Recent advances in Radar Meteorology in India

Radar Meteorology in India has a good heritage starting with the installation of conventional weather radars along the coast line of peninsular India by the India Meteorological Department (IMD) five decades ago. Up gradation of the Cyclone warning network with modern Doppler Weather Radar (DWR) systems was done in a phased manner with a complement of both imported and indigenously designed systems. Indian Space Research Organization ( ISRO), Department of Space , designed and developed a S Band Doppler Weather Radar named Megha -2700 based on the requirements spelt out by IMD. The paper describes the salient features, including Polarimetric option, of this radar in some detail and provides some typical case studies of Bay of Bengal Cyclones observed and characterized by this radar , located at Sri Hari kota island , the Space Port of India. A few cases of thunderstorm activity studied essentially to provide Launch Commit Criteria for Satellite Launch Vehicle Missions. Utilizing opportunities of common visibility, inter comparison between this ground based DWR and TRMM – PR were made to establish bias in precipitation intensity. A well planned inter comparison with a dedicated network of ground based fast response rain gauges was made and the results will be presented. Based on Technology Transfer from ISRO to Bharat Electronics Ltd ( BEL) resulted in production of this indigenous DWR , along with some improvements as necessitated based on IMD's needs, especially in terms of derived data products, the details of which are also provided. The paper also gives some details of the imported DWR systems of IMD forming the DWR network at present.

Based on the scientific & research interests in Meso scale meteorology, Quantitative Precipitation Estimation (QPE) and cloud physics , ISRO has embarked on indigenous design and development of Doppler , Polarimetric Weather Radar systems in C,X, & Ka Bands. These Radars are in an advanced state of development and are expected to be commissioned in about a year. Details of these systems will also be presented.

Establishment of a powerful Mesosphere Stratosphere & Troposphere (MST) Radar as a national facility for Atmospheric research by ISRO , has resulted in considerable amount of advances in our understanding of Tropical atmospheric dynamics, including the variability of tropical tropo pause and the exchange mechanisms between troposphere and troposphere a well as the propagation of gravity waves. Some of the interesting findings will be described in this paper.

Based on the success of the MST radar , Department of Science & Technology (DST) of the Government of India decided to establish a network of smaller Stratosphere Troposphere (ST) radars, operating in the 200MHz band to take advantage of the lower sky noise temperature as compared to the 50MHz band in which the bigger MST radar operates. The ST radar is configured as an Active Aperture Phased array with individual TR modules powering each element of the 588 element array. The first of the ST radars is being installed at Aryabhatta Research Institute of Observational Sciences (ARIES) at Nainital in the Himalayan mountains, with the objective of monitoring trans Himalayan flow of pollutants, along with other co-locatable instruments like Lidars. The paper describes this new ST radar and also gives an insight into the ST Radar network. Details of all the radar systems and the important observations made with them are also provided. The paper concludes by providing a peak at the future in the area of Radar meteorology in India.