Informatics Publishing Limited

Sachin D. Ghude ¹, G. S. Bhat ², Thara Prabhakaran ¹, R. K. Jenamani ³, D. M. Chate ¹, P. D. Safai ¹, A. K. Karipot ⁴, M. Konwar ¹, Prakash Pithani ¹, V. Sinha ⁵, P. S. P. Rao ¹, S. A. Dixit ¹, S. Tiwari ¹, K. Todekar ¹, S. Varpe ¹, A. K. Srivastava ¹, D. S. Bisht ¹, P. Murugavel ¹, Kaushar Ali ¹, Usha Mina ⁶, M. Dharua ¹, J. Rao ¹, B. Padmakumari ¹, A. Hazra ¹, N. Nigam ³, U. Shende ³, D. M. Lal ¹, B. P. Chandra ⁵, A. K. Mishra ⁵, A. Kumar ⁵, H. Hakkim ⁵, H. Pawar ⁵, P. Acharja ¹, Rachana Kulkarni ¹, C. Subharthi ¹, B. Balaji ¹, M. Varghese ¹, S. Bera ¹, M. Rajeevan ⁷

Affiliations
1 Indian Institute of Tropical Meteorology, Pashan, Pune 411 008, IN
2 Indian Institute of Science, Bengaluru 560 012, IN
3 India Meteorological Department, New Delhi 110 003, IN
4 Savitribai Phule Pune University, Pune 411 007, IN
5 Indian Institute of Science Education and Research Mohali, Mohali 140 306, IN
6 Indian Agricultural Research Institute, Pusa, New Delhi 110 012, IN
7 Ministry of Earth Sciences, Government of India, New Delhi 110 003, IN

Abstract

The objectives of the Winter Fog Experiment (WIFEX) over the Indo-Gangetic Plains of India are to develop better now-casting and forecasting of winter fog on various time- and spatial scales. Maximum fog occurrence over northwest India is about 48 days (visibility <1000 m) per year, and it occurs mostly during the December-February time-period. The physical and chemical characteristics of fog, meteorological factors responsible for its genesis, sustenance, intensity and dissipation are poorly understood. Improved understanding on the above aspects is required to develop reliable forecasting models and observational techniques for accurate prediction of the fog events. Extensive sets of comprehensive ground-based instrumentation were deployed at the Indira Gandhi International Airport, New Delhi. Major in situ sensors were deployed to measure surface micro-meteorological conditions, radiation balance, turbulence, thermodynamical structure of the surface layer, fog droplet and aerosol microphysics, aerosol optical properties, and aerosol and fog water chemistry to describe the complete environmental conditions under which fog develops. In addition, Weather Forecasting Model coupled with chemistry is planned for fog prediction at a spatial resolution of 2 km. The present study provides an introductory overview of the winter fog field campaign with its unique instrumentation.

Keywords

Aerosols, Atmospheric Profiles, Forecasting, Winter Fog.

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T. Misra ¹, P. Chakraborty ¹, C. Lad ¹, P. Gupta ¹, J. Rao ¹, G. Upadhyay ¹, S. Vinay Kumar ¹, B. Saravana Kumar ¹, S. Gangele ¹, S. Sinha ¹, H. Tolani ¹, V. K. Vithani ¹, B. S. Raman ¹, C. V. N. Rao ¹, D. B. Dave ¹, R. Jyoti ¹, N. M. Desai ¹

Affiliations
1 Space Applications Centre, ISRO, Ahmedabad 380 015, IN

Abstract

SCATSAT-1 is the Indian Space Research Organisation’s (ISRO’s) newest Ku-band scatterometer which was launched on 26 September 2016 from ISRO’s space-port Sriharikota on-board the PSLV C35 mission. It is an advanced follow-on of OSCAT, ISRO’s first Scatterometer in space on-board the Oceansat-2 satellite, which ceased to operate in April 2014. OSCAT had been a globally acclaimed sensor during its lifetime. The data from SCATSAT-1 exhibit superior quality, and will not only serve the operational wind and weather prediction community in the years to come, but also hold the promise of securing a place in the long-term climate data records. SCATSAT-1 is a standalone scatterometer mission atop the Indian Mini Satellite (IMS-2) bus. The scatterometer payload is a two-beam, dual-polarized, conically scanning, pencil beam, real-aperture radar which measures near-surface wind vectors over ocean exploiting Bragg scattering resonance at Ku-band. It has been developed in ISRO’s Space Applications Centre, Ahmedabad in less than two and half years to replace OSCAT. Although it inherits the instrument specifications from OSCAT, several enhancements have been made in its hardware as well as in the payload characterization from the purview of miniaturization and performance improvement over OSCAT. This article highlights the hardware improvements, the payload characterization methods devised, and the performance enhancements of SCATSAT-1 over OSCAT. The in-orbit performance of SCATSAT-1 is also discussed.

Keywords

OSCAT, SCATSAT-1, Scatterometer, Sigma-0.

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