Sentinel-1 SAR GRD: C-band Synthetic Aperture Radar Ground Range Detected, log scaling

Dataset Availability

2014-10-03T00:00:00Z–2024-11-21T17:19:56Z

Dataset Provider

European Union/ESA/Copernicus

Earth Engine Snippet

ee.ImageCollection("COPERNICUS/S1_GRD")

Tags

copernicus esa eu radar sar sentinel

backscatter

polarization

Description

The Sentinel-1 mission provides data from a dual-polarization C-band Synthetic Aperture Radar (SAR) instrument at 5.405GHz (C band). This collection includes the S1 Ground Range Detected (GRD) scenes, processed using the Sentinel-1 Toolbox to generate a calibrated, ortho-corrected product. The collection is updated daily. New assets are ingested within two days after they become available.

This collection contains all of the GRD scenes. Each scene has one of 3 resolutions (10, 25 or 40 meters), 4 band combinations (corresponding to scene polarization) and 3 instrument modes. Use of the collection in a mosaic context will likely require filtering down to a homogeneous set of bands and parameters. See this article for details of collection use and preprocessing. Each scene contains either 1 or 2 out of 4 possible polarization bands, depending on the instrument's polarization settings. The possible combinations are single band VV or HH, and dual band VV+VH and HH+HV:

1. VV: single co-polarization, vertical transmit/vertical receive
2. HH: single co-polarization, horizontal transmit/horizontal receive
3. VV + VH: dual-band cross-polarization, vertical transmit/horizontal receive
4. HH + HV: dual-band cross-polarization, horizontal transmit/vertical receive

Each scene also includes an additional 'angle' band that contains the approximate incidence angle from ellipsoid in degrees at every point. This band is generated by interpolating the 'incidenceAngle' property of the 'geolocationGridPoint' gridded field provided with each asset.

Each scene was pre-processed with Sentinel-1 Toolbox using the following steps:

1. Thermal noise removal
2. Radiometric calibration
3. Terrain correction using SRTM 30 or ASTER DEM for areas greater than 60 degrees latitude, where SRTM is not available. The final terrain-corrected values are converted to decibels via log scaling (10*log10(x)).

For more information about these pre-processing steps, please refer to the Sentinel-1 Pre-processing article. For further advice on working with Sentinel-1 imagery, see Guido Lemoine's tutorial on SAR basics and Mort Canty's tutorial on SAR change detection.

This collection is computed on-the-fly. If you want to use the underlying collection with raw power values (which is updated faster), see COPERNICUS/S1_GRD_FLOAT.

Bands

Bands

Name	Units	Min	Max	Pixel Size	Description
HH	dB	-50*	1*	10 meters	Single co-polarization, horizontal transmit/horizontal receive
HV	dB	-50*	1*	10 meters	Dual-band cross-polarization, horizontal transmit/vertical receive
VV	dB	-50*	1*	10 meters	Single co-polarization, vertical transmit/vertical receive
VH	dB	-50*	1*	10 meters	Dual-band cross-polarization, vertical transmit/horizontal receive
angle	deg	0*	90*	20000 meters	Approximate incidence angle from ellipsoid

* estimated min or max value

Image Properties

Image Properties

Name	Type	Description
GRD_Post_Processing_facility_country	STRING	Name of the country where the facility is located. This element is configurable within the IPF.
GRD_Post_Processing_facility_name	STRING	Name of the facility where the processing step was performed. This element is configurable within the IPF.
GRD_Post_Processing_facility_organisation	STRING	Name of the organisation responsible for the facility. This element is configurable within the IPF.
GRD_Post_Processing_facility_site	STRING	Geographical location of the facility. This element is configurable within the IPF.
GRD_Post_Processing_software_name	STRING	Name of the software.
GRD_Post_Processing_software_version	STRING	Software version identification.
GRD_Post_Processing_start	DOUBLE	Processing start time.
GRD_Post_Processing_stop	DOUBLE	Processing stop time.
SLC_Processing_facility_country	STRING	Name of the country where the facility is located. This element is configurable within the IPF.
SLC_Processing_facility_name	STRING	Name of the facility where the processing step was performed. This element is configurable within the IPF.
SLC_Processing_facility_organisation	STRING	Name of the organisation responsible for the facility. This element is configurable within the IPF.
SLC_Processing_facility_site	STRING	Geographical location of the facility. This element is configurable within the IPF.
SLC_Processing_software_name	STRING	Name of the software.
SLC_Processing_software_version	STRING	Software version identification.
SLC_Processing_start	DOUBLE	Processing start time.
SLC_Processing_stop	DOUBLE	Processing stop time.
S1TBX_Calibration_Operator_version	STRING	Sentinel-1 Toolbox calibration tool version.
S1TBX_SAR_Processing_version	STRING	Sentinel-1 Toolbox SAR processing tool version.
SNAP_Graph_Processing_Framework_GPF_version	STRING	Sentinel Application Platform (SNAP) version.
startTimeANX	DOUBLE	Sensing start time of the input data relative to the ascending node crossing. This is a count of the time elapsed since the orbit ascending node crossing [ms].
stopTimeANX	DOUBLE	Sensing stop time of the input data relative to the ascending node crossing. This is a count of the time elapsed since the orbit ascending node crossing [ms].
nssdcIdentifier	STRING	Uniquely identifies the mission according to standards defined by the World Data Center for Satellite Information (WDC-SI), available here.
familyName	STRING	The full mission name. E.g. "SENTINEL-1"
platform_number	STRING	The alphanumeric identifier of the platform within the mission.
platformHeading	DOUBLE	Platform heading relative to North, degrees
instrument	STRING	Information related to the instrument on the platform to which acquired the data.
instrumentMode	STRING	IW (Interferometric Wide Swath), EW (Extra Wide Swath) or SM (Strip Map)
instrumentSwath	STRING	List of the swaths contained within a product. Most products will contain only one swath, except for TOPS SLC products which include 3 or 5 swaths.
orbitNumber_start	DOUBLE	Absolute orbit number of the oldest line within the image data.
orbitNumber_stop	DOUBLE	Absolute orbit number of the most recent line within the image data.
relativeOrbitNumber_start	DOUBLE	Relative orbit number of the oldest line within the image data.
relativeOrbitNumber_stop	DOUBLE	Relative orbit number of the most recent line within the image data.
cycleNumber	DOUBLE	Absolute sequence number of the mission cycle to which the oldest image data applies.
phaseIdentifier	DOUBLE	Id of the mission phase to which the oldest image data applies.
orbitProperties_pass	STRING	Direction of the orbit ('ASCENDING' or 'DESCENDING') for the oldest image data in the product (the start of the product).
orbitProperties_ascendingNodeTime	DOUBLE	UTC time of the ascending node of the orbit. This element is present for all products except ASAR L2 OCN products which are generated from an ASAR L1 input.
resolution	STRING	H for high or M for medium.
resolution_meters	DOUBLE	Resolution in meters.
instrumentConfigurationID	DOUBLE	The instrument configuration ID (Radar database ID) for this data.
missionDataTakeID	DOUBLE	Unique ID of the datatake within the mission.
transmitterReceiverPolarisation	STRING_LIST	Transmit/Receive polarisation for the data. There is one element for each Tx/Rx combination: ['VV'], ['HH'], ['VV', 'VH'], or ['HH', 'HV'].
productClass	STRING	Output product class "A" for Annotation or "S" for Standard.
productClassDescription	STRING	Textual description of the output product class.
productComposition	STRING	The composition type of this product: "Individual", "Slice", or "Assembled".
productType	STRING	The product type (correction level) of this product.
productTimelinessCategory	STRING	Describes the required timeliness of the processing. One of: NRT-10m, NRT-1h, NRT-3h, Fast-24h, Off-line, or Reprocessing
sliceProductFlag	STRING	True if this is a slice from a larger product or false if this is a complete product.
segmentStartTime	DOUBLE	Sensing start time of the segment to which this slice belongs. This field is only present if sliceProductFlag = true
sliceNumber	DOUBLE	Absolute slice number of this slice starting at 1. This field is only present if sliceProductFlag = true.
totalSlices	DOUBLE	Total number of slices in the complete data take. This field is only present if sliceProductFlag = true.

Terms of Use

Terms of Use

The use of Sentinel data is governed by the Copernicus Sentinel Data Terms and Conditions.

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Code Editor (JavaScript)

var imgVV = ee.ImageCollection('COPERNICUS/S1_GRD')
        .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))
        .filter(ee.Filter.eq('instrumentMode', 'IW'))
        .select('VV')
        .map(function(image) {
          var edge = image.lt(-30.0);
          var maskedImage = image.mask().and(edge.not());
          return image.updateMask(maskedImage);
        });

var desc = imgVV.filter(ee.Filter.eq('orbitProperties_pass', 'DESCENDING'));
var asc = imgVV.filter(ee.Filter.eq('orbitProperties_pass', 'ASCENDING'));

var spring = ee.Filter.date('2015-03-01', '2015-04-20');
var lateSpring = ee.Filter.date('2015-04-21', '2015-06-10');
var summer = ee.Filter.date('2015-06-11', '2015-08-31');

var descChange = ee.Image.cat(
        desc.filter(spring).mean(),
        desc.filter(lateSpring).mean(),
        desc.filter(summer).mean());

var ascChange = ee.Image.cat(
        asc.filter(spring).mean(),
        asc.filter(lateSpring).mean(),
        asc.filter(summer).mean());

Map.setCenter(5.2013, 47.3277, 12);
Map.addLayer(ascChange, {min: -25, max: 5}, 'Multi-T Mean ASC', true);
Map.addLayer(descChange, {min: -25, max: 5}, 'Multi-T Mean DESC', true);

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

import ee
import geemap.core as geemap

Colab (Python)

def mask_edge(image):
  edge = image.lt(-30.0)
  masked_image = image.mask().And(edge.Not())
  return image.updateMask(masked_image)


img_vv = (
    ee.ImageCollection('COPERNICUS/S1_GRD')
    .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV'))
    .filter(ee.Filter.eq('instrumentMode', 'IW'))
    .select('VV')
    .map(mask_edge)
)

desc = img_vv.filter(ee.Filter.eq('orbitProperties_pass', 'DESCENDING'))
asc = img_vv.filter(ee.Filter.eq('orbitProperties_pass', 'ASCENDING'))

spring = ee.Filter.date('2015-03-01', '2015-04-20')
late_spring = ee.Filter.date('2015-04-21', '2015-06-10')
summer = ee.Filter.date('2015-06-11', '2015-08-31')

desc_change = ee.Image.cat(
    desc.filter(spring).mean(),
    desc.filter(late_spring).mean(),
    desc.filter(summer).mean(),
)

asc_change = ee.Image.cat(
    asc.filter(spring).mean(),
    asc.filter(late_spring).mean(),
    asc.filter(summer).mean(),
)

m = geemap.Map()
m.set_center(5.2013, 47.3277, 12)
m.add_layer(asc_change, {'min': -25, 'max': 5}, 'Multi-T Mean ASC', True)
m.add_layer(desc_change, {'min': -25, 'max': 5}, 'Multi-T Mean DESC', True)
m

Open in Code Editor

Sentinel-1 SAR GRD: C-band Synthetic Aperture Radar Ground Range Detected, log scaling

The Sentinel-1 mission provides data from a dual-polarization C-band Synthetic Aperture Radar (SAR) instrument at 5.405GHz (C band). This collection includes the S1 Ground Range Detected (GRD) scenes, processed using the Sentinel-1 Toolbox to generate a calibrated, ortho-corrected product. The collection is updated daily. New assets are ingested within two …

COPERNICUS/S1_GRD, copernicus,esa,eu,radar,sar,sentinel

2014-10-03T00:00:00Z/2024-11-21T17:19:56Z

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https://developers.google.com/earth-engine/datasets