Documented Sentinel-1 SLC data

Author: agentmorris

README.md

@@ -283,14 +283,23 @@ Video data from the [Ocean Observatories Initiative](https://oceanobservatories.
 
 ## Sentinel-1 GRD
 
-Global synthetic aperture radar (SAR) data from 2017-present.
+Global synthetic aperture radar (SAR) data from 2017-present, projected to ground range.
 
 Sentinel-1 GRD data are in preview; access is granted by request.
 
 * [Source](https://sentinel.esa.int/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/ground-range-detected)
 * [Documentation](data/sentinel-1-grd.md)
 * [Notebook](https://nbviewer.jupyter.org/github/microsoft/AIforEarthDataSets/blob/main/data/sentinel-1-grd.ipynb)
 
+## Sentinel-1 SLC
+
+Global synthetic aperture radar (SAR) data for the last 90 days.
+
+Sentinel-1 SLC data are in preview; access is granted by request.
+
+* [Source](https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/single-look-complex)
+* [Documentation](data/sentinel-1-slc.md)
+
 ## Sentinel-2 L2A
 
 Global optical imagery at 10m resolution from 2016-present.

data/sentinel-1-grd.md

@@ -2,14 +2,15 @@
 
 ## Overview
 
-The [Sentinel-1](https://sentinel.esa.int/web/sentinel/missions/sentinel-1) program provides global synthetic aperature radar imaging with a revisit time of approximately six days.  The [Ground Range Detected](https://sentinel.esa.int/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/ground-range-detected) (GRD) product has been detected and projected to ground range.
+The [Sentinel-1](https://sentinel.esa.int/web/sentinel/missions/sentinel-1) program provides global synthetic aperture radar imaging with a revisit time of approximately six days.  The [Ground Range Detected](https://sentinel.esa.int/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/ground-range-detected) (GRD) product has been detected and projected to ground range.
 
 This dataset represents the global Sentinel-1 GRD archive, from 2017 to the present, converted to [cloud-optimized GeoTIFF](https://www.cogeo.org/) format.
 
 Sentinel-1 data on Azure are maintained by [Sinergise](https://sinergise.com/).
 
 Sentinel-1 GRD imagery is currently in preview on Azure; email [`aiforearthdatasets@microsoft.com`](mailto:aiforearthdatasets@microsoft.com?subject=sentinel1%20question) to request access.
 
+We also maintain a 90-day rolling window of Sentinel-1 SLC data, see the [SLC documentation](https://aka.ms/ai4edata-sentinel-1-slc).
 
 ## Storage resources
 

data/sentinel-1-slc.md

@@ -0,0 +1,74 @@
+# Sentinel-1 SLC
+
+## Overview
+
+The [Sentinel-1](https://sentinel.esa.int/web/sentinel/missions/sentinel-1) program provides global synthetic aperture radar imaging with a revisit time of approximately six days.  The [Single Look Complex](https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-algorithms/single-look-complex) (SLC) product includes images in the slant range, in the plane in which images are acquired.
+
+This dataset represents the most recent 90 days of the Sentinel-1 SLC archive, in the [SAFE](https://sentinels.copernicus.eu/web/sentinel/user-guides/sentinel-1-sar/data-formats/safe-specification) format in which images are provided by the European Space Agency.
+
+Sentinel-1 data on Azure are maintained by [Sinergise](https://sinergise.com/).
+
+Sentinel-1 SLC data is currently in preview on Azure; email [`aiforearthdatasets@microsoft.com`](mailto:aiforearthdatasets@microsoft.com?subject=sentinel1%20question) to request access.
+
+We also maintain a complete archive of Sentinel-1 GRD data, in cloud-optimized format; see the [GRD documentation](https://aka.ms/ai4edata-sentinel-1).
+
+## Storage resources
+
+### Container information
+
+Data are stored in blobs in the West Europe Azure region, in the following blob container:
+
+`https://sentinelintake.blob.core.windows.net/s1-slc`
+
+
+### Scene names
+
+Within that container, each scene corresponds to a folder, named according to:
+
+`SLC/[year]/[month]/[day]/[acquisition-mode]/[polarization]/[scene_name]`
+
+* `year` is a four-digit year
+* `month` is the 1-indexed, non-zero-padded month
+* `day` is the 1-indexed, non-zero-padded day
+* `acquisition-mode` is the [acquisition mode](https://sentinels.copernicus.eu/web/sentinel/user-guides/sentinel-1-sar/acquisition-modes) for this scene, one of IW (interferometric wide swath), SM (stripmap), EW (extra-wide swath), or WV (wave)
+* `polarization` is the [polarization mode](https://sentinel.esa.int/web/sentinel/user-guides/sentinel-1-sar/product-overview/polarimetry) for this scene, typically one of SH (single HH), SV (single VV), DH (dual HH+HV), or DV (dual VV+VH); HH, HV, VV, and VH also occur
+
+`scene name` follows the [Sentinel-1 scene name convention](https://sentinel.esa.int/web/sentinel/technical-guides/sentinel-1-sar/products-algorithms/level-1-product-formatting):
+
+`MMM_BB_TTTR_LFPP_YYYYMMDDTHHMMSS_YYYYMMDDYHHMMSS_OOOOOO_DDDDDD_CCCC`
+
+* `MMM` is satellite (S1A or S1B)
+* `BB` is the acquisition mode
+* `TTT` is the product type (always `GRD` in this data set)
+* `L` is the processing level (always `1` in this data set)
+* `F` is the product class (always `S` (for "SAR standard") in this dataset)
+* `PP` is the polarization (SH, SV, DH, DV, HH, HV, VV, or VH)
+* `YYYYMMDDTHHMMSS_YYYYMMDDTHHMMSS` is the scene start and stop capture time
+* `OOOOOO` is an absolute orbit number
+* `DDDDDD` is the "mission data take identifier" 
+* `CCCC` is a checksum
+
+Putting that all together, a complete scene file looks like:
+
+`https://sentinelintake.blob.core.windows.net/s1-slc/SLC/2021/10/7/IW/SH/S1A_IW_SLC__1SSH_20211007T012134_20211007T012201_040006_04BC4B_7D74.zip`
+
+
+### Data archiving
+
+Scenes older than 90 days are stored in the same container, but have been retired to [Azure archive storage](https://azure.microsoft.com/en-us/services/storage/archive/#overview).  Those scenes will still be enumerated when listing blobs in the container, but they will not be readable with read-only access tokens.
+
+
+## Region information
+
+Large-scale processing is best performed in the West Europe Azure region, where the images are stored.  If you are using Sentinel-1 data for environmental science applications, consider applying for an [AI for Earth grant](http://aka.ms/ai4egrants) to support your compute requirements.
+
+
+## Contact
+
+For questions about this dataset, contact [`aiforearthdatasets@microsoft.com`](mailto:aiforearthdatasets@microsoft.com?subject=sentinel-1%20question).
+
+
+## Notices
+
+Microsoft provides this dataset on an "as is" basis.  Microsoft makes no warranties (express or implied), guarantees, or conditions with respect to your use of the dataset.  To the extent permitted under your local law, Microsoft disclaims all liability for any damages or losses - including direct, consequential, special, indirect, incidental, or punitive - resulting from your use of this dataset.  This dataset is provided under the original terms that Microsoft received source data.
+

data/uk-met-20crds.md

@@ -12,7 +12,7 @@ This data is made available under the [Open Government License version 2](http:/
 
 ## About the data
 
-This dataset covers the whole of China for the period 1851 to 2010 at a horizontal resolution of 25 km. For more details see <a href=https://journals.ametsoc.org/view/journals/apme/58/10/jamc-d-19-0083.1.xml> Amato et al, 2019</a>.
+This dataset covers the whole of China for the period 1851 to 2010 at a horizontal resolution of 25 km. For more details see <a href="https://journals.ametsoc.org/view/journals/apme/58/10/jamc-d-19-0083.1.xml">Amato et al, 2019</a>.
 
 The dataset include monthly, daily, three-hourly, and hourly frequencies for the historical period of 1851-2010. Data are stored in <a href="https://zarr.readthedocs.io/en/stable/">Zarr</a> format and contain the following variables: