プロフィール

専門

研究業績

査読有り（JAMSTECでの成果）

Ingo Richter, Jayanthi V Ratnam, Patrick Martineau, Pascal Oettli, Takeshi Doi, Tomomichi Ogata, Takahito Kataoka, François Counillon. A Simple Statistical Postprocessing Scheme for Enhancing the Skill of Seasonal SST Predictions in the Tropics. MONTHLY WEATHER REVIEW, 2024, 152, 4, doi: 10.1175/MWR-D-23-0266.1
Micheal T. Pillay, Noboru Minakawa, Yoonhee Kim, Nyakallo Kgalane, Jayanthi V. Ratnam, Swadhin K. Behera, Masahiro Hashizume & Neville Sweijd. Utilizing a novel high-resolution malaria dataset for climate-informed predictions with a deep learning transformer model. Scientific Reports, 2023, 13, 23091, doi: 10.1038/s41598-023-50176-3
J. V. Ratnam, Swadhin K Behera, Masami Nonaka, Patrick Matineau, Kalpesh Patil. Predicting maximum temperatures over India 10-days ahead using machine learning models. Scientific Reports, 2023, 13, doi: 10.1038/s41598-023-44286-1
Patil Kalpesh Ravindra, Doi Takeshi, Jayanthi Venkata Ratnam and Behera Swadhin. Deep learning for skillful long-lead ENSO forecasts. Frontiers in Climate, 2023, 4, p. 1-18, doi: 10.3389/fclim.2022.1058677
J.V. Ratnam, Takeshi Doi, Ingo Richter, Pascal Oettli, Masami Nonaka and Swadhin K. Behera. Using Selected Members of a Large Ensemble to Improve Prediction of Surface Air Temperature Anomalies Over Japan in the Winter Months From Mid-Autumn. Frontiers in Climate, 2022, 4, doi: 10.3389/fclim.2022.919084
J. V. Ratnam, Masami Nonaka, and Swadhin K. Behera. Winter Surface Air Temperature Prediction over Japan Using Artificial Neural Networks. WEATHER AND FORECASTING, 2021, 36, 4, p. 1343-1356, doi: 10.1175/WAF-D-20-0218.1
J.V. Ratnam, Takeshi Doi, Yushi Morioka, Pascal Oettli, Masami Nonaka, Swadhin K. Beheera. Improving predictions of surface air temperature anomalies over Japan by Selective Ensemble Mean technique. WEATHER AND FORECASTING, 2020, 36, 1, doi: 10.1175/WAF-D-20-0109.1
M. Pal, R. Maity, J.V. Ratnam, M. Nonaka, S.K. Behera. Long-lead Prediction of ENSO Modoki Index using Machine Learning algorithms. Scientific Reports, 2020, 10, doi: 10.1038/s41598-019-57183-3
Rajib Maity, Kironmala Chanda, Riya Dutta, J. V. Ratnam, Masami Nonaka, Swadhin Behera. Contrasting features of hydroclimatic teleconnections and the predictability of seasonal rainfall over east and west Japan. METEOROLOGICAL APPLICATIONS, 2020, 27, 1, doi: 10.1002/met.1881
J.V. Ratnam, H.A. Dijkstra, S.K. Behera. A machine learning based prediction system for the Indian Ocean Dipole. Scientific Reports, 2020, 10, doi: 10.1038/s41598-019-57162-8
Yoonhee Kim, J. V. Ratnam, Takeshi Doi, Yushi Morioka, Swadhin Behera, Ataru Tsuzuki, Noboru Minakawa, Neville Sweijd, Philip Kruger, Rajendra Maharaj, Chisato Chrissy Imai, Chris Fook Sheng Ng, Yeonseung Chung and Masahiro Hashizume. Malaria predictions based on seasonal climate forecasts in South Africa: A time series distributed lag nonlinear model. Scientific Reports, 2019, 9, doi: 10.1038/s41598-019-53838-3
J. V. Ratnam, H. A. Dijkstra, Takeshi Doi, Yushi Morioka, Masami Nonaka and Swadhin K. Behera. Improving seasonal forecasts of air temperature using a genetic algorithm. Scientific Reports, 2019, 9, doi: 10.1038/s41598-019-49281-z
J.V. Ratnam, Takeshi Doi, Swadhin Behera. Improving austral summer precipitation forecasts of SINTEX‐F2 coupled ocean-atmosphere general circulation model over southern Africa by simple bias correction techniques. Atmospheric Science Letters, 2019, 20, 3, doi: 10.1002/asl.885
J.V. Ratnam, Takeshi Doi, Willem A. Landman, Swadhin K. Behera. Seasonal forecasting of onset of summer rains over South Africa. Journal of Applied Meteorology and Climatology, 2018, 57, 12, p. 2697-2711, doi: 10.1175/JAMC-D-18-0067.1
Behera, S. K., Y. Morioka, T. Ikeda, T. Doi, J. Ratnam, M. Nonaka, A. Tsuzuki, C. Imai, Y. Kim, M. Hashizume, S. Iwami, P. Kruger, R. Maharaj, N. Sweijd and N. Minakawa. Malaria incidences in South Africa linked to a climate mode in southwestern Indian Ocean. Environmental Development, 2018, 27, p. 47-57, doi: 10.1016/j.envdev.2018.07.002
Swadhin K. Behera, J. V. Ratnam. Quasi-asymmetric response of the Indian summer monsoon rainfall to opposite phases of the IOD. Scientific Reports, 2018, 8, doi: 10.1038/s41598-017-18396-6
J. V. Ratnam, Swadhin K. Behera, R. Krishnan, Takeshi Doi, Satyaban B. Ratna. Sensitivity of Indian summer monsoon simulation to physical parameterization schemes in the WRF model. CLIMATE RESEARCH, 2017, 74, 1, p. 43-66, doi: https://doi.org/10.3354/cr01484
Satyaban B. Ratna, J.V. Ratnam, Swadhin K. Behera, Annalisa Cherchib, Wanqiu Wangc, Toshio Yamagata. The unusual wet summer (July) of 2014 in Southern Europe. Atmospheric Research, 2017, 189, p. 61-68, doi: http://dx.doi.org/10.1016/j.atmosres.2017.01.017
J.V.Ratnam, Takeshi Doi and Swadhin K. Behera. Dynamical downscaling of SINTEX-F2v CGCM seasonal retrospective austral summer forecasts over Australia. Journal of Climate, 2017, doi: http://dx.doi.org/10.1175/JCLI-D-16-0585.1
Satyaban B. Ratna, J. V. Ratnam, S. K. Behera, Fredolin T. Tangang, T. Yamagata. Validation of the WRF regional climate model over the subregions of Southeast Asia: climatology and interannual variability. Climate Research, 2016, doi: doi: 10.3354/cr01445
J. V. Ratnam, Swadhin K. Behera, H. Annamalai, Satyaban B. Ratna, M. Rajeevan & Toshio Yamagata. ENSO's far reaching connection to Indian cold waves. Scientific Reports, 2016, 6, 37657, doi: 10.1038/srep37657
J.V.Ratnam, Swadhin K. Behera, Satyaban B Ratna, M. Rajeevan and Toshio Yamagata. Anatomy of Indian heatwaves. Scientific Reports, 2016, 6, 24395, doi: 10.1038/srep24395
J.V.Ratnam, Swadhin K. Behera, Takeshi Doi, Satyaban B. Ratna and Willem A. Landman. Improvements to the WRF seasonal hindcasts over South Africa by bias correcting the driving SINTEX-F2v CGCM fields. Journal of Climate, 2016, doi: http://dx.doi.org/10.1175/JCLI-D-15-0435.1
J. V. Ratnam, Yushi Morioka, Swadhin K. Behera, Toshio Yamagata. A model study of regional air-sea interaction in the austral summer precipitation over southern Africa. Journal of Geophysical Research Atmospheres, 2015, doi: 10.1002/2014JD022154
Jaynathi Venkata Ratnam, Swadhin K. Behera, Toshio Yamagata. Role of Cross-Equatorial Waves in Maintaining Long Periods of Low Convective Activity over Southern Africa. Journal of the Atmospheric Sciences, 2015, 72, 2, p. 682-692, doi: 10.1175/JAS-D-14-0063.1
JAYANTHI RATNAM VENKATA , BEHERA SWADHIN K. , MASUMOTO YUKIO , YAMAGATA TOSHIO. Remote effects of El Nino and Modoki events on the Austral Summer Precipitation of Southern Africa. Journal of Climate, 2014, doi: 10.1175/JCLI-D-13-00431.1
Sahu Netrananda , BEHERA SWADHIN K, JAYANTHI RATNAM VENKATA, Valmir Da Silva Roberto , Parhi Pradipta , Duan Welli , Takara Kaoru , Singh R.B. , YAMAGATA TOSHIO. El Nino Modoki connection to extremely-low streamflow of the Paranaiba River in Brazil. Climate Dynamics, 2013, doi: 10.1007/s00382-013-2006-3
Satyaban B. Ratna, J. V. Ratnam, S. K. Behera, C. J. deW. Rautenbach, T. Ndarana, K. Takahashi, T. Yamagata. Performance assessment of three convective parameterization schemes in WRF for downscaling summer rainfall over South Africa. Climate Dynamics, 2013, 42, p. 2931-2953, doi: DOI 10.1007/s00382-013-1918-2
Ratna Satyaban Bishoyi , JAYANTHI RATNAM VENKATA , BEHERA SWADHIN K. , Rautenbach C.J.deW , Ndarana T. , Takahashi Keiko , YAMAGATA TOSHIO. Performance assessment of three convective parameterization schemes in WRF for downscaling summer rainfall over South Africa. Climate Dynamics, 2013, doi: 10.1007/s00382-013-1918-2
Yushi Morioka, Ratnam Venkata Jayanthi, Wataru Sasaki, Yukio Masumoto. Generation mechanism of the South Pacific subtropical dipole. Journal of Climate, 2013, 26, 16, p. 6033-6045, doi: 10.1175/JCLI-D-12-00648.1
Ratnam, J., S. Behera, S. Ratna, H. Rautenbach, C. Lennard, J. Luo, Y. Masumoto, K. Takahashi, and T. Yamagata. Dynamical downscaling of austral summer climate forecasts over southern Africa using a regional coupled model. Journal of Climate, 2013
Satyaban B. Ratna; Swadhin Behera; J. Venkata Ratnam; Keiko Takahashi; Toshio Yamagata. An index for tropical temperate troughs over southern Africa. Climate Dynamics, 2012, 41, 2, p. 421-441, doi: 10.1007/s00382-012-1540-8
Swadhin Behera, Jayanthi V. Ratnam, Yukio Masumoto, Toshio Yamagata. Origin of Extreme Summers in Europe: The Indo-Pacific Connection.. Climate Dynamics, 2012, p. 1-14, doi: 10.1007/s00382-012-1524-8
Ratnam, J. V., S. K. Behera, Y. Masumoto, T. Yamagata. Role of Rossby waves in the remote effects of the north Indian Ocean tropical disturbance. Monthly Weather Review, 2012, 140, 11, p. 3620-3633, doi: 10.1175/MWR-D-12-0027.1
J. V. Ratnam, S. K. Behera, Y. Masumoto, K. Takahashi, T. Yamagata. A simple regional coupled model experiment for summer-time climate simulation over southern Africa. Climate Dynamics, 2011, doi: DOI: 10.1007/s00382-011-1190-2
J. V. Ratnam, S. K. Behera, Y. Masumoto, K. Takahashi, T. Yamagata. Anomalous climatic conditions associated with the El Nino Modoki during boreal winter of 2009. Climate Dynamics, 2011, p. -011-1108-z, doi: 10.1007/s00382
Pacific Ocean origin for the 2009 Indian summer monsoon failure. Geophysical Research Letters, 2010, 37, L07807, doi: 10.1029/2010GL042798