D-ESSM - Home

Product overview¶

D-ESSM uses Spire’s downscaling methodology to enhance the spatial resolution of D-MSSM from 6 km to 500 m. Long-term Sentinel-1 SAR backscatter data establishes a robust connection between regional and local-scale soil moisture conditions. Where downscaling cannot be applied (densely vegetated areas, cities, water bodies), the pixel is infilled with D-MSSM gridded to 500 m.

Figure 1:D-ESSM enhanced surface soil moisture over Mexico, 30 August 2025. Values in m³/m³.

Property	Value
Spatial resolution	500 m (0.0045° grid spacing)
Data level	L5
Temporal coverage	May 2015–present
Coverage	Global
Unit	m³/m³

Variants:

d-essm — Standard product with ~4-day latency
d-essm-nrt — Near-real-time product with ~1-day latency

NetCDF4 format¶

Global attributes¶

Attribute	Description
`description`	Daily Enhanced Surface Soil Moisture
`creator`	SPIRE GLOBAL
`processing_center`	Spire EILAND
`file_created_time_utc`	UTC creation timestamp
`data_level`	L5
`source`	D-MSSM vMA.mi and Sentinel-1 downscaling parameters vMA.mi
`input_data_version`	Input data release version (e.g. v02.01.98)
`release_tag`	Data release version (e.g. v04.00.98)
`code_version`	Production code version (may not be present in all files)
`git_hash`	Production code commit hash (may not be present in all files)
`grid_mapping`	spatial_ref
`feed`	Data tier: `"standard"` or `"nrt"`

Variables¶

Variable	Description	Dims	Type	Fill value	Scale factor	Unit
`d_essm`	Daily Enhanced Surface Soil Moisture downscaled from D-MSSM	(y, x)	uint8	255	0.005	m³/m³
`eflag`	Enhanced flag — indicates where downscaling was applied	(y, x)	uint8	255	—	—
`qflag`	Quality flag — 8-bit flags recording surface conditions	(y, x)	uint8	255	—	—
`aflag`	Advisory flag — 0 = recommended, 1 = not recommended	(y, x)	uint8	255	—	—
`y`	Latitude coordinate	(y)	float64	NaN	—	degrees_north
`x`	Longitude coordinate	(x)	float64	NaN	—	degrees_east
`spatial_ref`	Coordinate reference system (WGS 84, EPSG:4326)	()	int64	—	—	—

Enhanced flag (eflag)¶

The eflag indicates whether the pixel value comes from the downscaled (enhanced) product or from the fallback D-MSSM gridded to 500 m:

0 — Enhanced (downscaling was applied, i.e. D-ESSM)
1 — Not enhanced (D-MSSM infill at 500 m)

Quality flag (qflag)¶

The D-ESSM quality flag uses 8 bits and has different condition definitions compared to D-MSSM, reflecting the higher-resolution ancillary datasets used.

Bit	Condition	Interpretation
0	Terrain ruggedness	0: not present; 1: complex topography present
1	Urban area	0: no urban area; 1: urban area detected
2	Permanent water body	0: no permanent water body; 1: permanent water body detected
3	Periodic water body	0: no periodic water body; 1: periodic water body detected
4	Dense vegetation	0: no dense vegetation; 1: dense vegetation detected
5	Patchy vegetation	0: no patchy vegetation; 1: patchy vegetation detected
6	RMSE of downscaling	0: no model mismatch; 1: spatiotemporal model mismatch between fine- and coarse-scale soil moisture
7	Freeze/thaw	0: no frozen ground; 1: frozen ground detected

Sources of conditions at 500 m resolution:

Terrain ruggedness: Terrain Ruggedness Index (TRI) derived from the 90 m Copernicus DEM (2021-1). Pixels with a median TRI exceeding a high threshold are flagged.
Urban areas / Dense vegetation: Derived from ESA WorldCover v200 (2021) at 10 m, downsampled to 500 m.
Permanent / Periodic water bodies: Derived from the JRC Global Surface Water product (VER5-0) seasonality layer.
Patchy vegetation: Derived from ESA WorldCover v200.
RMSE of downscaling: Indicates model mismatch between fine- and coarse-scale soil moisture.
Freeze/thaw: Carried over from D-MSSM input, upsampled from 6 km to 500 m.

GeoTIFF format¶

D-ESSM GeoTIFF files contain encoded soil moisture values with a no-data value of 255. Each delivery includes a corresponding advisory flag GeoTIFF layer.

Tag	Description
`creator`	SPIRE GLOBAL
`code_version`	Production code version
`data_level`	L5
`description`	Daily Enhanced Surface Soil Moisture
`file_created_time_utc`	UTC creation timestamp
`git_hash`	Production code commit hash
`input_data_version`	Input data release version
`processing_center`	Spire EILAND
`release_tag`	Data release version
`short_name`	D-ESSM (data) or AFLAG (flag)
`source`	D-MSSM vMA.mi and Sentinel-1 downscaling parameters vMA.mi
`units`	m³/m³
`CRS`	Coordinate Reference System

CSV and GeoJSON format¶

Variable	Description	Type	Fill value	Unit
`ref_local_time`	Reference local time for each observation	datetime64[ns]	—	—
`d_essm`	Daily Enhanced Surface Soil Moisture	float32	NaN	m³/m³
`eflag`	Enhanced flag	float32	NaN	—
`qflag`	Quality flag	float32	NaN	—
`aflag`	Advisory flag	float32	NaN	—
`lat`	Latitude	float64	NaN	degrees
`lon`	Longitude	float64	NaN	degrees
`geometry`	Point geometry (WKT format)	string	—	—

JSON (point API) response¶

{
  "data": [
    {
      "location": {
        "coordinates": {
          "lat": 48.80,
          "lon": 2.30
        }
      },
      "times": {
        "valid_time": "2026-02-10 12:00:00"
      },
      "values": {
        "d_essm": 0.245,
        "eflag": 0.0,
        "qflag": 0.0,
        "lat": 48.80,
        "lon": 2.30,
        "aflag": 0,
        "feed": "standard"
      }
    }
  ],
  "meta": {
    "message": null
  }
}