GHRSST MUR sea surface temperature as COGs
Every day since 2002-06-01 of the GHRSST Level 4 MUR global foundation sea surface temperature analysis (v4.1), repackaged as Cloud Optimised GeoTIFFs (COGs) with a STAC item per day and a STAC GeoParquet index of all days. The data are public on Source Cooperative, need no login, and are kept up to date by a daily job.
The values are the source values. Each NetCDF variable becomes one COG per day, stored as the same integers with nodata, scale and offset in the metadata, on an exact north-up 0.01 degree grid. (For analysed_sst the offset gives degrees Celsius, where the source’s gives Kelvin; see Values and units.)
What changes is the packaging: any tool that reads a GeoTIFF over HTTP can read just the part of the world, and the resolution, it needs.
Contents
| Page | Covers |
|---|---|
| Background | Motivation, and the move from a local file cache to a public cloud copy |
| The data | File layout, grid, variables, units and STAC fields |
| Python | odc-stac, rasterio, rustac, DuckDB |
| R | terra, gdalraster, vapour, stars, arrow |
| Other tools | GDAL command line, DuckDB, QGIS, the browser |
| Virtual stores | The daily COGs as one cube, now and with the coming indexes |
| How it’s made | Conversion, infrastructure, and how days are kept final |
In one minute
The analysed_sst COG for any day follows a template:
https://data.source.coop/ausantarctic/ghrsst-mur-v2/{YYYY}/{MM}/{DD}/{YYYYMMDD}090000-JPL-L4_GHRSST-SSTfnd-MUR-GLOB-v02.0-fv04.1_analysed_sst.tif
With GDAL (any language that wraps it):
gdal raster info /vsicurl/https://data.source.coop/ausantarctic/ghrsst-mur-v2/2025/06/01/20250601090000-JPL-L4_GHRSST-SSTfnd-MUR-GLOB-v02.0-fv04.1_analysed_sst.tif
The index of every day, with each day’s status (final, preliminary or nrt_only):
https://data.source.coop/ausantarctic/ghrsst-mur-v2/ghrsst-mur-v2.parquet
Or look at a day in the browser, in any projection, with ortho-cog-viewer.
Preliminary and final
MUR publishes each day twice: a near-real-time (NRT) version about a day after the date, then a final version, usually about 9 days after, that replaces it. New days here are converted from the NRT version and re-converted when the final lands. Every STAC item says which it is, in ghrsst:status. For research that needs the final analysis, filter on ghrsst:status = 'final'. See The data.
Virtual stores
Indexes over the same COGs, so the whole archive opens as one array without copying any data. A GDAL multidimensional VRT is published now; a flat tabular index of every tile, a kerchunk Parquet reference store and an Icechunk store are coming. See Virtual stores.
Source and citation
The source is the GHRSST Level 4 MUR Global Foundation Sea Surface Temperature Analysis (v4.1) from NASA JPL, distributed by PO.DAAC, doi:10.5067/GHGMR-4FJ04. Please cite the source dataset as PO.DAAC asks in Citing PO.DAAC. Data hosted by PO.DAAC is openly shared, without restriction, in accordance with NASA’s Earth Science program Data and Information Policy.