Mausam, (1985), 36,4, 405-112

5) \ ' 511.62 : 551.553.2 1 : 551. 51

Energetics of theEnergy terms and

monsoon circulation over southenergy transformation terms

Asia -II :

S. RAJAMA NI

Indian Ins titute 0/ Tropical M eteorology . Pune

iReceived 18 April 1983)

.." - ..r,l"T~ offi if .,~ i ' 19 63 if t(" ~~ sn:n: "" """!" '1M 'IT nr'1~T f~f¥R ')'1'1 ll"Trf"q'i 'lit""'"!if...- ""li "'" m qf"" ; .'it if """F,"" "" '"""''' . " >iru "" if f.f.1lr qar 1PITt li~ ''i ,arerf",,, \j~'1 i> J;;rr-f'lllA..-r illClq-'!'i'q "f..,<:fi.;" '" f<, a[ 'flIr ~ I " , i> >(R ill',;r-~ f'larfiarT-l-..' qr",,';-om ~'11i1 <To -1M f'<a. .., >fi ill""' ''f'PI r 'flIr ~ I • •

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ABSTR ACT. In this paper a study has been made o f ava ilable potential energy ond its trans.formation into kinetic en ergy d the dilTerent wea ther systems for the regio n o f S011lh As ia for thetypic..! monsoon month of July 1963. Energe tics o f the sta ndi ng eddies and transient eddies have beenseparately computed. Interactions amongst themsel ves and with mean zo nal flo w have been st udied

It is Inle rrcd that zo nal current is the source of avai lable pot ential energy fo r both standing lindtransie nt eddies: standing eddy is the source of kinetic energy for zo nal current and tran sient eddies.However. When the regio n of mOOS(lOn troug h is con side red. standing eddy gains kineti c energy fromtransient eddy sugge sting the Importance of mo nsoo n de pressions in strengthening the mon soon trough .Avail able pote ntial energy is co nverted into kine tic energy in the C:I'CS of both zonal cu rrent and thestanding cody. The ge neration of avai lable potential ener gy and the energy advec ted into the urea ofinterest. together exceed the losses due to dissipation of kinetic ene rgy.

1. Introduct ion

This study perw i;t; to tho e;t~ rgy aspect s of the mon­soon circ ulat ion. In the first par: of the paper (here­after called I) the d iabatic hea ting an d thc generat ion

, of a vailabl e potential energy comp uted over the mon­soo n region have been d iscussed . In tho present paperwh ich for ms par t II of tho st udy, the energy terms.the ir fluxes, the energy co nversion terms and the dissipa­t ion of kinetic energy are computed fo r the typicalmonsoon month of Ju ly. As mentioned in I, monsooncirc ulati on is considered as the mean zoml 110 11' withthe standing edd ies an d the tra nsient eddie; superimpo­sed on it. The energetics of the stan ding eddies and thetransient edd ies have been separately computed a ndst udied , to understa nd the interaction amongst them­solves a nd the ir inte ract ion; with the mean zonal flow.As only a limited region is considerecl, the va riousenergy fluxes ha ve been computed. To complete theenergy now d iagra m a rough estimate of the frict iona ldissipa tion of kinetic energy a lso has been made.

2. D ata

From the da ily aero logical data of July 1963 fromabout 90 starions (Deta ils given in I), the follow ingquant ities were calculated for the standard isobariclew is, viz .• 1000. 850, 700, 500. 300 an d 100 m b .fo reach of the stations. '

(i) Mean monthly tempe rat ure. T(ii) Mea n zonal an d meridional wind compo nen ts,

Ii and v.(iii) The va riances, r l.u;", and l;:~

(;1') The covariances, ,;;-I'~ ITT'. and v' T'

The parameters tl't , ."1, ,TV';.,;;-r nod VI T'were no t computed for 1000 a nd 100 rob levels forwant of reliable data . T he abo ve nine param eters wereplotted o n sepa rate char t; for " lithe levels a nd a nalysed.The value; a t the grid point s a t tho intervals of 2. 5'lat it ude a nd longitude' were picked up from t he

, .(405)"