Global Seasonal Sentinel-1 Interferometric Coherence and Backscatter Dataset

This dataset is the first-of-its-kind spatial representation of multi-seasonal, global SAR repeat-pass interferometric coherence and backscatter signatures. Global coverage comprises all land masses and ice sheets from 82 degrees northern to 78 degrees southern latitude. The dataset is derived from high-resolution multi-temporal repeat-pass interferometric processing of about 205,000 Sentinel-1 Single-Look-Complex (SLC) data acquired in Interferometric Wide-Swath mode (Sentinel-1 IW mode) from 1-Dec-2019 to 30-Nov-2020.

The dataset was developed by Earth Big Data LLC and Gamma Remote Sensing AG, under contract for NASA’s Jet Propulsion Laboratory.

The dataset covers seasonal (DJF/MAM/JJA/SON) metrics of:

Median 6-, 12-, 18-, 24-, 36-, and 48-day repeat coherence estimates for C-band VV and HH polarized data
Mean backscatter (γ $γ^{0}$ for VV, VH, HH, and HV polarizations
Seasonal coherence decay model parameters rho, tau, and rmse
Local incidence and layover/shadow regions for all relative Sentinel-1A and Sentinel-1B orbits. Note that in the dataset filenames seasons were referred to as northern hemisphere winter (DJF), spring (MAM), summer (JJA), and fall (SON).

Overview

User Guide/Technical Information

Products

License and Data Citation

Resources

Overview

Dataset Property	Value
Spatial Coverage:	N: 82, S: -78, E: 180, W: -180
Spatial Resolution:	3 arcseconds
Temporal Coverage:	1 Dec 2019 to 30 Nov 2020
Temporal Resolution:	6 to 48 days
Parameters:
Data Format:	GeoTiff
Platform:	Sentinel-1
Instrument:	C-SAR

Expand the sections below to view content. Access the full content on a single page by clicking the button.

User Guide/Technical Information

For a full description of the data set please refer to “Global seasonal Sentinel-1 interferometric coherence and backscatter data set”. Josef Kellndorfer, Oliver Cartus, Marco Lavalle, Christophe Magnard, Pietro Mililo, Shadi Oveisgharan, Batu Osmanoglu, Paul Rosen, Urs Wegmüller. doi: 10.1038/s41597-022-01189-6 (opens in new tab)

Data Records

The dataset contains three main data records:

1. 1 x 1-degree tiles. Each tile contains GeoTIFFs at 3 arcsec pixel spacing of all metrics available in the tile.

2. Global Virtual Raster Tables (VRT) with external overview files of seasonal backscatter, coherence, rho, tau, and rmse including VRT stacks of seasons.

3. Global mosaicked tiles as cloud optimized GeoTIFFs at 0.01-degree pixel spacing for eachof the computed metrics

Naming and Organization of 1 x 1-degree tile data

The 1 x 1 degree tiles of the data set form the basic units of produced image data. All computed metrics are stored as image files in GeoTIFF format where the extent of the images covers exactly 1 degree in longitude and 1 degree in latitude with the origin of the upper left pixel at a full degree in latitude and longitude respectively. All GeoTIFFs have 3 arcseconds resolution in both dimensions and are output to a geographic reference system based on the WGS84 ellipsoid (EPSG:4326). Thus, each file in a tile has a raster dimension of 1,200 pixels by 1,200 lines. For all images, no data values are coded as the digital number zero. Global coverage encompasses a total number of 25,334 tiles.

Tile naming convention
- Tile identifiers (TILEID) in the data set are labeled by the upper left coordinate of each 1×1 degree tile using North (N) and South (S), and East (E) and West (W) qualifiers.
- Examples
  - N48W090 covers the area of 47°-48° northern latitude and 90°-89° degrees western longitude
  - S01E012 covers the area of 1°-2° southern latitude and 12°-13° degrees eastern longitude

File naming convention for backscatter, coherence, and model parameter files
- <TILEID>_<SEASON>_<POLARIZATION>_<METRIC>.tif
  - TILEID = Identifier of tile referenced to upper left tile corner
  - SEASON = winter, spring, summer, or fall (referring to Northern hemisphere seasons)
  - POLARIZATION = vv, vh, hh, or hv
  - METRIC = AMP, COHxx, rho, tau, rmse
    - xx = 06, 12, 18, 24, 36, 48
- Examples
  - N49E012_winter_vv_COH06.tif
  - N49E012_spring_vv_COH48.tif
  - N49E012_summer_vh_AMP.tif

File naming convention for incidence angle and layover/shadow files
- <TILEID>_<000><F>_<METRIC>.tif
  - TILEID = Identifier of tile referenced to upper left tile corner
  - 000 = Relative orbit number from 001 to 175
  - F = A or D for ascending or descending flight direction
  - METRIC = inc or lsmap
- Example
  - N49E012_095D_inc.tif

Tiles in the dataset are labeled by the upper left coordinate of each 1×1 degree tile. Each tile contains the following metrics (based on available polarization covering a tile) as a GeoTiff file.

Winter
winter_vv_AMP	winter_hh_AMP
winter_vh_AMP	winter_hv_AMP
winter_vv_COH06	winter_hh_COH06
winter_vv_COH12	winter_hh_COH12
winter_vv_COH18	winter_hh_COH18
winter_vv_COH24	winter_hh_COH24
winter_vv_COH36	winter_hh_COH36
winter_vv_COH48	winter_hh_COH48
winter_vv_rho	winter_hh_rho
winter_vv_rmse	winter_hh_rmse
winter_vv_tau	winter_hh_tau
Spring
spring_vv_AMP	spring_hh_AMP
spring_vh_AMP	spring_hv_AMP
spring_vv_COH06	spring_hh_COH06
spring_vv_COH12	spring_hh_COH12
spring_vv_COH18	spring_hh_COH18
spring_vv_COH24	spring_hh_COH24
spring_vv_COH36	spring_hh_COH36
spring_vv_COH48	spring_hh_COH48
spring_vv_rho	spring_hh_rho
spring_vv_rmse	spring_hh_rmse
spring_vv_tau	spring_hh_tau
Summer
summer_vv_AMP	summer_hh_AMP
summer_vh_AMP	summer_hv_AMP
summer_vv_COH06	summer_hh_COH06
summer_vv_COH12	summer_hh_COH12
summer_vv_COH18	summer_hh_COH18
summer_vv_COH24	summer_hh_COH24
summer_vv_COH36	summer_hh_COH36
summer_vv_COH48	summer_hh_COH48
summer_vv_rho	summer_hh_rho
summer_vv_rmse	summer_hh_rmse
summer_vv_tau	summer_hh_tau
Fall
fall_vv_AMP	fall_hh_AMP
fall_vh_AMP	fall_hv_AMP
fall_vv_COH06	fall_hh_COH06
fall_vv_COH12	fall_hh_COH12
fall_vv_COH18	fall_hh_COH18
fall_vv_COH24	fall_hh_COH24
fall_vv_COH36	fall_hh_COH36
fall_vv_COH48	fall_hh_COH48
fall_vv_rho	fall_hh_rho
fall_vv_rmse	fall_hh_rmse
fall_vv_tau	fall_hh_tau

Data Conversion to Digital Numbers (Tile Data)

List of GeoTIFF image products and data conversion to digital numbers in a tile. No data value for all products is the digital number zero (0).

Metric		Format
Mean seasonal backscatter amplitudes γ⁰ (AMP)	Polarizations: HH, VV, HV, VH	Scaled to 16bit unsigned interger with: DN=10.0^((dB+83.0)/20.0) where: dB= 10*log10(γ⁰)
Median seasonal 6,12,18,24,36,48-days repeat-pass coherences (COHxx)	Polarizations: HH, VV	Coherence ρ scaled to 8bit unsigned integer with: DN=ρ*100
Seasonal coherence decay-model parameters ρ_∞, τ, and RMSE (rho, tau, rmse)	Polarizations: HH, VV	ρ_∞, τ, RMSE scaled to 16bit unsigned integer with: DN= ρ_∞/τ/RMSE*1000
Local incidence angle (inc)	Per relative orbit	DN=Degrees (8bit unsigned integer)
Layover/shadow mask (lsmap)	Per relative orbit	8bit unsigned integer where: 1 – No Shadow or Layover 5 – Layover 17 – Shadow 21 – Shadow in Layover

Naming and Organization of Virtual Raster Tables

Virtual Raster Tables (VRT) are available for each seasonal mosaic of a given metric such as the 12-days coherence for the (northern hemisphere) summer or the mosaic of backscatter at VH polarization in winter. In addition, global VRTs are provided which contain all seasonal mosaics of a given metric.

For visualization purposes, external overviews were produced on these files at four overview levels reducing the full resolution global mosaic by two-dimensional down-sampling with averaging by factors of 3×3, 9×9, 27×27, and 81×81. The external overview files are identified by having a filename identical to the global mosaics with the additional postfix “.ovr” appended.

- File naming conventions for seasonal single metric VRTs
  - Global_<SEASON>_<POLARIZATION>_<METRIC>.vrt
    - SEASON = winter, spring, summer, or fall (referring to Northern hemisphere seasons)
    - POLARIZATION = vv, vh, hh, or hv
    - METRIC = AMP, COHxx, rho, tau, rmse
      - xx = 06, 12, 18, 24, 36, 48
  - Examples
    - Global_spring_vv_COH06.vrt
    - Global_winter_vh_AMP.vrt
- File naming conventions for all-season VRT stacks
  - Global__<POLARIZATION>_<METRIC>.vrt
    - POLARIZATION = vv, vh, hh, or hv
    - METRIC = AMP, COHxx, rho, tau, rmse
      - xx = 06, 12, 18, 24, 36, 48
  - Examples
    - Global__vv_COH06.vrt
    - Global__hh_AMP.vrt

Naming and Organization of global GeoTiff Mosaics with 0.01-degree sample spacing

From the global VRTs, downsampled cloud-optimized GeoTIFFs (COG) were generated with built-in overviews. Sample spacing in these mosaics are 0.01 degrees on both longitudinal and latitudinal directions.

File naming convention for global 0.01-degree sample spacing GeoTiffs
- Global_<SEASON>_<POLARIZATION>_<METRIC>_100ppd.tif
  - SEASON = winter, spring, summer, or fall (referring to Northern hemisphere seasons)
  - POLARIZATION = vv, vh, hh, or hv
  - METRIC = AMP, COHxx, rho, tau, rmse
    - xx = 06, 12, 18, 24, 36, 48
- Examples
  - Global_spring_vv_COH06_100ppd.tif
  - Global_fall_vv_rho_100ppd.tif

Download Tile Data

Each file in a tile is available via a https url link.

URLs can be constructed by adding the prefix https://sentinel1.asf.alaska.edu/global_coherence/s1/tiles/ to the file naming convention for the 1 x1-degree tiles.

Example URL:

https://sentinel1.asf.alaska.edu/global_coherence/s1/tiles/N42W090/N42W090_092A_lsmap.tif

https://sentinel1.asf.alaska.edu/global_coherence/s1/tiles/N00E005/N00E005_124D_inc.tif

https://sentinel1.asf.alaska.edu/global_coherence/s1/tiles/N00E005/N00E005_fall_vv_COH36.tif

Alternatively, the table below provides Excel files batched by tile latitude which contain individual file links.

Latitude Range	Download File
00 – 09 North	Sentinel-1_Coherence_Tiles_N00-09_FileList
10 – 19 North	Sentinel-1_Coherence_Tiles_N10-19_FileList
20 – 29 North	Sentinel-1_Coherence_Tiles_N20-29_FileList
30 – 39 North	Sentinel-1_Coherence_Tiles_N30-39_FileList
40 – 49 North	Sentinel-1_Coherence_Tiles_N40-49_FileList
50 – 59 North	Sentinel-1_Coherence_Tiles_N50-59_FileList
60 – 69 North	Sentinel-1_Coherence_Tiles_N60-69_FileList
70 – 79 North	Sentinel-1_Coherence_Tiles_N70-79_FileList
80 – 82 North	Sentinel-1_Coherence_Tiles_N80-82_FileList
01 – 09 South	Sentinel-1_Coherence_Tiles_S01-09_FileList
10 – 19 South	Sentinel-1_Coherence_Tiles_S10-19_FileList
20 – 29 South	Sentinel-1_Coherence_Tiles_S20-29_FileList
30 – 39 South	Sentinel-1_Coherence_Tiles_S30-39_FileList
40 – 49 South	Sentinel-1_Coherence_Tiles_S40-49_FileList
50 – 57 South	Sentinel-1_Coherence_Tiles_S50-57_FileList
60 – 69 South	Sentinel-1_Coherence_Tiles_S60-69_FileList
70 – 78 South	Sentinel-1_Coherence_Tiles_S70-78_FileList

Download Virtual Raster Tables

Download links for the global virtual raster tables are provided as a csv file, Sentinel-1_Coherence_Global_VRT_FileList

Download Global Mosaics

Citation Information

License

The use of these data fall under the terms and conditions of the Creative Commons Attribution 4.0 International Public License

Contains modified Copernicus Sentinel data.

Data Citation

As a condition of using these data, please cite the use of this data set using the following citation.

Kellndorfer, J. , O. Cartus, M. Lavalle, C. Magnard, P. Milillo, S. Oveisgharan, B. Osmanoglu, P. Rosen, and U. Wegmüller. 2022. Global seasonal Sentinel-1 interferometric coherence and backscatter data set. [Indicate subset used]. Fairbanks, Alaska USA. NASA Alaska Satellite Facility Synthetic Aperture Radar Distributed Active Archive Center. doi: https://doi.org/10.5067/8W33RRS6S2RV. [Date Accessed].

Literature Citation

As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.

Resources

For information on how to access and use the Coherence and Backscatter Dataset Image Services available from ASF, view the StoryMap tutorial: Sentinel-1 Interferometric Coherence Image Services
“Enhancing access to the Global Seasonal Sentinel-1 Interferometric Coherence and Backscatter Dataset with Image Services”

Alaska Satellite Facility - Distributed Active Archive Center

Data

Resources

Tools

Get Data at ASF DAAC

Data Use

ASF Data Search – Vertex

SAR Datasets

Derived Datasets

Optical Datasets

ASF Dataset DOI’s

SAR Information

SAR Training

Glacier Power

ASF Data Terms of Use

Alaska Satellite Facility: Making remote-sensing data accessible.

The Alaska Satellite Facility

Global Seasonal Sentinel-1 Interferometric Coherence and Backscatter Dataset

Overview

User Guide/Technical Information

Download Tile Data

Download Virtual Raster Tables

Download Global Mosaics

Citation Information

License

Data Citation

Literature Citation

Resources