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Full catalog/REYNOLDS_NCDC_L4_MONTHLY_V5
REYNOLDS_NCDC_L4_MONTHLY_V5·v5·dataset

How warm the sea surface is, monthly (reconstructed, ERSST)

NOAA Smith and Reynolds Extended Reconstructed Sea Surface Temperature (ERSST) Level 4 Monthly Version 5 Dataset in netCDF
ocean NASA POCLOUD Level 4 netCDF-4
In plain English

What it measures. A month-by-month record of how warm the global ocean surface has been, and how far that strays from normal, stretching all the way back to 1854 on a coarse worldwide grid.

How it's made. It's a statistical reconstruction: ship, buoy, and float measurements are blended and gap-filled with a consistent method to fill in places and times with sparse data.

How & where you'd use it. A go-to reference for studying long-term ocean warming, climate variability like El Nino, and how sea surface temperatures have shifted over more than a century and a half.

What's measured

OCEANS › OCEAN TEMPERATURE › SEA SURFACE TEMPERATURE RECONSTRUCTION

Coverage & cadence

  • Time span1854-01-01 → ongoing
  • Measured byNCEP GTS (DRIFTING BUOYS) · SHIPS (THERMISTORS)
  • Processing levelLevel 4
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • StatusACTIVE

What you can do with it

  • Watch sea-surface temperature and marine heatwaves
  • Spot algal blooms and ocean-colour shifts
  • Support fisheries and coastal monitoring
Official description

The Smith & Reynolds Extended Reconstructed Sea Surface Temperature (ERSST) Level 4 dataset provides a historical reconstruction of monthly global ocean surface temperatures and temperature anomalies over a 2 degree spatial grid since 1854 from in-situ observations based on a consistent statistical methodology that accounts for uneven sampling distributions over time and related observational biases. Version 5 of this dataset implements release 3.0 of ICOADS (International Comprehensive Ocean-Atmosphere Data Set) and is supplemented by monthly GTS (Global Telecommunications Ship and buoy) system data. As for the prior ERSST version, v5 implements Empirical Orthogonal Teleconnection analysis (EOT) but with an improved tuning method for sparsely sampled regions and periods. ERSST anomalies are computed with respect to a 1971-2000 monthly climatology. The version 5 has been improved from previous version 4. Major improvements in v5 include: 1) Inclusion and use of new sources and new versions of input datasets, such as data from Argo floats (new source), ICOADS R3.0 (from R2.5), HadISST2 (from HadISST1) sea ice concentration, and 2) Improved methodologies, such as inclusion of additional statistical modes, less spatial-temporal smoothing, better quality control method, and bias correction with baseline to modern buoy observations. The new version improves the spatial structures and magnitudes of El Nino and La Nina events. The ERSST v5 in netCDF format contains extended reconstructed sea surface temperature, SST anomaly, and associated estimated SST error standard deviation fields, in compliance with CF1.6 standard metadata.

Get the data

reynolds_ncdc_l4_monthly_v5_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="REYNOLDS_NCDC_L4_MONTHLY_V5",
    version="5",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from POCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.