Twinkle is a space mission designed for visible and near-IR spectroscopic observations of extrasolar planets. Twinkle's highly stable instrument will allow the photometric and spectroscopic observation of a wide range of planetary classes around different types of stars, with a focus on bright sources close to the ecliptic. The planets will be observed through transit and eclipse photometry and spectroscopy, as well as phase curves, eclipse mapping and multiple narrow-band time-series. The targets observed by Twinkle will be composed of known exoplanets mainly discovered by existing and upcoming ground surveys in our galaxy (e.g. WASP, HATNet, NGTS and radial velocity surveys) and will also feature new discoveries by space observatories (K2, GAIA, Cheops, TESS).Twinkle is a small satellite with a payload designed to perform high-quality astrophysical observations while adapting to the design of an existing Low Earth Orbit commercial satellite platform. The SSTL-300 bus, to be launched into a lowEarth sun-synchronous polar orbit by 2019, will carry a half-meter class telescope with two instruments (visible and near-IR spectrographs -between 0.4 and 4.5µm -with resolving power R~300 at the lower end of the wavelength scale) using mostly flight proven spacecraft systems designed by Surrey Satellite Technology Ltd and a combination of high TRL instrumentation and a few lower TRL elements built by a consortium of UK institutes. The Twinkle design will enable the observation of the chemical composition and weather of at least 100 exoplanets in the Milky Way, including super-Earths (rocky planets 1-10 times the mass of Earth), Neptunes, sub-Neptunes and gas giants like Jupiter. It will also allow the follow-up photometric observations of 1000+ exoplanets in the visible and infrared, as well as observations of Solar system objects, bright stars and disks.

Moisture profiles have been estimated over the region bounded by the latitudes 40~ and 40~ and longitudes 30~ to 130~ using INSAT digital infra red cloud imagery data. The representativeness of these profiles in representing moisture field associated with the development and movement of synoptic scale systems during the period September 15th, 1996 to March 31st, 1997 has been examined. It has been shown that the changes in the moisture field associated with the withdrawal of the southwest and northeast monsoons from the Indian sub-continent, development and movement of synoptic scale sytems (depressions, tropical cyclones and waves in easterlies) and equatorial troughs in the Indian Ocean could be clearly seen in humidity profiles. The initial development of tropical systems is first seen in the humidity field in the upper troposphere. These profiles could be used in monitoring the initial development and subsequent movement of tropical systems. Further the data on moisture distribution from the data gap regions of the Indian Ocean could be used as an additional source of moisture in numerical analysis and prognosis.

Lkkj & balSV ls izkIr lh- ,e- oh- dh xq.krk vk’oklu ¼D;w- ,-½ tk¡p izkjaHk esa ,u- lh- bZ- ih- okf’kaxVu vFkok bZ- lh- ,e- MCY;w- ,Q- ls izkIr 12 ?kaVs ds fuEu foHksnu iwokZuqeku ds vk¡dM+ksa dk mi;ksx djds dh tkrh gSA fgan egklkxj ds vi;kZIr vk¡dM+ksa okys {ks= ls balSV vFkok vU; mixzgksa ls izkIr lh- ,e- oh- dk mi;ksx bu iwokZuqekuksa esa izkjaHk esa ugha fd;k tkrk FkkA vU; dsUnzksa dks balSV ls izkIr lh- ,e- oh- dh xq.krk fo’oluh; Lrj dh ugha yxhA tqykbZ 98 ls igys] balSV ds vykok fdlh vU; mixzg ls fgan egklkxj ds vi;kZIr vk¡dM+ksa okys {ks= ds vk¡dM+s izkIr ugha gq,A tqykbZ 98 esa] ehfVvkslSV&5 dks fgan egklkxj ds Åij 63 fMxzh iwoZ dh vksj f[kldk;k x;kA balSV ekSle foKku vk¡dM+k lalk/ku ra= ¼vkbZ- ,e- Mh- ih- ,l-½ esa balSV ls lh- ,e- oh- izkIr djus dh izpkyukRed ;kstuk esa dqN egRoi.kZ lq/kkj fd, x, ftlls mi;ksxdrkZvksa dks csgrj xq.krk  ds mixzg ls izkIr iou ds vk¡dM+s miyC/k djok, tk ldsaA la’kksf/kr ,yxksfjFe esa xq.krk vk’oklu tk¡p esa ,y- ,- ,e- iwokZuqeku dk mi;ksx fd;k x;k gSA LiSDVªe dh 'khr ifjf/k ij es?kksa  ds dqN izfr’kr ds vkSlr rkieku ds vk/kkj ij nkc vkSj m¡pkbZ;k¡ fu/kkZfjr dh tkrh gSaA balSV vkSj ehfV;kslsV&5 ls izkIr lh- ,e- oh dk foLrkj ls rqyukRed v/;;u fd;k x;k gSA  balSV vkSj ehfV;kslsV-5 ls izkIr ifj"Ñr lh- ,e- oh- ds chp xq.krk ds vk/kkj ij vPNh vuq:irk dk irk pyk gSA vfHkufr vkSj vkj- ,e- ,l esa Hkh lq/kkj gq, gSaA lh- ,e- oh- esa igys izsf{kr {ks=h; iouksa esa Hkh lq/kkj gqvk gSA ehfV;kslsV&5 dh rqyuk esa balSV ls izkIr lh- ,e- oh- dh de la[;k dk dkj.k balSV jsfM;ksehVj dk fuEu LFkkfud foHksnu gSA fp=ksa ds f=d ls rS;kj lh- ,e- oh- ds nks lSVksa dks lfEefyr fd;k x;k ftlesa nks lSVksa esa LFkkfir lh- ,e- oh- dks 'kkfey ugha djus dk  /;ku j[kk x;k gSA balSV  ls izkIr ifj"Ñr lh- ,e- oh- ls ekWMy }kjk fd, tkus okys iwokZuqeku ij ldkjkRed izHkko iMk gSA Earlier Quality Assurance (QA) tests of INSAT derived CMVs were done using low resolution 12 hour forecast from NCEP Washington or ECMWF. These forecasts earlier did not use satellite derived CMVs from INSAT or other satellites from data sparse Indian Ocean. Other centers did not find INSAT CMVs of reliable quality. Before July 1998, no other satellite except INSAT covered the data sparse Indian Ocean. In July 1998, METEOSAT-5 was shifted over Indian Ocean at 63 degree East. Certain vital changes have been incorporated in the operational scheme of INSAT CMVs derivation at INSAT Meteorological Data Processing System (IMDPS) for providing satellite derived winds of improved quality to the users. The modified algorithm uses LAM forecast in QA tests. Pressures and heights are assigned on the basis of mean temperature of certain percentage of cloud population at the cold end of the spectrum. Detailed comparison of CMVs from INSAT and METEOSAT-5 has been done. The improved CMVs from INSAT and METEOSAT-5 show quite good agreement qualitatively.  The bias and RMS also show improvements. Zonal winds observed earlier in CMVs have shown improvement. The lesser number of INSAT CMVs is due to lower spatial resolution of INSAT radiometer compared to METEOSAT-5. The two sets of CMVs generated from triplet of images are being combined, taking care of excluding the collocated CMVs in the two sets. The improved INSAT derived CMVs have shown positive impact on the Model forecast.

No abstract

The impact of humidity profiles estimated from INSAT digital IR cloud imagery data on initial moisture analysis in the IMD's operational limited area forecast system has been investigated. Method for assimilation of humidity profiles data as pseudo observations in the analysis scheme has been developed and implemented in the regional analysis scheme. Verification of humidity analysis with this data has shown substantial improvements in the moisture analysis over the data sparse region of tropics. Impact of the improved humidity analysis on model predicted rainfall is examined. The experiments show improved rainfall prediction.