It is a pleasure to thank Prof. S. Manabe for his great encouragement, keen interest, and careful review of this paper. His comments and suggestions have greatly helped us in improving the manuscript. We would like to acknowledge Prof. T. Yasunari for very useful discussions. We are also thankful to the two anonymous referees for providing helpful reviews. This work was carried out when one of the authors (RK) was on a study leave from the Indian Institute of Tropical Meteorology. RK would like to thank Dr. G. B. Pant, director, IITM and Drs. V. Satyan, and M. K. Soman, IITM, for enabling his visit to FRSGC, Japan. Thanks are due to Dr. R. Suzuki for introducing the GMT graphics software. The user-friendliness of the GrADS graphics software developed by Dr. Brian Doty, COLA, is also gratefully acknowledged.
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