Numerical prediction of the Orissa super cyclone (1999) : Sensitivity to the parameterisation of convection, boundary layer and explicit moisture processes

& ih- ,l- ;w- @ ,u- lh- ,- vkj- ,e- ,e- 5 dk mi;ksx djds mM+hlk esa 1999 esa vk, egkpØokr dh xfrfof/k;ksa vkSj mldh rhozrk ds la[;kRed iwokZuqeku dk bl 'kks/k&i= esa v/;;u fd;k x;k gSA laogu] xzgh; ifjlhek Lrj vkSj fuf’pr ueh Ldheksa dh izkpyhdj.k ;kstukvksa dh Hkwfedk dk v/;;u djus ds fy, laosnu’khyrk iz;ksx fd, x, gSaA caxky dh [kkM+h esa 90] 30 vkSj 10 fd-eh- {kSfrt varjkyksa ds rhu ikjLifjd iz{ks=ksa ¼Mksesu½ dk irk yxkus ds fy, bl ekWMy dh ifjdYiuk dh xbZ gSA ,d va’k ds varjky ij miyC/k gq, ,u- lh- bZ- ih- ,Q- ,u- ,y- vk¡dM+ksa dk mi;ksx djds izkjafHkd {ks=ksa vkSj fHkUu le; ds ifjlhek ifjorhZ rFkk 12 ?kaVs ds varjky ij leqnz lrg rkieku miyC/k djk, x, gSaA laogu] xzgh; ifjlhek Lrj vkSj fuf’pr ueh izfØ;kvksa ds laca/k esa pØokr ds ekxZ dk iwokZuqeku vkSj mldh rhozrk dh laosnu’khyrk dk v/;;u djus ds fy, rhu iz;ksx fd, x, gSaA blls izkIr gq, ifj.kkeksa ls pØokr ds ekxZ ds iwokZuqeku esa laoguh; izfØ;kvksa dh egRoiw.kZ Hkwfedk dk irk pyk gS rFkk dSu&fÝ’k 2 Ldhe ls pØokr ds ekxZ dk lcls lVhd <ax ls irk yxk;k tk ldk gSA blds vykok ;g irk pyrk gS fd xzgh; ifjlhek Lrj izfØ;k,¡ esyj&;eknk Ldhe ds lg;ksx ls lcls izpaMre pØokr dh rhozrk dks Kkr dj ldrh gSaA fuf’pr ueh izfØ;k,¡ pØokr dh xfr dks fu;af=r djrh gSa tks Hkhrjh iz{ks= ¼Mksesu½ ds 10 fd-eh- ds lw{e foHksnu ds QyLo:Ik laHko gks ldrk gSA dSu&fÝz’k 2 vkSj esyj&;eknk dh la;qDr pj.kc) ;kstuk ls pØokr ds ekxZ vkSj mldh rhozrk ds laca/kksa dks csgrj <ax ls izfr:fir fd;k x;k gSA fdlh ,dek= iz;ksx dh rqyuk esa lHkh feystqys iz;ksxksa ls pØokr ds ekxZ vkSj mldh rhozrk dk csgrj vkdyu fd;k tk ldk gSA izfr:fir pØokr esa ,diw.kZ fodflr pØokr ds] m".k ØksM] dsanz vkSj dsanz&fHkfRr tSls lHkh y{k.k ik, x, gSaA ekWMy ls izfr:fir o"kkZ forj.k vkSj rhozrk izs{k.kksa ds vuq:Ik ikbZ xbZ gSA Numerical prediction of the movement and intensification of the Orissa Super Cyclone (1999) is studied using PSU/NCAR MM5. Sensitivity experiments were made to study the role of the parameterisation schemes of convection, planetary boundary layer and explicit moisture schemes. The model is designed to have three interactive domains with 90, 30 and 10 km horizontal resolutions covering the Bay of Bengal region. The initial fields and time varying boundary variables and sea surface temperatures at 12 hour interval are provided from NCEP FNL data available at 1° resolution. Three groups of experiments were performed to study the sensitivity of the cyclone track prediction and intensification to the schemes of convection, planetary boundary layer and explicit moisture processes. The results indicate that convective processes play an important role in the cyclone track prediction and the scheme of Kain-Fritsch 2 produces the best track and the planetary boundary layer processes control the intensification with the scheme of Mellor-Yamada producing the strongest cyclone. The explicit moisture processes modulate the movement of the cyclone, which may be due to the fine resolution of the 10 km for the innermost domain. The mixed-phase scheme in combination with Kain-Fritsch 2 and Mellor-Yamada produce the best simulation in terms of the track as well as intensification. The ensemble mean of all the conducted experiments estimate the track positions and intensification better than any individual experiment. The simulated cyclone shows all the characteristics of a mature cyclone, with warm core, formation of the eye and eye wall. The model simulated rainfall distribution and intensity have good agreement with the observations.