Abstract
The summer monsoon onset over Kerala (MOK) marks the beginning of the rainy season for the country. Associated with the MOK, significant transitions of large scale atmospheric and oceanic circulation patterns are observed over the Asia-Pacific region. In this study, a new method for the objective identification of MOK, based on large scale circulation features and rainfall over Kerala, is discussed. Further, a set of empirical models based on the principal component regression (PCR) technique was developed for the prediction of the date of MOK by keeping in mind the IMD’s operational forecasting service requirements. Predictors for the models were derived using correlation analysis from the thermal, convective and circulation patterns. Only five predictors pertaining to the second half of April were used in the first model (Model-1) so that the prediction of MOK can be prepared by the end of April itself. The second model (Model-2) used four additional predictors pertaining up to the first half of May along with two predictors used in the Model-1 for update prediction at the end of the first half of May. To develop each of the PCR models, Principal Components Analysis (PCA) of the respective predictor data was carried out followed by regression analysis of first two principal components (PCs) with the date of MOK. Both these models showed good skill in predicting the date of MOK during the independent test period of 1997–2007. The root mean square error (RMSE) of the predictions from both the models during the independent test period was about four days which was nearly half the RMSE of the predictions based on climatology.
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References
Ananthakrishnan R and Soman M K 1988 The onset of southwest monsoon over Kerala for the period 1870–1990; Int. J. Climatol. 9 283–296.
Ananthakrishnan R and Soman M K 1991 Onset of southwest monsoon in 1990; Curr. Sci. 61 447–453.
Ananthakrishnan R, Acharya U R and Ramakrishnan A R 1967 On the criteria for declaring the onset of the southwest monsoon over Kerala; Forecasting Manual. FMU Report No. IV-18.1: 52, India Meteorological Department, Pune, India.
Ananthakrishnan R, Pathan J M and Aralikatti S S 1983 The onset phase of the southwest monsoon; Curr. Sci. 52 155–164.
Ananthakrishnan R, Srinivasan V, Ramakrishnan A R and Jambunathan R 1968 Synoptic features associated with onset of southwest monsoon over Kerala; Forecasting Manual Report No. IV-18.2, India Meteorological Department, Pune, India.
Fasullo J and Webster P J 2003 A hydrological definition of Indian monsoon onset and withdrawal; J. Climate 16 3200–3211.
Flatau M, Flatau P and Rudnick D 2001 The dynamics of double monsoon onsets; J. Climate 14 4130–4146.
Flatau M, Flatau P, Schmidt J and Kiladys G 2003 Delayed onset of the 2002 Indian monsoon; Geophys. Res. Lett. 30 1768.
Hsu H H, Terng C T and Chen C T 1999 Evolution of large-scale circulation heating during the first transition of Asian summer monsoon; J. Climate 12 793–810.
Joseph P V and Pillai P V 1988 40-day mode of equatorial trough for long range forecasting of Indian summer monsoon onset; Curr. Sci. 57 951–954.
Joseph P V, Eishcheid J K and Pyle R J 1994 Interannual variability of the onset of the Indian summer monsoon and its association with atmospheric features, El Niño and sea surface temperature anomalies; J. Climate 7 81–105.
Joseph P V, Sooraj K P and Rajan C K 2006 The summer monsoon onset over process over south Asia and an objective method for the date of monsoon onset over Kerala; Int. J. Climatol. 26 1871–1893.
Kaiser H F 1958 The varimax criterion for analytic rotation in factor analysis; Psychometrika 23 187–200.
Kalnay E et al 1996 The NCEP/NCAR re-analysis project; Bull. Am. Meteorol. Soc. 77 437–471.
Koteswaram P 1958 The Easterly Jet Stream in the Tropics; Tellus 10 43–57.
Koteswaram P 1960 The Asian summer monsoon and the general circulation over the tropics; In: Monsoons of the world, India Meteorological Department, New Delhi, 105–110.
Krishnamurti T N and Ramanathan Y 1982 Sensitivity of the Monsoon Onset to Differential Heating; J. Atmos. Sci. 39 1290–1306.
Kung E C and Sharif T A 1980 Regression forecasting of the onset of the India summer monsoon with antecedent upper air conditions; J. Appl. Meteorol. 19 370–380.
Kung E C and Sharif T A 1982 Long-range forecasting of the Indian summer monsoon onset rainfall with upper air conditions; J. Meteorol. Soc. Japan 60 672–681.
McBride J L and Nicholls N 1983 Seasonal relationships between Australian rainfall and the southern oscillation; Mon. Wea. Rev. 111 1998–2004.
Murakami T and Ding Y 1982 Wind and temperature changes over Eurasia during the early summer of 1979; J. Meteorol. Soc. Japan 60 183–196.
Nicholls N 1984 The stability of empirical long range forecast techniques: A case study; J. Appl. Meteorol. 23 143–147.
Pearce R P and Mohanty U C 1984 Onsets of the Asian Summer Monsoon 1979–82; J. Atmos. Sci. 41 1620–1639.
Rajeevan M, Guhathakurta P and Thapliyal V 2000 New models for long range forecasting of monsoon rainfall over northwest and peninsular India; Meteorol. Atmos. Phys. 73 211–225.
Rajeevan M and Dubey D P 1995 Long range prediction of monsoon onset over Kerala; Mausam 46 287–290.
Ramesh Kumar M R 2004 Forecasting of onset of southwest monsoon over Kerala coast using satellite data; IEEE Geosci. Remote Sensing Lett. 1(4) 265–267.
Rao C R 1964 The use and interpretation of principal component analysis in applied research; Sankhya (Indian Journal of Statistics) 26 329–358.
Rao Y P 1976 Southwest monsoon; Meteorological Monograph, Synoptic Meteorology No. 1/1976. India Meteorological Department, New Delhi.
Reddy S J 1977 Forecasting the onset of southwest monsoon over Kerala; Indian J. Meteorol. Hydrol. Geophys. 28 113–114.
Sikka D R and Gadgil S 1980 On the maximum cloud zone and the ITCZ over Indian longitudes during the southwest monsoon; Mon. Wea. Rev. 108 1840–1853.
Singh O P and Pai D S 1996 An oceanic model for the prediction of SW monsoon rainfall over India; Mausam 47 91–98.
Soman M K and Krishna Kumar K 1993 Space-time evolution of meteorological features associated with the onset of the Indian summer monsoon; Mon. Wea. Rev. 121 1177–1194.
Tanaka M 1992 Intraseasonal oscillation and the onset and retreat dates of the summer monsoon east, southeast Asia and the western Pacific region using GMS high cloud amount data; J. Meteorol. Soc. Japan 70 613–628.
Wang B and Lin Ho 2002 Rainy season of the Asian-Pacific summer monsoon; J. Climate 15 386–396.
Wang B and Wu R 1997 Peculiar temporal structure of the South China Sea summer monsoon; Adv. Atmos. Sci. 14 177–194.
Wang B, Lin Ho, Zhang Y and Lu M M 2004 Definition of South China Sea Monsoon Onset and Commencement of the East Asia Summer Monsoon; J. Climate 17 699–710.
Webster P J, Magana V O, Palmer T N, Shukla J, Tomas R A, Yanai M and Yasunari T 1998 Monsoons: Processes, predictability, and the prospects for prediction; J. Geophys. Res. 103 14,451–14,510.
Yin M T 1949 A synoptic-aerologic study of the onset of the summer monsoon over India and Burma; J. Meteorol. 6 364–400.
Zeng X and Lu E 2004 Globally unified monsoon onset and retreat indexes; J. Climate 17 2241–2248.
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Pai, D.S., Nair, R.M. Summer monsoon onset over Kerala: New definition and prediction. J Earth Syst Sci 118, 123–135 (2009). https://doi.org/10.1007/s12040-009-0020-y
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DOI: https://doi.org/10.1007/s12040-009-0020-y