1. Role of Rossby waves in the remote effects of the north Indian Ocean tropical disturbances.
- Author
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RATNAM, J. V., BEHERA, S. K., MASUMOTO, Y., and YAMAGATA, T.
- Subjects
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ROSSBY waves , *ATMOSPHERIC waves , *STORMS , *MONSOONS , *WEATHER forecasting - Abstract
Remote effects due to the tropical disturbances in the north Indian Ocean are investigated by analyzing long lasting (≥ 5 days) tropical disturbances, which reached at least the strength of tropical storms. The present analysis is carried out for both the pre-monsoon and post-monsoon periods. The spatial and temporal distribution of the Outgoing Long wave Radiation (OLR) during the pre-monsoon disturbances over the Bay of Bengal reveals several interesting features. Temporal distribution of the OLR anomalies shows that the intraseasonal oscillations play an important role in the formation of those disturbances. The spatial distribution of the OLR anomalies shows a dipole with negative OLR anomalies over the Bay and positive OLR anomalies over the Indonesian region. The atmospheric response to the negative OLR anomalies results in positive temperature anomalies over the northwest India, Pakistan, Afghanistan, Iran and Saudi Arabia, remote from the disturbance and the response to the positive anomalies causes slight increase in the sea surface temperature of the Arabian Sea. Negative OLR anomalies are also seen over the western Japan, due to the Rossby waves generated by the heating over the Bay of Bengal besides the enhancement of the so-called "Pacific-Japan" teleconnection pattern. However, the analysis shows that the post-monsoon disturbances over the Bay of Bengal and the disturbances formed over the Arabian Sea in both pre- and post-monsoon seasons do not develop remote teleconnections associated with the above type of Rossby wave mechanism. These results are significant for the short to medium range weather forecast over a wide range covering Japan, Pakistan, Afghanistan, Iran and Saudi Arabia. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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