The evaluation of Kain-Fritsch scheme in tropical cyclone simulation

lkj & bl v/;;u esa 25&30 vDrwcj 1999 rd dh vof/k esa mM+hlk esa vk, egkpØokrksa ds ewY;kadu dk izfr:i.k djus ds fy, dSu fÝ’k ds diklh izkpyhdj.k ;kstuk ds lkFk ,u- lh- ,- vkj- ,e- ,e- 5 dk mi;ksx fd;k x;k gSA 25 vDrwcj 1999 ds 0000 ;w Vh lh ij 90] 30 vkSj 10 fd-eh- ds f}iFkh vk/kkfjr {kSfrt iz{ks=ksa ¼Mksesu½ okys ,u- lh- ,- vkj- ,e- ,e- 5 dks 5 fnu dh vof/k ds fy, lesfdr fd;k x;k gSA bl v/;;u ds fy, izkjfEHkd vkSj ifjlhek dh fLFkfr;ksa dks ,d va’k ds varjky ij miyC/k gq, ,u- lh- bZ- ih- ,Q- ,u- ,y- fo’ys"k.k vk¡dM+ksa ls fy;k x;k gSA ;g izfr:fir fun’kZ 954 gSDVkikLdy ij izkIr fd, x, leqnz ry ds e/; nkc vkSj 58 feuV izfr lSdaM dh vf/kdre iouksa ds lkFk mM+hlk esa vk, egkpØokr dh fodklkRed fLFkfr;ksa dks izLrqr djrk gSA bl fun’kZ ls vfuok;Z vfHky{k.kksa uker% m".k ØksM] dsanz vkSj dsanz fHkfRr izfr:i.k] gjhdsu ØksM iouksa dks izkIr fd;k x;k gSA ;g fun’kZ pØokr ds LFky Hkkx esa izos’k djus ds mijkar ml LFky ds fudV 40 ls-eh- izfrfnu dh vf/kdre o"kkZ dk iwokZuqeku yxk ldrk gS A ;g fun’kZ 24 ?kaVksa es 120 fd-eh- =qfV;ksa vkSj 120 ?kaVksa esa 0 fd-eh- dh deh ds lkFk egkpØokr ds iFk dk ,dne lgh vkdyu izLrqr djrk gSA In this study NCAR MM5 with the cumulus parameterization scheme of Kain-Fritsch is used to simulate the evaluation of Orissa Super Cyclone for the period 25-30 October 1999. The NCAR MM5 with two-way nested horizontal domains of 90, 30 and 10 km are integrated for five days starting from 0000 UTC of 25 October, 1999. The initial and boundary conditions for this study have been taken from NCEP FNL analysis data available at 1° resolution. The model simulation produces the development of the Orissa Super Cyclone with attained central sea level pressure of 954 hPa and maximum wind of 58 msec-1. The essential characteristics such as warm core, eye and eye-wall simulation, hurricane core winds were obtained by the model. The model could predict a maximum rainfall of 40 cm/day near the landfall point. The model produces a very good estimate of track with errors of 120 km at 24 hours and decreasing to 0 km at 120 hours.

Tropical cyclonic storms – Modeling studies in Indian Air Force

lkj & ns’k esa Hkkjrh; ok;qlsuk ¼vkbZ- ,- ,Q-½ dh lqjf{kr mM+kuksa ds fy, ekSle lsok,¡ miyC/k djkus dk mRrjnkf;Ro ekSle foKku foHkkx ds funs’kky; dk gSA Hkkjrh; ok;qlsuk ds csl ij fLFkr ekSle ¼esV½ dk;kZy; m".kdfVca/kh; pØokrksa ds cuus] rhoz gksus vkSj mudh xfr dk lw{e :Ik ls ekWuhVju djrs gSa rFkk ok;qlsuk dh cgqewY; lEifRr] eq[; :Ik ls gokbZ&tgktksa dh lqj{kk ds fy, psrkouh tkjh djrs gSaA pØokr ds izdksi ls izHkkfor fdlh Hkh LFkku ij cpko dk;ksaZ esa yxs gsyhdkWIVjksa@ok;q;kuksa ds fy, Hkh ;g dk;kZy; ekSle lsok,¡ miyC/k djkrs gSaA ekWMy ij fd, x, v/;;uksa ds vk/kkj ij okLrfod le; iwokZuqeku ds fy, Hkkjrh; ok;qlsuk }kjk 'kks/k dk;Z fd;k tk jgk gSA xzsy vkSj dSu&fÝ’k 2 ¼lrgh laogu lfgr½ diklh izpkyhdj.k ;kstuk dk mi;ksx djds pØokr ds ekxZ ds iwokZuqeku ds fy, Hkkjrh; ok;qlsuk ds ekSle vuqHkkx }kjk mM+hlk ds egkpØokr ds eslksLdsy fun’kZ ,e- ,e- 5 ds vk/kkj ij v/;;u fd;k x;k gSA xzsy ;kstuk ls rwQku ds okLrfod ekxZ ls yxHkx fudV ds ekxZ dk irk pyk gSA dSu&fÝ’k 2 ;kstuk ls irk pys ekxZ ls if’pe caxky vkSj mlds vkl&ikl ds {ks=ksa esa pØokr ds izfrorZu dk irk pyk gSA The Directorate of Meteorology is responsible for the provisioning of weather services for safe conduct of Indian Air Force (IAF) flying operations in the country. The Meteorological (Met) Sections at IAF bases closely monitor a Tropical Cyclone formation, intensification and movement and issue storm warning to safeguard its valuable property that primarily includes Aircrafts. It also provides the weather services for all the helicopter/Aircraft Rescue Operations that are taken up after the fury of the cyclone experienced at a place. Generation of real time forecast from model studies is in the Research Stage in IAF. A meso-scale model (MM5) studies of super cyclone of Orissa were carried out by IAF Met to generate forecast tracks of the Cyclone using Grell and Kain-Fritsch 2 (with shallow convection) cumulus parameterization scheme. The Grell scheme indicated the track slightly close to the actual track of the storm. The KF2 scheme led to the generation of the track that indicated the re-curvature of the system in to West Bengal and adjoining regions.

Effects of the Convective Triggering Process in a Cumulus Parameterization Scheme on the Diurnal Variation of Precipitation over East Asia

Effects of the convective triggering process in a cumulus parameterization scheme on the diurnal variation of precipitation over East Asia are examined using a regional climate model. Based on a cloud-resolving simulation showing the irrelevance of convective inhibition once convection is initiated and the sensitivity experiments to trigger conditions, the triggering process in the simplified Arakawa-Schubert (SAS) convection scheme is modified to use different convective initiation and termination conditions. The diurnal variation of precipitation frequency with the modified triggering process becomes in phase with the observed one, leading to a delayed afternoon peak in precipitation rate that is in better agreement with the observation. However, the bias in the phase of precipitation intensity is not resolved and the bias of excessive precipitation increases, indicating that adequate representation of not only the triggering process but also other moist convective processes that determine the strength of convection is required for further improvement in the simulation of the diurnal variation of precipitation.