Pham Thanh Ha, Phan Van Van Tan

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In this study, a new approach to selecting the Rainy Season Onset Date (hereafter denoted as RSOD) criteria is proposed and applied for Central Highlands and Southern Vietnam based on daily rainfall station data from 1979 to 2015. This approach bases on the similarity between station-based RSODs and regional-scale RSOD signal, obtained by applying Multi variable Principal Component Analysis (MPCA). The results show that these selected criteria can capture reasonably the heterogeneity of the start of the rainy season on both regional- and local-scale. The determined RSODs for the Central Highlands and the South are consistent with previous studies. It suggests the application potential of this approach in objectively determining the suitable RSOD criteria for each station (local-scale) in other regions.


Keywords: Rainy season onset date, Central Highlands, Southern, Vietnam.


[1] P. T. Ha, N. D. Thanh, J. Matsumoto, P. V. Tan, V. V. Hoa, Rainfall Trends in Vietnam and their Associations with Tropical Cyclones during 1979–2019, SOLA, 2020,
[2] R. D. Stern, M. D. Dennett, D. J. Garbutt, The Start of the Rains in West Africa, Journal of Climatology, Vol. 1, No. 1, 1981, pp. 59-68.
[3] M. V. K. Sivakumar, Predicting Rainy Season Potential from the Onset of Rains in Southern Sahelian and Sudanian Climatic Zones of West Africa, Agricultural and Forest Meteorology, Vol. 42, No. 4, 1988, pp. 295-305.
[4] J. B. Omotosho, Long-range Prediction of the Onset and End of the Rainy Season in The West African Sahel, International Journal of Climatology, Vol. 12, No. 4, 1992, pp. 369-382,
[5] V. Moron, A. W. Robertson, R. Boer, Spatial Coherence and Seasonal Predictability of Monsoon Onset over Indonesia, Journal of Climate, Vol. 22, No. 3, 2009, pp. 840-850,
[6] B. Liebmann, J. A. Marengo, Interannual Variability of the Rainy Season and Rainfall in the Brazilian Amazon Basin, Journal of Climate,
Vol. 14, No. 22, 2001, pp. 4308-4318.
[7] B. Liebmann, S. J. Camargo, A. Seth, J. A. Marengo, L. M. V. Carvalho, D. Allured, R. Fu, C. S. Vera, Onset and End of the Rainy Season in South America in Observations and The ECHAM 4.5 Atmospheric General Circulation Model, Journal of Climate, Vol. 20, No. 10, 2007, pp. 2037-2050.
[8] C. M. Dunning, E. C. L Black, R. P. Allan, The Onset and Cessation of Seasonal Rainfall over Africa, Journal of Geophysical Research-Atmospheres, Vol. 121, No. 19, 2016, pp. 11405-11424.
[9] R. J. Bombardi, V. Moron, J. S. Goodnight, A Review Detection, Variability, and Predictability of Monsoon Onset and Withdrawal Dates, Int J Climatol, Vol. 40, 2020, pp. 641-667,
[10] B. Wang, LinHo, Rainy Season of the Asian–Pacific Summer Monsoon, Journal of Climate, Vol. 15, No. 4, 2002, pp. 386-398.
[11] L. S. Seregina, A. H. Fink, R. van der Linden, N. A. Elagib, J. G. Pinto, A New and Flexible Rainy Season Definition: Validation for the Greater Horn of Africa and Application to Rainfall Trends, Int J Climatol., Vol. 39, 2019, pp. 989-1012,
[12] G. J. Holland, Interannual Variability of the Australian Summer Monsoon at Darwin: 1952-82, Monthly Weather Review, Vol. 114, No. 3, 1986, pp. 594-604,<0594:IVOTAS>2.0.CO;2.
[13] H. H. Hendon, B. Liebmann, A Composite Study of Onset of the Australian Summer Monsoon, Journal of the Atmospheric Sciences, Vol. 47, No. 18, 1990, pp. 2227-2240,<2227:ACSOOO>2.0.CO;2.
[14] C. Li, M. Yanai, The Onset and Interannual Variability of the Asian Summer Monsoon in Relation to Land-Sea Thermal Contrast, Journal of Climate, Vol. 9, No. 2, 1996, pp. 358-375,<0358:TOAIVO>2.0.CO;2.
[15] J. Mao, J. C. L Chan, G. Wu, 2004, Relationship between the Onset of the South China Sea Summer Monsoon and Structure of the Asian Subtropical Anticyclone, Journal of the Meteorological Society of Japan, Vol. 82, No. 3, 2004, pp. 845-859,
[16] N. D. Quang, J. Renwick, J. McGregor, Variations of Monsoon Rainfall: a Simple Unified Index, Geophysical Research Letters, Vol. 41, No. 2, 2014, pp. 575-581,
[17] N. D. Ngu, N. T. Hieu, Vietnam Climate and Climate Resources, Science and Technics Publishing House, Hanoi, 2013 (in Vietnamese).
[18] N. L. Dzung, J. Matsumoto, N. D. Thanh, Climatological Onset Date of Summer Monsoon in Vietnam, International Journal of Climatology, Vol. 34, No. 11, 2014, pp. 3237-3250,
[19] N. L. Dzung, J. Matsumoto, Delayed Withdrawal of the Autumn Rainy Season over Central Vietnam in Recent Decades, Int. J. Climatol., Published online in Wiley Online Library, 2015,
[20] N. L. Dzung, J. Matsumoto, N. D. Thanh, Onset of the Rainy Seasons in the Eastern Indochina Peninsula, J. Clim, Vol. 28, 2015, pp. 5645-5666
[21] N. T. Huong, N. D. Thanh, N. H. Hanh, P. Baker, P. V. Tan, A Distinction between Summer Rainy Season and Summer Monsoon Season over the Central Highlands of Vietnam, Theoretical and Applied Climatology, Vol. 132, No. 3-4, 2018, pp. 1237-1246,
[22] P. T. Ha, R. van der Linden, N. D. Thanh, N. D. Quang, A. H. Fink, P. V. Tan, Predictability of the Rainy Season Onset Date in Central Highlands of Vietnam, Int J Climatol, Vol. 40, 2019, pp. 3072-3086,
[23] N. H. Dien, T. C. Minh, Duration and Correlation between Rainfall and the Length of Summer Monsoon over Vietnam Region, Final report of Project Number: QT 98-13, VNU University, 2000, (in Vietnamese).
[24] P. V. Tan, P. T. Ha, N. D. Quang, N. V. Hiep, N. D. Thanh, Change in Onset Date of Rainy Season in Central Highlands and Predictability, the VNU Journal of Science: Earth and Eniviromental Sciences, Vol. 32, No. 3S, 2016, pp. 1-18.
[25] D. Wilks, Statistical Methods in the Atmospheric Sciences, Cambridge, MA: Academic press, 2016
[26] P. K. Sen, Estimates of the Regression Coefficient Based on Kendall’s Tau, Journal of the American Statistical Association, Vol. 63, No. 324, 1968, pp. 1379-1389.
[27] M. G. Kendall, Rank Correlation Methods, Charles Griffin, London, 1975.
[28] N. D. Thanh, P. V. Tan, Non-parametric Test for Trend Detection of Some Meteorological Elements for the Period 1961-2007, VNU Journal of Science, Natural Sciences and Technology, Vol. 28, No. 3S, 2012, pp. 129-135 (in Vietnamese).
[29] Y. Zhang, T. Li, B. Wang, Onset of the Summer Monsoon over the Indochina Peninsula: Climatology and Interannual Variations, Int. J. Climatol., Vol. 15, No. 22, 2002, pp. 3206-3221.
[30] P. X. Thanh, B. Fontaine, N. Philippon, Onset of the Summer Monsoon over the Southern Vietnam and its Predictability, Theor Appl Climatol, Vol. 99, 2010, pp. 105-113,
[31] Y. Kajikawa, T. Yasunari, S. Yoshida, H. Fujinami, Advanced Asian Summer Monsoon Onset in Recent Decades, Geophysical Research Letters, Vol. 39, No. 3, 2012,