Climate Dynamics,  41:421–441.

32. Ratna, S. B.,  S. Behera, J. V. Ratnam, H. Rautenbach, T. Ndarana, K. Takahashi and T. Yamagata (2012): Downscaling extreme summer season rainfall over South Africa using the high resolution WRF model. 28th Annual conference of South African Society for Atmospheric Sciences, 26-27 September 2012, CAPETOWN, South Africa. ISBN 978-0-620-53375-1. 

33. Bhaskar Rao, D.V., S. B. Ratna and D. Srinivas, 2013: An Assessment of Cumulus Parameterization schemes in the Short Range Prediction of Rainfall during the Onset Phase of the Indian Southwest Monsoon using MM5 Model. Atmospheric Research, 120, 249-267.

34. Badarinath, K.V.S., D.V. Mahalakshmi, and S. B. Ratna, 2012: Influence of Land Use Land Cover on Cyclone Track Prediction – A Study During Aila Cyclone. The Open Atmospheric Science Journal, 6, 33-41.

35. Ratna, S. B., J. V. Ratnam, Swadhin Behera, K. Takahasi and Toshio Yamagata, 2011: Simulation of 2010/11 Summer Season Heavy Rainfall Events over Southern Africa Using WRF Model. 27th Annual conference of South African Society for Atmospheric Sciences, 22-23 September 2011, Hartbeespoort, North-West Province, South Africa. ISBN 978-0-620-50849-0.

36. Sikka, D.R. and S. B. Ratna, 2011: On improving the ability of a high resolution atmospheric general circulation model for dynamical seasonal prediction of the extreme seasons of the Indian summer monsoon. Mausam, 62 (3), 339-360.

37. Ratna, S. B., 2011: Summer Monsoon Rainfall variability over Maharashtra, India. Pure and Applied Geophysics, 169, 259-273.

38. Ratna, S. B., D. R. Sikka, M. Dalvi and J. V. Ratnam, 2011: Dynamical Simulation of Indian Summer Monsoon Circulation, Rainfall and its Interannual Variability Using a High Resolution Atmospheric General Circulation Model, International Journal of Climatology, 31, 1927-1942.

39. Bhaskar Rao, D.V. and S. B. Ratna, 2010: Mesoscale characteristics and prediction of an unusual extreme heavy precipitation event over India using a high resolution mesoscale model. Atmospheric Research, 95 (2), 255-269.

40. Bhaskar Rao, D.V., D. Srinivas, and S. B. Ratna, 2008: Regional scale prediction of the onset phase of the Indian southwest monsoon with a high-resolution atmospheric model, Atmospheric Science Letters, 9(4), 237 – 244.

Thesis/Dissertation

1. Ratna, S. B, 2009: Prediction of onset phase, heavy rainfall events and regional characteristics of the Indian southwest monsoon using numerical models. Ph.D. thesis in Meteorology, Andhra University, Visakhapatnam.

2. Ratna, S. B, 2004: Sensitivity of July 1998 Regional Climate Simulation to Land Surface Parameterization. M.Tech. Dissertation in Atmospheric Science, Andhra University, Visakhapatnam.

Data

1. Ratna, S.; Osborn, T.; Joshi, M. (2020): INTEGRATE: climate model simulations data to study the Asian climate response to Atlantic Multidecadal Oscillation (AMO) using the Intermediate General Circulation Model version 4 (IGCM4). Centre for Environmental Data Analysis, 17 June 2020. doi:10.5285/3f2f92ad04f84e65a2399deeafd8bbbc. http://dx.doi.org/10.5285/3f2f92ad04f84e65a2399deeafd8bbbc

Invited Talks/Guest Lectures

1. Distinguished Alumni Lecture "Seasonal forecast activities at the India Meteorological Department” at the Department of Marine Sciences, Berhampur University, Odisha, India on 18 March 2023.

2. "ENSO forecast at the Indian Meteorological Department (IMD)” at the Scoping Workshop on the WMO recognized entity supporting El Niño/La Niña information organised by WMO at Pune during 6-8 December 2022.

3. "Development of National Framework for Climate Services in India: (NFCS – India)” at the national symposium TROPMET-2022 held in IISER, Bhopal during 29 November - 2 December 2022.

4. “Seasonal climate outlook of South Asia for JJAS2022 -Global and Regional Perspectives” at SASCOF22 on 26 April 2022.

5. "Weather and Climate Prediction in India" for the UGC-Refresher course on Environmental Sciences for Assistant. Professors, organized by Utkal University, Bhubaneswar, Odisha on 2 March 2022.

6. “Seasonal climate outlook of South Asia for DJF 2021/22 -Global and Regional Perspectives” at SASCOF21 on 25 November 2021.

7. Multidecadal surface temperature variability over South and East Asia during the last millennium at the Department of Geography, Delhi School of Economics, Delhi University, Delhi, India.

8. Multidecadal climate variability over South and East Asia during the last millennium at the India Meteorological Department (HQ), New Delhi, India on 25 September 2018.

9. Multidecadal variability of South and East Asia Surface Temperature in CMIP5 simulations of the last millennium at the Department of Earth and Atmospheric Sciences, NIT Rourkela, India on 12 September 2018.

10. Dynamical Prediction of weather and climate at the Department of Marine Sciences, Berhampur University, Berhampur, India on 13 January 2017.

11. A tutorial lecture on Climate Data Operator (CDO) at Nansen Environmental Research Centre-India (NERCI), Kochi, India on 20 January 2014.

12. Resource person: INDO-MARECLIM winter school on climate change and variability, marine ecosystems and coastal zone management during 2-7 November, Kochi, India.

13. Downscaling summer seasonal climate over South Africa using the high resolution WRF model at the Department of Oceanography, University of Cape Town, Cape Town, South Africa on 4 October 2012.

14. Tropical – Extratropical Interaction and its association with ENSO at the Indian Institute of Tropical Meteorology (IITM), Pune, India on 7 December 2012.

15. Downscaling seasonal forecast over South Africa at the Centre for Development of Advanced Computing (CDAC), Pune, India on 7 December 2012.

16. Understanding a data analysis tool – GrADS at the South Africa Weather Services, Pretoria, South Africa on 24 February 2011.

17. A tutorial lecture on GrADS at the Department of Geography, University of Pretoria, Pretoria, South Africa on 25 February 2011.

18. Dynamical downscaling using regional climate model at the University of Western Cape, Cape Town, South Africa on 2 March 2011.

19. A lecture on Numerical weather prediction at the University of Rhodes, Grahamstown, South Africa on 7 March 2011.

Conference Presentation

1. Ratna, S. B., Timothy Osborn, Manoj Joshi (2020): East Asian surface temperature variability and its teleconnections with AMO and PDO in the CMIP5 simulations, 6th Climate Dynamics Workshop (Virtual) organized by BAS, Cambridge, UK (29-30 June 2020).

2. Ratna, S. B., Timothy Osborn, Manoj Joshi,  Juerg Luterbacher (2020): Response of South and East Asian summer climate to North Atlantic SST anomalies: sensitivity to SST patterns. Online presentation at EGU General Assembly 2020 (4-8 April 2020). https://doi.org/10.5194/egusphere-egu2020-2414

3. Ratna, S. B., Timothy Osborn, Manoj Joshi (2020): Patterns of Arctic amplification in CMIP5 and CMIP6 Projections. Online presentation at CMIP6 Poster Seminars (organised by the Met Office, UK), 20-21 April 2020. https://ukesm.ac.uk/cmip6/uk-cmip6-analysis-workshop-20-21-april-2020-met-office-exeter/ (VIDEO)

4. Ratna, S. B., Timothy Osborn, Manoj Joshi (2018): Multidecadal climate variability of East Asia during the last millennium: roles of external forcing and internal variability, American Geophysical Union (AGU) Fall Meeting, Washington D.C., USA, 10-14 December 2018.

5. Ratna, S. B., Timothy Osborn, Manoj Joshi, and Bao Yang (2018): Drivers of multidecadal variability of East Asian surface temperature in CMIP5 simulations of the last millennium, European Geosciences Union (EGU) General Assembly 2018, Vienna, Austria, 8–13 April 2018.

6. Ratna, S. B., J. V. Ratnam, S. K. Behera, T. Doi, T. Yamagata (2017): Validation of the regional climate model for the seasonal forecast over Southeast Asia, Workshop on "Application of Ocean and Climate Predictions" held in JAMSTEC, Yokohama, Japan during 25-26 January 2017.

7. Ratna, S. B., J. V. Ratnam, S. K. Behera, A. Cherchi, W. Wang, T. Yamagata (2016): The Unusual Wet Summer (July) of 2014 in Southern Europe and its Predictability using NCEP CFSv2 Model, S2S Extremes Workshop 2016, IRI, New York, USA, 31 July-5 August 2016.

8. Ratna, S. B., J. V. Ratnam, S. K. Behera, T. Doi, T. Yamagata (2016): Downscaled Prediction of Extreme Seasonal Climate over Southeast Asia using a Regional Climate Model, Techno-Ocean 2016, Kobe, Japan, 6 - 8 October 2016.

9. Ratna, S. B., J. V. Ratnam, S. K. Behera, A. Cherchi, W. Wang, T. Yamagata (2016): Wet Summer of 2014 over Southern Europe and its Relation with the Pacific Ocean, 13th Annual Meeting Asia Oceania Geosciences Society (AOGS 2015), Beijing, China, 31 July-5 August 2016.

10. Ratna, S. B., J. V. Ratnam, S. K. Behera, T. Doi, T. Yamagata (2016): Downscaling SINTEX-F2 Retrospective Seasonal Forecast over Southeast Asia Using WRF Regional Model, 13th Annual Meeting Asia Oceania Geosciences Society (AOGS 2015), Beijing, China, 31 July-5 August 2016.

11. Ratna, S. B., J. V. Ratnam, S. K. Behera, A. Cherchi, W. Wang, T. Yamagata (2016): The Unusual wet summer of 2014 in Southern Europe. Japan Geoscience Union (JpGU) meeting, held at the Makahari Messe, Chiba, Japan during 22-26 May, 2016.

12. Ratna, S. B., J. V. Ratnam, S. K. Behera, Fredolin T. Tangang, T. Yamagata (2016): Downscaling Southeast Asian Summer Monsoon climate using the Weather Research and Forecasting (WRF) Model. The International Science Conference  on MAHASRI (Monsoon Asian Hydro-Atmosphere Scientific Research and Prediction Initiative) held at Tokyo Metropolitan University, Tokyo, Japan during 2-4 March 2016. (link)

13. Ratna, S. B., J. V. Ratnam, S. K. Behera, T. Yamagata (2016): Downscaling seasonal climate variability over Southeast Asia and its association with the large-scale climate modes. Tropical Precipitation System Workshop 2015 held at JAMSTEC, Yokohama, Japan during 3-4 September 2015. (link)

14. Ratna, S. B., Annalisa Cherchi, P. V. Joseph, S. K. Behera, Abish. B., Simona Masina (2015) Impact of the Moisture Variability on the Indian Summer Monsoon Rainfall. 6th ISAJ Symposium on Recent Advances in Science and Technology held at Indian Embassy, Tokyo, Japan on 4 Decmber 2015.

15. Ratna, S. B., J. V. Ratnam, S. K. Behera, Fredolin T. Tangang, T. Yamagata (2015): Downscaling climate variability over Southeast Asia using WRF model. 12th Annual Meeting Asia Oceania Geosciences Society (AOGS 2015), Singapore, 2-7 August 2015. (link)

16. Ratna, S. B., J. V. Ratnam, S. K. Behera, T. Yamagata (2015): Simulating seasonal climate variability over South Africa using WRF model. 12th Annual Meeting Asia Oceania Geosciences Society (AOGS 2015), Singapore, 2-7 August 2015. (link)

17. Ratna, S. B.,  J. V. Ratnam, S. Behera, and T. Yamagata (2015): Downscaling Southeast Asia climate using a regional climate model. CMCC-JAMSTEC symposium on predictability and applicability of climate variations and change, held at the CMCC, Bologna, Italy during 16-18 March 2015. (link)

18. Ratna, S. B., A. Cherchi, S. Joseph, B. Abish, S. Masina (2014): Decreasing trend of the Indian summer monsoon rainfall and its relationship with the western Pacific Ocean. National Seminar on Impact of Climate Change Successes and Challenges in Ocean & Atmospheric Research (SCOAR-2014), held at the Andhra University, Visakhapatnam, 9-11 October 2014.

19. Ratna, S. B., A. Cherchi, and S. Masina  (2013): Indian Ocean warming and its fingerprint in the atmosphere. EU-INDIA INDO-MARECLIM workshop-II on Monsoon and Ocean Variability, Climate Change & Sea Level Variations, held at Bolgatty Palace & Island Resort, Kochi, India during 11-13 November 2013.

20. Ratna, S. B.,  S. Behera, J. V. Ratnam, T. Ndarana, H. Rautenbach, K. Takahashi and T. Yamagata (2013): Downscaling summer season climate variability over South Africa using WRF model. APL-SATREPS Workshop on the Predictability of Climate Variations and its Applications, held at the University of Tokyo, Tokyo, Japan during 1 March 2013.

21. Ratna, S. B., S. Behera, J. V. Ratnam, K. Takahasi and Toshio Yamagata, 2012: Extreme weather events associated with tropical-extratropical interactions. International conference on Future Directions for weather and climate research in the tropics, held at IIT Delhi, New Delhi during 3-5 December 2012.

22. Ratna, S. B.,  S. Behera, J. V. Ratnam, T. Ndarana, H. Rautenbach, K. Takahashi and T. Yamagata (2012): Simulation of extreme seasonal climate over South Africa using the high resolution Weather Research and Forecasting (WRF) model. AGU Chapman Conference on The Agulhas System and its Role in Changing Ocean Circulation, Climate, and Marine Ecosystem, held at the Spier Hotel, Stellenbosch, Western Cape, South Africa during 8–12 October 2012. (link)

23. Ratna, S. B., S. Behera, J. V. Ratnam, H. Rautenbach, T. Ndarana, K. Takahashi and T. Yamagata (2012): Downscaling extreme summer season rainfall over South Africa using the high resolution WRF model. South African Society for Atmospheric Sciences (SASAS-2012)  held at Cape Town, South Africa during 26-27 September 2012. (link)

24. Ratna, S. B., S. Behera, J. V. Ratnam, K. Takahasi and Toshio Yamagata, 2012: Influence of La Nina on extreme rainfall over southern Africa associated with tropical temperate troughs, Japan Geoscience Union (JpGU) meeting, held at the Makahari Messe, Chiba, Japan during 20-25 May, 2012. (link)

25. Ratna, S. B., J. V. Ratnam, S. Behera, K. Takahasi and Toshio Yamagata, 2012: Seasonal simulation of heavy rainfall events over southern Africa using a high‐resolution regional model: sensitivity to cumulus parameterization schemes, The 10th International Conference on Southern Hemisphere Meteorology and Oceanography (10ICSHMO), held at the Tjibaou Cultural Center,  Nouméa, New Caledonia during 23 to 27 April 2012. (link)

26. Ratna, S. B., S. Behera, J. V. Ratnam, K. Takahasi and Toshio Yamagata, 2012: Extreme weather events associated with tropical-extra tropical interaction over southern Africa and its temporal evolution, International Symposium on Climate Variations-From Basic Research to Rich Applications,  held at the University of Tokyo, Japan during 11-13 April, 2012. (link)

27. Ratna, S. B., S. Behera, Desmond Manatsa, K. Takahasi and Toshio Yamagata, 2012: Intraseasonal and interannual variability of summer rainfall over Limpopo, South Africa, SATREPS workshop on Climate and weather predictions and its application to the southern African region, held at JAMSTEC, Tokyo, Japan during 23 February, 2012.

28. Ratna, S. B., S. Behera, J. V. Ratnam, K. Takahasi and Toshio Yamagata, 2011:A Dynamical Index for Tropical Temperate trough over southern Africa and Southwest India Ocean, SATREPS Symposium on Climate Prediction and its Application in the southern African Region, held at the University of Tokyo, Japan during 20-21 October, 2011.(link)

29. Ratna, S. B, 2011: Dynamical Seasonal Simulation of Indian Summer Monsoon Circulation and Rainfall using an Atmospheric General Circulation Model, India-Japan Symposium on Global Challenges in Health and Environment, held at the Embassy of India, Tokyo, Japan on 7 October 2011. (link)

30. Ratna, S. B., J. V. Ratnam, S. Behera, K. Takahasi and Toshio Yamagata, 2011: Simulation of 2010/11 Summer Season Heavy Rainfall Events over Southern Africa Using WRF Model. Presented at the Annual conference on South African Society for Atmospheric Sciences (SASAS-2011) held at the Amanzingwe Hotel, Pretoria, South Africa during 22-23 September 2011. (link)

31. Ratna, S. B., J. V. Ratnam, S. Behera, K. Takahasi and Toshio Yamagata, 2011: Performance of the WRF Model in simulating the Tropical Temperate Troughs over southern Africa. Presented at the 12th Annual WRF Users' Workshop held at the National Centre for Atmospheric Research (NCAR), Boulder, USA during 20-24 June 2011.(link)

32. Ratna, S. B., J. V. Ratnam, S. Behera, K. Takahasi and Toshio Yamagata, 2010: Downscaling a weather event over South Africa using WRF Model. Presented at theSATREPS symposium on Climate Prediction and Information for the Society, The University of Aizu, Aizu, Japan during 16-18 December 2010. (link)

33. Ratna, S.B., M.Ashfaq and A.Kaginalkar, 2010: Numerical Simulation of Anomalous South Asian Summer Monsoon of 2009 using ICTP RegCM3. Presented at the  International conference on Asia Oceania Geosciences Society (AOGS-2010) Hyderabad, India during 5-9, July 2010. (link)

34. Ratna, S. B., 2009: Simulation of Indian Summer Monsoon Rainfall using NCEP T170L42 Atmospheric General Circulation Model. Presented at the Workshop on “High-Resolution Climate Modeling” held at the International Centre for Theoretical Physics (ICTP), Trieste, Italy during 10-14 August 2009. (link)

35. Ratna, S. B., M. Dalvi, B. K. Samal, A. Thomas, K. Sharma, S. Banerjee and A. Kaginalkar, 2009: Development of real-time weather information services for Kerala using high-resolution atmospheric model. Proceeding of the national workshop on “Climate and Development”, Kerala Agriculture University, Thiruvanathapuram, 281-292.

36. Ratna, S. B. and D.V.Bhaskar Rao, 2008: A comparison of the performance of different cumulus parameterization schemes in the prediction of a monsoon heavy rainfall event. Presented at the “95th Indian Science Congress” held at Andhra Univesrsity, Visakhapatnam during 3-7 January, 2008.

37. Ratna, S. B. and D.V.Bhaskar Rao, 2007: Simulation of Indian summer monsoon during July of the contrasting weak and good monsoon years of 2002 and 2003 using a regional climate model. Presented at the National Conference on “TROPMET-2007” held at Indian Meteorological Department/Barkatullah University, Bhopal during 17-19 December, 2007.

38. Ratna, S. B., 2007: Study of heavy rainfall events over west coast of India using a mesoscale model. Presented at UK-India Young Scientists Conference on Extreme Weather Events held at New Delhi, India 26-30 November 2007.

39. Ratna, S. B., 2007: Short range prediction of the rainfall during the onset phase and heavy rainfall events of the Indian southwest monsoon. Presented at the 4th KAGI 21 International summer school on “Active Geosphere Science” held at Institute Technology Bandung, Bandung, Indonesia during 22 July-4 August 2007.

40. Ratna, S. B., D. Hariprasad and D.V.Bhaskar Rao, 2007: Numerical prediction of the onset phase of the Indian southwest monsoon. Presented at the International conference on “Celebrating monsoon” held at IISc, Bangalore during 24-28 July 2007. (link)

41. Bhaskar Rao. D.V., D. Hariprasad, S. B. Ratna, 2007: Impact of data assimilation on mesoscale weather prediction. Presented at the workshop on “GPS Radio Occultation Technique” held at NARL, Gadanki during 19-20 April, 2007.

42. Bhaskar Rao. D.V., D. Hariprasad, S. B. Ratna, 2007: Mesoscale modelling of tropical cyclones and monsoon processes, Presented at National workshop on “Mesoscale Modeling of Atmospheric Processes”, Andhra University, Visakhapatnam during 29-31 January 2007.

43. Ratna, S. B, D. Hariprasad and D.V.Bhaskar Rao, 2006: On the Feasible Improvements in the Prediction of Monsoon Heavy Rainfall events with Four Dimensional Data Assimilation, Presented at national conference “TROPMET-2006”, Indian Institute of Tropical Meteorology, Pune during 21-23 November 2006. (link)

44. Hariprasad, D., S. B. Ratna and D.V.Bhaskar Rao, 2006: Importance of horizontal resolution and nested domains on movement and intensification of the Bay of Bengal Cyclone using High Resolution Mesoscale Model , Presented at national conference “TROPMET-2006”, Indian Institute of Tropical Meteorology, Pune during 21-23 November 2006. (link)

45. Hariprasad, D., S. B. Ratna and D.V.Bhaskar Rao, 2006: Impact of Horizontal Resolution on Intensification of the Bay of Bengal Cyclone using High Resolution Mesoscale Model , Presented at a national conference on Mathematical Analysis and its application in real world problems Berhampur University, Berhampur during 16-17 September 2006. 

46. Bhaskar Rao. D.V., D. Hariprasad, S. B. Ratna, 2006: Tropical cyclones over Bay of Bengal. Presented at workshop on Tsunamies,Cyclones and Floods at Eluru, 31 July-1 August 2006.

47. Bhaskar Rao. D.V., D. Hariprasad, S. B. Ratna, 2006: Monsoon Rainfall Variability over India - Atmospheric Teleconnections, Presented at a national conference NFEEG at Andhra University, Visakhapatnam, 30-31,May 2006.

48. Ratna, S. B., D. Hariprasad and D.V.Bhaskar Rao, 2006: Numerical prediction of the Heavy Rainfall Events during Armex-Phase I of the  summer  monsoon, 2002, Presented at ARMEX Workshop NIO, Goa,19-21, April 2006. (link)

49. Ratna, S. B., D. Hariprasad and D.V.Bhaskar Rao, 2006: Numerical prediction of the heavy rainfall event of 26 July 2005 over Mumbai: A case study using NCAR MM5. Presented at Workshop on Extreme Weather Events at CMMACS, Bangalore, 16-17, March 2006. (link)

50. Ratna, S. B., D. Hariprasad and D.V.Bhaskar Rao, 2006: Numerical prediction of the heavy rainfall event of 26 July 2005 over Mumbai (west coast of India): A case study using NCAR MM5. Presented at THORPEX/WCRP/ICTP Workshop on Organisation and Maintenance of Tropical Convection and the Madden Julian Oscillation, ICTP, Italy, 13-17, March 2006. (link)

51. Ratna, S. B, D. Hariprasad and D.V.Bhaskar Rao, 2006: Numerical prediction of the heaviest rainfall event (over Mumbai) during the southwest monsoon season of 2005. Presented at IMPA-2006 at IITD, 14-17, February 2006.

52. Hariprasad, D., S. B. Ratna and D.V.Bhaskar Rao, 2005: Numerical prediction of the development and intensification of the tropical cyclones over Bay of Bengal. Presented at National conference on “Tsunami and Other Natural Coastal Hazards” at Andhra University, Visakhapatnam, India. 7-9,November 2005.

53. Ratna, S. B, D. Hariprasad and D.V.Bhaskar Rao, 2005: Mumbai heavy rainfall on 26th July, 2005: A case study of the prediction. Presented at National conference on “Tsunami and Other Natural Coastal Hazards” at Andhra University, Visakhapatnam, India. 7-9, November 2005.

Student Lead Presentation

1. Sisodiya, S. S.,  S. B. Ratna,  S. Dutta (2022): Study Of Indian Summer Monsoon Variability Over Gujarat  (West Coast India) And Associated Large Scale Dynamics, at the national symposium TROPMET-2022 held in IISER, Bhopal during 29 November - 2 December 2022.

2. Sharma, T.,  S. B. Ratna,  D. S. Pai (2022): Reinvestigating the changing relationship between the Indian Summer Monsoon and ENSO in the recent decades, at the national symposium TROPMET-2022 held in IISER, Bhopal during 29 November - 2 December 2022.