Editing Waterlogging severity index (section)

== Monitoring and Measurement ==
Monitoring of waterlogging severity relies primarily on soil moisture observations within the root zone, typically extending to depths where crop roots are active. Soil moisture data are collected through a combination of ground-based sensors, remote sensing platforms, and hydrological models. Key institutions involved in soil moisture monitoring include the European Space Agency (ESA), which operates the Soil Moisture and Ocean Salinity (SMOS) mission, and the National Aeronautics and Space Administration ([https://en.wikipedia.org/wiki/NASA NASA]), which operates the Soil Moisture Active Passive (SMAP) mission. These satellite missions provide global soil moisture datasets that are essential for assessing waterlogging conditions.

Additionally, national agencies such as the United States Department of Agriculture (USDA) and the National Oceanic and Atmospheric Administration ([https://en.wikipedia.org/wiki/National_Oceanic_and_Atmospheric_Administration NOAA]) contribute soil moisture data relevant to agricultural monitoring. The USDA's National Agricultural Statistics Service (NASS) and NOAA's National Weather Service (NWS) provide complementary soil moisture information through ground observations and modeling efforts. Scientific methods for soil moisture measurement include in situ sensors (e.g., time domain reflectometry), remote sensing retrieval algorithms, and data assimilation techniques that integrate multiple data sources to improve accuracy and spatial coverage.

Within the SIGNAL system, this phenomenon is treated as a defined environmental signal whose boundaries and measurement conventions are described below.