INSAT-3DR Augments INSAT-3D for Improved Weather Monitoring and Prediction
Three-dimensional observations of atmosphere along with the land and ocean are required for various applications. One of the most important applications is weather prediction that is very crucial in planning of day-to-day events affecting human life in many ways. Knowledge of weather parameters is also important for controlling the agricultural production. For example, adequate amount of rainfall at the time of sowing and favourable temperature and moisture conditions during different phases of crop growth is very important for healthy crop production. With increased focus on the monitoring and forecasting of rapidly evolving weather processes the need for improved temporal and spatial observations has become more critical.
Historically, such weather information was obtained through a network of ground observatories established by meteorological establishments, such as India Meteorology Department (IMD). However, this information was limited to a few selected cities. A satellite provides continuous observations over an entire viewing region including ocean, desert, mountains, etc,. that were difficult from the ground network.
India realised the importance of satellites for land-atmosphere-ocean observations and it has become a major thrust area for the Indian Space Programme (ISP). In this direction the INSAT series of multi-purpose geostationary satellites, conceived in the early eighties, became pivotal to meet the operational needs of weather services in the country.
After realising its potential for meteorological applications, ISRO initiated work on the dedicated satellites for meteorological applications during last decade. ISRO launched its first exclusive meteorological satellite, Kalpana-1, on September 12, 2002. Kalpana-1 has a Very High Resolution Radiometer (VHRR) with three channels providing weather parameters like Atmospheric Motion Vectors (AMV), Rainfall estimates, Upper Tropospheric Humidity, Outgoing Longwave Radiation, Sea Surface Temperature (SST) and various other agromet parameters. The half-hourly image sequences are used for the monitoring of important weather events like heavy rainfall, onset of monsoon, tropical cyclone, and numerical weather prediction.
Kalpana-1 was followed by a quantum jump in the observational capability of ISP with the launch of INSAT-3D in July 2013. INSAT-3D satellite with a 19-channel Sounder and a 6-channel advanced Imager is helping in the identification of the sporadic natural hazards like flash floods, cyclones, wildfire, fog, upper air turbulence, thunderstorm, etc.
INSAT-3D was followed by the INSAT-3DR that was launched by GSLV-F05 rocket into the geostationary transfer orbit on September 08, 2016. INSAT-3DR is identical to INSAT-3D in configuration. The atmospheric vertical profiles of temperature and humidity from INSAT-3D/3DR Sounders have added a new dimension in the observational capability for monitoring and predicting the rapidly developing weather systems. Sounder instruments provide 3-dimensional thermodynamic structure of the atmosphere over Indian landmass allowing the forecasters to identify the areas of possible severe weather conditions such as thunderstorm well in advance.
The combination of INSAT-3D and INSAT-3DR provide the multi-spectral images of the earth and the atmosphere at every 15-minute interval from Imager and 30-minute interval from the Sounder that ensures more accurate and timely detection of weather parameters around the Indian subcontinent.
INSAT-3D/3DR Imagers have split-window thermal infrared channels for accurate estimation of SST. Addition of a new 3.9 micron channel helps in improved SST estimation besides helping in locating the forest-fire events and also in identifying the fog covered areas. Shortwave infrared band at 1.4 micron helps in identification of the snow cover, and the phase of water in the clouds. The visible channel along with other Imager channels provides the cloud information. The improved spatial and temporal resolutions in INSAT-3D/3DR Imagers has paved way for more accurate estimates of AMV winds that results in improved weather prediction. The Upper tropospheric humidity and Outgoing Longwave Radiation are helping in monitoring the deep convection. These parameters are also important indicators of climate change. Rainfall estimates generated at 15-minute interval are important for agriculture. INSAT-3D/3DR Imagery with enhanced spatial and temporal resolutions also provide an excellent insight into the patterns of cyclonic activity over India, helping in the improved cyclone track prediction and intensity estimation.
During clear-sky conditions, the INSAT-3D/3DR imageries help in capturing different land cover types such as cropland, forest, desert, grassland, wetlands, inland water bodies, snow-glacier, etc,. in optical and thermal bands. Atmospheric haze due to dust aerosols and transport of dust can also be identified from Imager optical band.
All these geo-physical data products of INSAT-3D/3DR are disseminated through Metrological and Oceanographic Satellite Data Archival Centre (MOSDAC) for in-house R&D work and other users.
Images from INSAT-3DR Imager channel (left, centre) and MWIR-1 Sounder channel (right)
Link to Cloud Cover Over India