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A novel fog/low clouds detection technique has been implemented using data from the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) along with the Global Forecasting System (GFS) and the European Centre for Medium Weather Forecast (ECMWF) model wind data. The study has been carried out during fog seasons of the years 2015-2016 and 2016-2017 over six locations over the Indo-Gangetic (IG) plains. Fog is indicated if the estimated Fog Stability Index (FSI) is found to be less than the corresponding dynamically derived threshold value. The same algorithm is effective for both day and night-time analysis and has the potential to detect fog even in the presence of higher clouds. Results are validated with visibility data obtained from various meteorological stations of the India Meteorological Department (IMD) located in the IG plains and found to be in agreement in 84.63% of cases. For qualitative comparison with FSI, the Indian National Satellites (INSAT-3D) fog products have also been used. FSI could be the most effective technique for those satellites which could have a sounder sensor along with an infrared and microwave channels like the AIRS and the IASI for an improved and continuous monitoring of fog. [ABSTRACT FROM AUTHOR]

Fog is a meteorological phenomenon in which cloud has its base near to the surface which disrupts public health and transportation due to decrease in visibility. In the present study, a collective method has been implemented for detection of fog/low clouds over the Delhi Earth Station during fog season for the years 2016 and 2017. A detailed comparison has been performed with the use of ground-based cloud-base height measurements from the Ceilometer and the Indian National Satellites (INSAT-3D/3DR)-retrieved fog product. Fog/low clouds have been effectively detected by both the Ceilometer and the INSAT-3D/3DR during single-layer cloud in the range of 0-200 m in most of the cases. Since the INSAT-3D/3DR fog product is derived under clear sky condition, fog detection during multilayer clouds is a challenging task. Results indicate that the Ceilometer can capture fog/low clouds effectively even in presence of single- and multilayer clouds. Remote-sensing technology can provide better opportunity by providing complete temporal and spatial coverage of fog. The present technique which incorporates both ground-based Ceilometer and space-based INSAT-3D/3DR measurements is observed to be more promising than other conventional methods for an improved detection and monitoring of fog/low clouds. [ABSTRACT FROM AUTHOR]