Download the observations that ECCO Version 4 Release 4 (V4r4) used to constrain the ocean/sea-ice state estimate. Those files are published on NASA Earthdata / PO.DAAC as the ancillary collection ECCO_L4_ANCILLARY_DATA_V4R4 (DOI 10.5067/ECCL4-ANC44).

The collection has eight tar granules. Only one of them is the observations: ancillary_data_data_constraints_ECCO_V4r4.tar.gz (~9.1 GiB compressed). That is the default download. The other tars are documentation, initial conditions, forcing, native-grid binaries, or model-equivalent in-situ profiles — not the observations themselves.

What is in data_constraints

After extract, the tree is data_constraints/ on the LLC90 native grid (binary, 90×1170). See the PO.DAAC data-constraints README.

Directory Constraint
input_sla Daily RADS altimetry SSH
input_sst Reynolds daily AVHRR SST
input_sss Aquarius monthly SSS
input_bp Monthly GRACE JPL RL05 ocean bottom pressure
input_seaice_conc Daily NSIDC SSM/I–SSMIS sea-ice concentration
input_insitu Argo / CTD / XBT / glider / mooring / ITP profiles
input_other WOA'09 climatology, DTU17MDT, global-mean SSH and OBP
data_error Observation errors and smoothing scales

Most of those source archives are not on PO.DAAC (RADS, NSIDC, Argo GDAC, WOA). Aquarius and GRACE mascons are. The ancillary tar is the official PO.DAAC copy of the exact files ECCO assimilated, so this package downloads that rather than re-pulling every upstream mission.

V4r4 covers 1992-01-01 … 2018-01-01. A later V4r5 ancillary observations collection is not published on PO.DAAC as of this writing.

CLI

# Plan (CMR search + manifest, no transfer, no Earthdata login)
odsl-ecco-download --dry-run
odsl-ecco-download --list

# Download the observations (~9.1 GiB) and extract data_constraints/
odsl-ecco-download --jobs 1 --verify size

# Also fetch the small documentation tar
odsl-ecco-download --granules data_constraints doc

# Leave the tar packed
odsl-ecco-download --no-extract

Shared flags: --dry-run, --jobs, --verify {none,size,checksum}, --overwrite, --retries, --timeout, --limit, --out-dir.

--all-ancillary pulls every tar, including ~290 GiB of forcing. Do not use that unless you intend to reproduce the model run.

Layout

Constant: DEFAULT_ECCO_ROOT (ecco/utils.py) = /spray/ecco.

/spray/ecco/raw/ECCO_L4_ANCILLARY_DATA_V4R4/ancillary_data_data_constraints_ECCO_V4r4.tar.gz
/spray/ecco/data_constraints/{input_sla,input_sst,input_sss,input_bp,...}
/spray/ecco/catalog/ecco_observations_manifest.{csv,json}

Existing V4r4 0.5° model output under /spray/ecco/v4r4-0.5deg/ is left alone.

Authentication

NASA Earthdata Login (urs.earthdata.nasa.gov) via ~/.netrc or EARTHDATA_USERNAME / EARTHDATA_PASSWORD. Same convention as SWOT / PACE / ICESat-2.

machine urs.earthdata.nasa.gov login <username> password <password>

Tests

pytest ecco/tests

No /spray required. Discovery, dest paths, manifest, and extract are exercised against a CMR UMM fixture.