A Quality Assured in-situ Real-Time Soil Moisture Monitoring Network for the Indus Basin

Soil moisture is an essential climate variable with an important role in the hydrological cycle, and is critical for agricultural water management, floods & droughts monitoring, forest-fire control, locust attack prediction and many other applications. While there exist several in-situ soil moisture networks across the globe, there is an absence of a large-scale network for the Indus Basin. This paper summarizes our five years of work in the Indus basin to establish a soil moisture monitoring network, WITSMS-Network with more than 200 installations, primarily to empower farmers for real-time irrigation scheduling. The sensors were calibrated using the gravimetric method with a R
²
value of 0.9388 and RMSE of 0.025 m
³
m
⁻³
for WIT’s indigenously developed WZ-1 soil moisture probe. Both WZ-1 and commercially available soil moisture probes were integrated into an IoT hardware-software backbone for real-time data transmission, storage and sharing over the Internet. We also offer an approach to validate the soil moisture network, based on TCA metrics, against coarse resolution satellite and model-based soil moisture products including SMAP-L2, C3S SM combined, ESA CCI SM combined, and ECMWF ERA5-Land model. Our network achieved an ubRMSD 0.0460 m
³
m
⁻³
over 2 years of soil data records. These reproducible validation results have been generated using a community-wide accepted QA4SM validation framework. The soil moisture data is being published at ISMN under WIT-Network
¹
.