r . K. DAS, O. A. GEORGE and R. J ,\)IBlmATHAXJld_ olo<jrol O.JJiu , PCXJ1IG

(ReceiV<'l1 13 J uly 1973)

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IndIan Journal of

M ET EO RO LO GY & GEOPHYSICS

Cyclones and depressions of I972-Bay of Bengaland Arabian Sea

OCTOBER 1973

Vol. 24 No . 4

551·515 (267) " 1972"

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1. IntroduetloD

Seven cyclonic storm. and nine depressionsformed in the Bay of Bengal ami the Arabisn Seaduring the year 1972. Two depressions also deve­loped over land arc,... one over Ganget ic WestBengal ami the other over BUIILr P lateau. Oftho seven cyclonic storms, six formed in the Bayof Bengal (five of them of severe intensity) and oneof severe intensity in the Arabian Sea. Of thenine depressions, six developed during themonsoon seaso n. The tracks of these storms anddepre... ions are shown in Fig. I and th eir monthlydist ribut ion in Table I.

The main fe.atures of this year's cyclonic dis­t urbances were :

(i) No cyclonic storm struck the west COlL. t ofI ndia.

(i.) South Orissa and Tamil Nadu were themain targct.q of cyclones. T~e t wo severe cycloneswhieh hit south Orissa and adj oining northAnclhra in September , and the severe cyclonewhich hit Tamil ~adu in December, caused consi­derable damage to property. But the 1088 to life \VIl'I

negligible as warnings were i sued well in timeand t imely precautionary measures were takenby the State Governments. Storm surge..varying from I to 3 metres high were reporteda long Orissa coast in association with the severeBaruva cyclone of 10Septemher.

(iii) The depressions and low pressure areaswhich moved across the plains of north Indiaduring the monsoon did not cause any seriousfloods th is year.

A brief history of the cyclones and depressions,together with important featu res ....socinted withthem, is onumorated in the following paragraphsin chronological order.

2. Bal 01 B, lIP\

2. I. Severe (JIJdonic stormof 7-11 A prilA low pressure area developed over south

Andaman Sca and adjoining southeast Bay on the6th. It concentrated into a depression on themorning of t he 7t1t near 9'N, 91'E. ) Io\'ing north­west , it intensified into n cyclonic storm of nar rowcore the same evening near 9 .1;' N, 90.5' E. Thenmoving practically northwards, it, became severeon thc evening of 8th with it... cent re near II. 5'N,90.0'E. Continuing to move northwareIs, itweakened into a depression on t.ho morning of11th near (jON, 91'E and dissipated tbe sameevening over east cent ral and adjoining north­east Bay. The weakening of the storm was pro­bably due to the storm having moved into a rezionof lower sea surface temperature. Somo ships re­ported sea surface temperatu res between 28"0 to31°0 in the south Bay, while a ship in north andadjoining C38t cent ral Ba)' report ed sea surfacetemperature of 27°0. Advection of cold air fromsouth of the westerly jet maximum above 200mb, could have also contri buted to the cooling ofthe storm at top levels.

This system caused widespread rain in the BayIslands from 7th to 10th, with seattered heavvfalls on the Sth and 9th. Oar Y1cohar report eda heavy fall of 10 cm of rain on th e 8th: while ontho 9th. Ma)'a Bandar reported 9 em, LongIsland 8 cru and Port Blair 7 cm. No damagewas caused by this cyclone.

Thi. system could 'not be detected on thesynoptie charts with availahte data . It w de-tooted and tracked only wi th the aid of tollitepictures and aircraft reconnaissance reports.

The U.S. Air Force rocounsh sanco aircraftSWAN 01 which flew into tho storm on tho 9thgave the centre of tho storm at 1300 G) IT as

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