The NISAR mission will help map crops and track their growth throughout the growing season. Satellites use synthetic aperture radar to observe small areas of farmland and monitor trends in vast areas, collecting data to provide a basis for agricultural decision-making.
The NISAR satellite will revolutionize global agriculture by providing high-resolution, frequently updated crop and soil moisture radar data. This breakthrough will allow farmers and policymakers to optimize cropping plans, irrigation and resource allocation with unprecedented precision. Unlike traditional satellites, NISAR's dual-frequency radar can penetrate clouds and crop canopies to provide insights into biomass, soil moisture and plant health.
The NISAR (NASA-ISRO Synthetic Aperture Radar) satellite launched this year will provide a powerful data stream to support farmers in the United States and around the world. Developed jointly by NASA and the Indian Space Research Organization (ISRO), the mission will track the growth of crops from sowing to harvest, providing important insights to help farmers optimize seeding plans, improve irrigation and make the most of their time.
Equipped with synthetic aperture radar, NISAR will analyze the physical properties of crops and measure plant and soil moisture. While it has the accuracy to monitor small plots of farmland, its biggest advantage is its ability to cover agricultural areas frequently and on a large scale.
The satellite will capture images of nearly all of Earth's landmasses twice every 12 days, with a resolution capable of detecting patches as small as 30 feet (10 meters) across. This level of detail will allow users to track week-to-week changes on individual farms, or zoom in to see trends across an entire region. This comprehensive perspective is valuable to policymakers and agricultural managers making decisions regarding crop production and resource allocation.
For example, using NISAR data, policymakers can estimate when rice seedlings will be planted in an area and track their height and flowering throughout the season, while also monitoring the humidity of the seedlings and paddy fields over time. Unhealthy crops or drier rice fields may signal the need for changes in management strategies.
"It's all about resource planning and optimization, and when it comes to crops, timing is very important: When is the best time to plant seeds? When is the best time to irrigate?" said Narendra Das, a member of the NISAR science team and an agricultural engineering researcher at Michigan State University in East Lansing. "That's the crux of the whole game."
NISAR will be launched this year from the Indian Space Research Organization's Satish Dhawan Space Center on India's southeastern coast. Once put into operation, it will provide approximately 80TB of data products to researchers and users in many fields, including agriculture, every day.
Satellites have been used for large-scale crop monitoring for decades. Because microwaves can pass through clouds, radar is better at observing crops during the rainy season than other technologies such as thermal and optical imaging. The NISAR satellite will be the first radar satellite to use two frequencies (L-band and S-band), which will allow it to observe a wider range of surface features than a single instrument using one frequency.
The microwaves emitted by the mission radar will be able to penetrate the canopy of crops such as corn, rice and wheat and then bounce back to the sensor from plant stems, soil or water below. This data allows users to estimate the mass of plant matter (biomass) on the ground in an area. By interpreting data over time and combining it with optical images, users will be able to differentiate crop types based on growth patterns.
In addition, NISAR's radar will measure changes in the polarization (or vertical and horizontal directions) of the signal after it bounces off the Earth's surface and back to the satellite. This will enable a technique called polarimetry, which when applied to the data will help identify crops and estimate crop yields with greater accuracy.
"Another superpower of NISAR is that when its measurements are combined with traditional satellite observations, especially vegetation health indices, they will greatly enhance crop information," added Brad Doorn, who oversees NASA's water resources and agriculture research programs.
The high-resolution data provided by the NISAR satellite can be used for agricultural productivity forecasts, showing which crops are growing and how well.
"The Indian government - or any government in the world - would like to know crop area and yield estimates in a very precise manner. NISAR's highly repetitive time series data will be very, very useful," said Bimal Kumar Bhattacharya, head of agricultural applications at ISRO's Center for Space Applications in Ahmedabad.
NISAR satellites can also help farmers measure water content in soil and vegetation. Generally speaking, wetter soils tend to return more signals and appear brighter in radar images than drier soils. A similar relationship exists for plant moisture.
These capabilities mean that NISAR can estimate the moisture content of crops during the growing season, helping determine whether crops are suffering from water shortages, and can also estimate soil moisture using signals scattered back from the ground.
Soil moisture data has the potential to inform agriculture and water managers about how farmland responds to heatwaves or droughts, and how quickly farmland absorbs water and dries out after rain - information that could support irrigation planning.
"Resource managers thinking about food security and where resources are going will be able to use this type of data to get a holistic view of the entire region," said Rowena Lohman, a geoscience researcher at Cornell University in Ithaca, New York, and the soil moisture lead on the NISAR science team.
The NASA-ISRO Synthetic Aperture Radar (NISAR) satellite is a groundbreaking Earth observation mission and marks the first collaboration between NASA and ISRO on flight hardware. Designed to monitor changes in Earth's land and ice surfaces with unparalleled accuracy, NISAR features L-band and S-band dual-frequency radar to capture detailed images of environmental changes, natural disasters and climate impacts.
NASA's Jet Propulsion Laboratory (JPL) leads the U.S. portion of the program, providing the L-band synthetic aperture radar, radar reflector antenna, deployable boom, high-speed communications subsystem, GPS receiver, solid-state recorder and payload data subsystem. NASA's Goddard Space Flight Center manages the near-space network, which will receive L-band data.
The ISRO Space Applications Center developed the S-band synthetic aperture radar, and the URRao Satellite Center provided the spacecraft bus. The mission will be launched from the launch vehicle of Vikram Sarabhai Space Center and launch services will be carried out from Satish Dhawan Space Centre. After entering orbit, it will be managed and operated by the Indian Space Research Organization Telemetry, Tracking and Command Network (ISTRAC), and the National Remote Sensing Center (NRSC) will be responsible for the reception and distribution of S-band data.
By combining the two agencies' advanced radar technologies, NISAR will provide valuable insights into changes in the Earth's surface to support disaster response, environmental monitoring and climate research.
Compiled from /ScitechDaily