Sentinel-Hub NDMI description:

The NDMI is a normalized difference moisture index, that uses NIR and SWIR bands to display moisture. The SWIR band reflects changes in both the vegetation water content and the spongy mesophyll structure in vegetation canopies, while the NIR reflectance is affected by leaf internal structure and leaf dry matter content but not by water content. The combination of the NIR with the SWIR removes variations induced by leaf internal structure and leaf dry matter content, improving the accuracy in retrieving the vegetation water content. The amount of water available in the internal leaf structure largely controls the spectral reflectance in the SWIR interval of the electromagnetic spectrum. SWIR reflectance is therefore negatively related to leaf water content. In short, NDMI is used to monitor changes in the water content of leaves and was proposed by Gao. NDWI is computed using the near-infrared (NIR) and the short wave infrared (SWIR) reflectances:

NDMI = (NIR – SWIR) / (NIR + SWIR)

Sentinel-2 NDMI = (B08 - B11) / (B08 + B11)

These data have been created by the Joint Nature Conservation Committee (JNCC) as part of a Defra Natural Capital and Ecosystem Assessment (NCEA) project to produce a regional, and ultimately national, system for detecting a change in habitat conditions at a land parcel level. The first stage of the project is focused on Yorkshire, UK, and therefore the dataset includes granules and scenes covering Yorkshire and surrounding areas only. The dataset contains Normalised Difference Moisture Index data derived from Defra and JNCC Sentinel-2 Analysis Ready Data.

NDMI files are generated for the following Sentinel-2 granules:

• T30UWE

• T30UXF

• T30UWF

• T30UXE

• T31UCV

• T30UYE

• T31UCA

As the project continues, JNCC will expand the geographical coverage of this dataset and will provide continuous updates as ARD becomes available.