Main Article Content
This study investigated the correlation coefficient between sea surface temperature (SST) and the standard precipitation Index (SPI) at stations in south of Vietnam. The data included in this survey are the precipitation of 47 stations in South Vietnam and the field of SST from the NCEP/NCAR Reanalysis for the period between 1979 and 2019. The results show that with a single region, SST in the Niño 3.4 region has the best relationship with SPI in the study area. Using multiple correlation analysis, this study found a region between 115 oE and 130oE and latitude from 15 oS to 25 oN, combined with the Niño 3.4 region SST they create a pair that has the best relationship with SPI in the study area. Based on an assessment of the critical value of the Pearson correlation coefficient corresponding to the significance level of 99%, this pair had a good relationship with SPI between October and May of the following year. By conducting a partial correlation analysis when removing the role of Niño 3.4 also showed that SST in the Bien Dong also plays an important role in the fluctuation of SPI in South Vietnam.
 N. V. Thang, M. V. Khiem, N. D. Mau, T. D. Tri, Determining Drought Citeria for the South Central Region, Vietnam Journal of Hydrometeorology, Vol. 639, 2014, pp. 49-55 (in Vietnamese).
 V. V. Thang, N. T. Hieu, N. V. Thang, N. V. Hiep, P. T. T. Huong, N. T. Lan, Effects of ENSO on Autumn Rainfall in Central Vietnam, Adv. Meteorol., Vol. 2015, 2015, pp. 1-12, https://doi.org/10.1155/2015/264373.
 C. F. Ropelewski, M. S. Halpert, Global and Regional Scale Precipitation Patterns Associated with the El Niño/Southern Oscillation, Mon. Weath. Rev., Vol. 115, 1987, pp. 1606-1626, https://doi.org/10.1175/15200493(1987)115<1606: GARSPP>2.0.CO;2.
 C. F. Ropelewski, M. S. Halpert, Precipitation Patterns Associated with the High Index Phase of the Southern Oscillation, J. Climate, Vol. 2, 1989, pp. 268-284, https://doi.org/10.1175/1520-0442 (1989)002<0268:PPAWTH>2.0.CO;2.
 C. F. Ropelewski, M. S. Halpert, Quantifying Southern Oscillation Precipitation Relationships,
J. Climate, Vol. 9, 1996, pp. 1043-1059, https://doi.org/ 10.1175/1520-0442(1996) 009<1043: QSOPR>2.0.CO;2.
 M. S. Halpert, C. F. Ropelewski, Surface Temperature Patterns Associated with the Southern Oscillation, J. Climate, Vol. 5, 1992, pp. 577–593, https://doi.org/10.1175/1520-0442(1992)005<0577: STPAWT>2.0.CO;2.
 H. C. Y. Lam, A. Haines, G. McGregor, E. Y. Y. Chan, S. Hajat, Time-Series Study of Associations Between Rates of People Affected by Disasters and the El Niño Southern Oscillation (ENSO) Cycle, Int. J. Environ. Res. Public Health, Vol. 16, 2019, pp. 3146, https://doi.org/10.3390/ijerph16173146.
 J. Ju, J. Slingo, The Asian Summer Monsoon and ENSO, Q. J. R. Meteorol. Soc., Vol. 121, No. 525, 1995, pp. 1133-1168, https://doi.org/10.1002/qj.49712152509.
 P. J. Webster, S. Yang, Monsoon and ENSO: Selectively Interactive Systems, Q. J. R. Meteorol. Soc., Vol. 118, No. 507, 1992, pp. 877-926.
 W. Zhou, J. C. L. Chan, ENSO and the South China Sea Summer Monsoon Onset, Int. J. Climatol., Vol. 27, No. 2, 2007, pp.157-167,
 T. Q. Duc, N. P. Thao, T. T. Long, P. V. Tan,
C. T. T. Huong, N. V. Hiep, Investigation of Drought Characteristics Across Vietnam During Period 1980-2018 using SPI and SPEI Drought Indices, VNU Journal of Science: Earth and Environmental Science, Vol. 38, No. 1, 2012, pp. 71-84 (in Vietnamese).
 K. Ashok, El Niño Modoki and Its Teleconnection, J. Geophys. Res., Vol. 112, 2017, pp. C11007, https://doi.org/10.1029/2006JC003798.
 A. D. Magee, C. D. V. Kidd, H. J. Diamondb,
A. S. Kiem, Inﬂuence of ENSO, ENSO Modoki, and the IPO on Tropical Cyclogenesis: a Spatial Analysis of the Southwest Pacifc Region, Int. J. Climatol, Vol. 37, 2017, pp. 1118-1137, https://doi.org/10.1002/joc.5070.
 A. S. Taschetto, M. H. England, El Niño Modoki Impacts on Australian Rainfall, J. Climate,
Vol. 22, 2009, pp. 3167-3174.
 G. Li, B. Ren, C. Yang, J. Zheng, Indices of El Niño and El Niño Modoki: An Improved El Niño Modoki Index, Adv. Atmos. Sci., Vol. 27, 2010, pp. 1210-1220.
 H. I. Jeong, J. B. Ahn, A New Method to Classify ENSO Events Into Eastern and Central Pacifc Types, Int. J. Climatol, Vol. 37, pp. 2017,
pp. 2193-2199, https://doi.org/10.1002/joc.4813.
 H. L. Ren, Statistical Predictability of Niño Indices for Two Types of ENSO, Climate Dynamics,
Vol. 52, 2019, pp. 5361-5382, https://doi.org/10.1007/s00382-018-4453-3.
 H. Paek, J. Yu, F. Zheng, Impacts of ENSO Diversity on the Western Pacific and North Pacific Subtropical Highs During Boreal Summer, Climate Dynamics, Vol. 52, 2019, pp. 7153-7172, https://doi.org//10.1007/s00382-016-3288-z.
 H. Weng, S. K. Behera, T. Yamagata, Anomalous Winter Climate Conditions in the Pacific Rim During Recent El Niño Modoki and El Niño Events, Climate Dyn., Vol. 32, 2009, pp. 663-674.
 H. Y. Kao, J. Y. Yu, Contrasting Eastern-Pacific and Central-Pacific Types of ENSO, J. Climate, Vol. 22, 2009, pp. 615-663.
 J. Feng, J. Li, Influence of El Niño Modoki on Spring Rainfall over South China, J. Geophys. Res. Atmos., Vol. 116, 2011, pp. D13102, https://doi.org/10.1029/2010JD015160.
 W. J. Zhang, F. F. Jin, J. Li, H. L. Ren, Contrasting Impacts of Two Types of El Niño Over the Western North Pacific During Boreal Autumn, J. Meteor. Soc. Japan, Vol. 89, 2011, pp. 563-569, https://doi.org/ 10.2151/jmsj.2011-510.
 X. Wang, C. Guan, R. X. Huang, W. Tan, L. Wang, The Roles of Tropical and Subtropical Wind Stress Anomalies in the El Niño Modoki Onset, Climate Dynamics, Vol. 52, 2019, pp. 6585-6597, https://doi.org/10.1007/s00382-018-4534-3.
 Y. Yuan, S. Yang, Impacts of Different Types of El Niño on the East Asian Climate: Focus on ENSO Cycles, Journal of Climate, Vol. 25, 2012,
 L. V. Viet, Development of a New ENSO Index to Assess the Effects of ENSO on Temperature over Southern Vietnam, Theor Appl Climatol, Vol. 144, 2021, pp. 1119-1129, https://doi.org/10.1007/s00704-021-03591-3.
 M. K. Lien, T. H. Thai, H. V. Dai, D. N. Diep,
T. D. B. Trung, Characterristic of Droughts in the Mekong River Delta, Vietnam Journal of Hydrometeorology, Vol. 665, 2016, pp. 1-5
 V. A. Tuan, V. T. Hang, T. H. Duong, The Characterristics and Trends of Meteorological Drought in Central Highlands, Vietnam Journal of Hydrometeorology, Vol. 699, 2019, pp. 50-57
 World Meteorological Organization (WMO) and Global Water SPI artnership (GWP), Handbook of Drought Indicators and Indices, Geneva, Switzerland, 2016.
 N. V. Thang, M. V. Khiem, The Assessment
and Projection of the Dry Condition for the Mekong River Delta by Using the SPI, Vietnam Journal of Hydrometeorology, Vol. 678, 2017, pp. 1-9
 V. T. Hang, T. T. T. Ha, Comparision of Some Drought in Climatic Sub-regions in Vietnam, VNU Journal of Science: Natural Sciences and Technology, Vol. 29, 2013, pp. 51-57 (in Vietnamese).
 T. B. Mckee, N. J. Doesken, J. Kleist, The Relationship of Drought Frequency and Duration to Time Scale, The Eighth Confrence on Applied Climatology, American Meteorological Society: Boston, 1993, pp. 179-184.