February 14, 2026

NASA-ISRO Synthetic Aperture Radar (NISAR) is systematically imaging the Indian landmass in S- and L-bands to deliver high resolution and wide swath data, with a repetivity of 12 days. This data has been effectively utilized to demonstrate the generation of soil-moisture products at a high resolution of 100m. Being a key indicator of crop health, irrigation need and drought risk, soil-moisture plays a vital role in India’s agriculture and water management.

The soil-moisture products, demonstrated using both S- and L-band data, provide consistent estimates across India’s diverse agro-climatic regions - from irrigated plains and rainfed farmlands to semi-arid and high-rainfall zones. The physics-based soil moisture retrieval algorithm, developed at Space Applications Centre (SAC-ISRO), ensures scientific robustness, reliability, and operational accuracy.

With the ability to deliver two observations every 12 days, NISAR enables near-real-time tracking of soil moisture dynamics. This frequent monitoring supports irrigation planning, drought preparedness, agrometeorological advisories, and regional water resource management at scales relevant to districts and farming communities.

To support national operations, the 100 m Level-4 operational soil moisture products with two observations every 12 days will be systematically generated at National Remote Sensing Centre (IMGEOS/NRSC) and disseminated through the Bhoonidhi Portal, ensuring seamless access for farmers, planners, researchers, government agencies and Non-Government Entities (NGEs) across the country.

The results shown here illustrate multiple full-swath 100 m L- & S-band soil moisture products over various agro-climatic regions of India to illustrate consistent large-scale wetness patterns suitable for national agricultural and hydrological monitoring:

• Western India – semi-arid moisture stress conditions (Figure-1)
• Northern India including Indo-Gangetic Plains – irrigation-driven variability (Figures-2 & 3)
• Central India – rainfed agricultural zones (Figure-4)

These results collectively confirm the operational readiness, scalability, and reliability of NISAR’s soil moisture products for nationwide applications.

The results also highlight the complementary strengths of the two frequencies, L- and S-bands, of NISAR for reliable operational soil moisture retrieval. While L-band enables deeper penetration and improved sensitivity under vegetation and crop cover, S-band provides enhanced surface sensitivity and finer spatial detail. These advantages pave the way for more robust combined dual-frequency based products across varied agricultural landscapes.

These preliminary products are undergoing systematic evaluation over core soil moisture calibration/validation sites across India, representing diverse soil textures, rainfall regimes, and cropping systems. Ground measurements using in-situ soil moisture sensors and stations are employed to refine accuracy and ensure confidence for operational deployment.

Further developments for finer resolution field-scale soil moisture products are in progress to capture sub-field moisture dynamics.

NISAR: A National Asset for Data-Driven Agriculture

The NISAR 100 m Level-4 operational soil moisture products represent significant advancement in India’s Earth observation capability. By delivering frequent, high-resolution, and physically consistent soil moisture information from space, NISAR empowers farmers, planners, Non-Government Entities (NGE) and policymakers with actionable intelligence for sustainable agriculture, efficient irrigation, and national food & water security.