This high-resolution sea surface temperature (SST) analysis product was developed using an optimum interpolation (OI) technique. The OISST analysis has a spatial grid resolution of 0.25 degree and temporal resolution of 1 day, spanning from September 1981 to present. The analysis was constructed by combining observations from different platforms on a regular global grid, including Advanced Very High Resolution Radiometer (AVHRR) satellite data, ships, buoys and Argo floats. A spatially complete SST map was produced by interpolating to fill in spatial gaps. The methodology includes bias adjustment of satellite and ship observations (referenced to buoys) to compensate for platform differences and sensor biases. This proved critical during the Mt. Pinatubo eruption in 1991, when the widespread presence of volcanic aerosols resulted in infrared satellite temperatures that were much cooler than actual ocean temperatures, and other degradation of satellite observations. Released in March 2020, Version 2.1 supersedes the previous Version 2. For the January 2016 to present time period, changes include: 1) In-Situ ship and buoy data changed from the NCEP Traditional Alphanumeric Codes (TAC) to the NCEI merged TAC + Binary Universal Form for the Representation (BUFR) data; 2) Addition of Argo float observed SST data; 3) Satellite input changed from METOP-A and NOAA-19 to METOP-A and METOP-B; 4) Revised ship-buoy SST corrections and revised sea-ice-concentration to SST conversion. The data before January 1, 2016 remain the same as Version 2.0. Preliminary product files are produced daily in near real-time (1-day latency) and can be updated in the first few days if critical input data become available after the initial production time. After two weeks, a complete or final product is generated and archived with no additional changes expected. The product is available in netCDF-4 with metadata attributes.

The NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (or daily OISST) is an analysis constructed by combining observations from different platforms (satellites, ships, buoys) on a regular global grid. A spatially complete SST map is produced by interpolating to fill in gaps. Data starts in 1981 and is updated to near present.

NOAA/National Centers for Environmental Information (NCEI) 1/4 Degree Daily Optimum Interpolation Sea Surface Temperature (OISST) Analysis, Version 2.1. Reynolds, et al.(2007) Daily High-Resolution-Blended Analyses for Sea Surface Temperature (available at https://doi.org/10.1175/2007JCLI1824.1). Banzon, et al.(2016) A long-term record of blended satellite and in situ sea-surface temperature for climate monitoring, modeling and environmental studies (available at https://doi.org/10.5194/essd-8-165-2016). Huang, B., C. Liu, V. Banzon, E. Freeman, G. Graham, B. Hankins, T. Smith, and H.-M. Zhang, 2021: Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1 (available at https://doi.org/10.1175/Journal of Climate (JCLI)-D-20-0166.1). Anomaly is based on 1971-2000 OI.v2 SST. Satellite data: multi-satellite sensor (Advanced Very High Resolution Radiometer (AVHRR)+Visible and Infrared Imager/Radiometer Suite (VIIRS)) data. Ice data: National Centers for Environmental Prediction (NCEP) Ice and Goddard Space Flight Center (GSFC) Ice. Data less than 15 days old may be subject to revision. cdm_data_type=Grid comment=Reynolds, et al.(2007) Daily High-Resolution-Blended Analyses for Sea Surface Temperature (available at https://doi.org/10.1175/2007JCLI1824.1). Banzon, et al.(2016) A long-term record of blended satellite and in situ sea-surface temperature for climate monitoring, modeling and environmental studies (available at https://doi.org/10.5194/essd-8-165-2016). Huang, B., C. Liu, V. Banzon, E. Freeman, G. Graham, B. Hankins, T. Smith, and H.-M. Zhang, 2021: Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1 (available at https://doi.org/10.1175/JCLI-D-20-0166.1). Anomaly is based on 1971-2000 OI.v2 SST. Satellite data: multi-satellite sensor (AVHRR+VIIRS) data. Ice data: NCEP Ice and GSFC Ice. Data less than 15 days old may be subject to revision. Conventions=CF-1.10, COARDS, ACDD-1.3 dataset_title=NOAA Daily Optimum Interpolation Sea Surface Temperature Easternmost_Easting=359.875 geospatial_lat_max=89.875 geospatial_lat_min=-89.875 geospatial_lat_resolution=0.25 geospatial_lat_units=degrees_north geospatial_lon_max=359.875 geospatial_lon_min=0.125 geospatial_lon_resolution=0.25 geospatial_lon_units=degrees_east history=NOAA/NCEI https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/ infoUrl=https://www.psl.noaa.gov/data/gridded/data.noaa.oisst.v2.highres.html institution=NOAA | National Centers for Environmental Information keywords_vocabulary=GCMD Science Keywords Northernmost_Northing=89.875 not_missing_threshold_percent=minimum 3% values input to have non-missing output value references=https://www.psl.noaa.gov/data/gridded/data.noaa.oisst.v2.highres.html source=NOAA/NCEI https://www.ncei.noaa.gov/data/sea-surface-temperature-optimum-interpolation/v2.1/access/avhrr/ sourceUrl=https://www.psl.noaa.gov/thredds/dodsC/Datasets/noaa.oisst.v2.highres/sst.mon.ltm.1991-2020.nc Southernmost_Northing=-89.875 standard_name_vocabulary=CF Standard Name Table v70 time_coverage_end=0001-12-01T00:00:00Z time_coverage_start=0001-01-01T00:00:00Z version=Version 2.1 Westernmost_Easting=0.125

The following MATLAB .mat file ( sponge_data_oisst_v2.mat) contains daily records of sea surface temperature spanning 01 Jan 1992 to 31 May 2022 from 14 locations around the New Zealand coastline, extracted from the OISST data set (https://doi.org/10.25921/RE9P-PT57), as analysed in Bell et al. (2022).

Also included are MATLAB .m files to (1) extract daily time series of SST from a local copy of the global OISST netcdf files (bell_etal_extract_OISST.m) and (2) undertake the analysis of marine heatwaves in the sponge_data_oisst_v2.mat subset of these data (bell_etal_analyze_OISST.m), as performed in Bell et al. (2022).

We acknowledge the NOAA OI SST V2 High Resolution Dataset provided by the NOAA PSL, Boulder, Colorado, USA, from their website at https://psl.noaa.gov

CNR MED Sea Surface Temperature provides daily gap-free maps (L4) at 0.0625 deg. x 0.0625 deg. horizontal resolution over the Black Sea. The data are obtained from infra-red measurements collected by satellite radiometers and statistical interpolation. It is the CMEMS sea surface temperature nominal operational product for the Black sea.

This accession contains the daily 25km global Optimally Interpolated Sea Surface Temperature (OISST) in situ and AVHRR analysis, supplemented with AVHRR Pathfinder Version 5.0 climatological SST for inland and coastal pixels, for 1981-09-01 through 2010-12-31. These SST data files were used during the processing of AVHRR Pathfinder Version 5.2 (PFV52) in the following ways:

1. As a first guess SST, used in the calculation of the PFV52 SST value from the brightness temperatures measured by the AVHRR instrument.

2. As a reference SST, against which the final PFV52 SST value is checked. If the difference between these two SST values is too great, the PFV52 SST is assigned a lower quality flag value.

This dataset contains the daily 25km global Optimally Interpolated Sea Surface Temperature (OISST) in situ and AVHRR analysis, supplemented with AVHRR Pathfinder Version 5.0 climatological SST for inland and coastal pixels, for 1981-09-01 through 2010-12-31. These SST data files were used during the processing of AVHRR Pathfinder Version 5.2 (PFV52) in the following ways: As a first guess SST, used in the calculation of the PFV52 SST value from the brightness temperatures measured by the AVHRR instrument. As a reference SST, against which the final PFV52 SST value is checked. If the difference between these two SST values is too great, the PFV52 SST is assigned a lower quality flag value.

This is the final version of the related dataset "ncdcOisst21NrtAgg", which has the preliminary, near real time version of these files. These final files are released about 2 weeks after the NRT files. NOAA/National Centers for Environmental Information (NCEI) 1/4 Degree Daily Optimum Interpolation Sea Surface Temperature (OISST) Analysis, Version 2.1 - Final. NOAAs 1/4-degree Daily Optimum Interpolation Sea Surface Temperature (OISST) (sometimes referred to as Reynolds SST, which however also refers to earlier products at different resolution), currently available as version v02r01, is created by interpolating and extrapolating SST observations from different sources, resulting in a smoothed complete field. The sources of data are satellite (Advanced Very High Resolution Radiometer (AVHRR)) and in situ platforms (i.e., ships and buoys), and the specific datasets employed may change over time. At the marginal ice zone, sea ice concentrations are used to generate proxy SSTs. A preliminary version of this file is produced in near-real time (1-day latency), and then replaced with a final version after 2 weeks. Note that this is the AVHRR-ONLY DOISST, available from Oct 1981, but there is a companion DOISST product that includes microwave satellite data, available from June 2002

Q: What's the temperature of water at the ocean's surface? A: Colors on the map show the temperature of water right at the ocean’s surface. The darkest blue shows the coldest water: floating sea ice is usually present in these areas. Lighter shades of blue show temperatures of up to 80°F. White and orange areas show where surface temperatures are higher than 80°F, warm enough to fuel tropical cyclones or hurricanes. Q: Where do these measurements come from? A: Satellite instruments measure sea surface temperature—often abbreviated as SST—by checking how much energy comes off the ocean at different wavelengths. Computer programs merge sea surface temperatures from ships and buoys with the satellite data, and incorporate information from maps of sea ice. To produce the daily maps, programs invoke mathematical filters to combine and smooth data from all three sources. Q: What do the colors mean? A: The darkest blue areas show sea surface temperatures as low as 28°F. Sea ice, which can look like anything from a slushy mix of floating ice crystals to a solid surface of white, is usually present in these areas. Progressively lighter shades of blue show increasingly warmer temperatures, up to 80°F. White and orange areas on the map show where the surface temperature is above 80°F. Tropical storms that cross these areas can strengthen to form cyclones and hurricanes. Q: Why do these data matter? A: While heat energy is stored and mixed throughout the depth of the ocean, the temperature of water right at the sea's surface—where the ocean is in direct contact with the atmosphere—plays a significant role in weather and short-term climate. Where sea surface temperatures are high, relatively large amounts of heat energy and moisture enter the atmosphere, sometimes producing powerful, drenching storms downwind. Conversely, lower sea surface temperatures mean less evaporation. Global patterns of sea surface temperatures are an important factor for weather forecasts and climate outlooks. Q: How did you produce these snapshots? A: Data Snapshots are derivatives of existing data products: to meet the needs of a broad audience, we present the source data in a simplified visual style. NOAA's Climate Data Records Program produces the Opitimum Interpolated Sea Surface Temperature files. To produce our images, we run a set of scripts that access the source files, re-project them into desired projections at various sizes, and output them with a custom color bar. Additional information Various scientific groups have produced datasets showing Sea Surface Temperature. The images in Data Snapshots represent the AVHRR-only 1/4° daily OISST dataset. Data snapshots presents just one daily OISST image every seven days References Optimum Interpolation Sea Surface Temperature Technical Notes [pdf] Climate Data Record (CDR) Program Climate Algorithm Theoretical Basis Document (C-ATBD) Daily 1/4° Optimum Interpolation Sea Surface Temperature (OISST) Richard W. Reynolds, Thomas M. Smith, Chunying Liu, Dudley B. Chelton, Kenneth S. Casey, and Michael G. Schlax, 2007: Daily High-Resolution-Blended Analyses for Sea Surface Temperature. J. Climate, 20, 5473–5496. doi: http://dx.doi.org/10.1175/2007JCLI1824.1 Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version 2.1 About Optimum Interpolation Sea Surface Temperature (OISST) v2.1 Source: https://www.climate.gov/maps-data/data-snapshots/data-source/sst-sea-surface-temperature This upload includes two additional files:* SST - Sea Surface Temperature _NOAA Climate.gov.pdf is a screenshot of the main Climate.gov site for these snapshots (https://www.climate.gov/maps-data/data-snapshots/data-source/sst-sea-surface-temperature)* Cimate_gov_ Data Snapshots.pdf is a screenshot of the data download page for the full-resolution files.

Daily OISST for paired grids centered on nearshore, backreef, and forereef environments in southern Belize.

Map showing core extraction sites from Castillo et al. (2011)

A Group for High Resolution Sea Surface Temperature (GHRSST) global Level 4 sea surface temperature analysis produced daily on a 0.25 degree grid at the NOAA National Climatic Data Center. This product uses optimal interpolation (OI) using data from the 4 km Advanced Very High Resolution Radiometer (AVHRR) Pathfinder Version 5 time series (when available, otherwise operational NOAA AVHRR data are used) and in situ ship and buoy observations. A second similar product is available that also includes Advanced Microwave Scanning Radiometer-EOS (AMSR-E) data from June 2002 onward. The OI analysis is a daily average SST that is bias adjusted using a spatially smoothed 7-day in situ SST average and is thus tuned to about 0.3 meter. Both day and night satellite fields are independently bias adjusted. More information is available at http://www.ncdc.noaa.gov/oa/climate/research/sst/oi-daily.php

The Sea Surface Temperature - WHOI dataset is part of the NOAA Ocean Surface Bundle (OSB) and provides a high quality Climate Data Record (CDR) of sea surface temperature over ice-free oceans. The SST values are found through modeling the diurnal variability in combination with AVHRR observations of sea surface …

A weekly 1 degree spatial resolution optimum interpolation (OI) sea surface temperature (SST) analysis has been produced at the National Oceanic and Atmospheric Administration (NOAA) using both in situ and satellite data from November 1981 to the present. The weekly product has been available since 1993 and is widely used for weather and climate monitoring and forecasting. Errors in the satellite bias correction and the sea ice to SST conversion algorithm are discussed, and then an improved version of the OI analysis is developed. The changes result in a modest reduction in the satellite bias that leaves small global residual biases of roughly -0.03 degrees Celsius (C). The major improvement in the analysis occurs at high latitudes due to the new sea ice algorithm where local differences between the old and new analysis can exceed 1 C. Comparisons with other SST products are needed to determine the consistency of the OI. These comparisons show that the differences among products occur on large time- and space scales with monthly root mean square differences exceeding 0.5 C in some regions. These regions are primarily the mid- and high-latitude Southern Oceans and the Arctic where data are sparse, as well as high gradient areas such as the Gulf Stream and Kuroshio where the gradients cannot be properly resolved on a 1 degree grid. In addition, globally averaged differences of roughly 0.05 C occur among the products on decadal scales. These differences primarily arise from the same regions where the rms differences are large. However, smaller unexplained differences also occur in other regions of the midlatitude Northern Hemisphere where in situ data should be adequate. Citation: Reynolds, R.W., N.A. Rayner, T.M. Smith, D.C. Stokes, and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609-1625.

OISST-V2-AVHRR-AMSR Daily 1/4 degree Dimensioned By time, depth, latitude, longitude. _CoordSysBuilder=ucar.nc2.dataset.conv.CF1Convention cdm_data_type=Grid Contact=Dick Reynolds, email: Richard.W.Reynolds@noaa.gov & Chunying Liu, email: Chunying.liu@noaa.gov Conventions=CF-1.4 creation_date=2011-10-04 Description=Reynolds, et al.(2007) Daily High-resolution Blended Analyses. Available at https://journals.ametsoc.org/doi/full/10.1175/2007JCLI1824.1 Climatology is based on 1971-2000 OI.v2 SST, Satellite data: AMSR Navy NOAA18 METOP AVHRR, Ice data: NCEP ice Easternmost_Easting=359.875 geospatial_lat_max=89.875 geospatial_lat_min=-89.875 geospatial_lat_resolution=0.25 geospatial_lat_units=degrees_north geospatial_lon_max=359.875 geospatial_lon_min=0.125 geospatial_lon_resolution=0.25 geospatial_lon_units=degrees_east History=Version 2.0 history=FMRC Best Dataset infoUrl=https://www.ncei.noaa.gov/thredds/catalog/ncFC/fc-oisst-daily-avhrr-amsr-dly/catalog.html?dataset=ncFC/fc-oisst-daily-avhrr-amsr-dly/OISST_Daily_AVHRR_AMSR_Feature_Collection_best.ncd institution=NOAA/NCEI location=Proto fmrc:OISST_Daily_AVHRR_AMSR_Feature_Collection Northernmost_Northing=89.875 Source=NOAA/National Climatic Data Center sourceUrl=https://www.ncei.noaa.gov/thredds/dodsC/ncFC/fc-oisst-daily-avhrr-amsr-dly/OISST_Daily_AVHRR_AMSR_Feature_Collection_best.ncd Southernmost_Northing=-89.875 time_coverage_end=2011-10-04T00:00:00Z time_coverage_start=2002-06-01T00:00:00Z Westernmost_Easting=0.125

[There is a newer version of this dataset: ncdcOisst21Agg .] Reynolds, et al.(2007) Daily High-resolution Blended Analyses. This version of the dataset contains the final version of the data. Background information is available at https://www.ncdc.noaa.gov/oisst. Climatology is based on 1971-2000 OI.v2 SST, Satellite data: Navy NOAA17 NOAA18 AVHRR, Ice data: GSFC ice.

The NOAA 0.25° daily Optimum Interpolation Sea Surface Temperature (or daily OISST) is an analysis constructed by combining observations from different platforms (satellites, ships, buoys) on a regular global grid. A spatially complete SST map is produced by interpolating to fill in gaps.

The 1991-2020 climate normals for sea surface temperature (SST) were computed from the NOAA Daily Optimum Interpolation SST (OISST) dataset, in accordance to the climate normals guidelines of the World Meteorological Organization (WMO). The product includes SST mean, standard deviation, count, and extreme parameters. The spatial coverage of the product is on 0.25° spatial grids. This normals dataset is generated based on the 1991-2020 daily OISST with outputs of mean parameters for daily, monthly, seasonal, and annual time scales. The 15-year normals for the period 2006-2020 are also computed as a supplemental product. The data files are in netCDF format.

The NOAA 1/4° Daily Optimum Interpolation Sea Surface Temperature (OISST) is a long term Climate Data Record that incorporates observations from different platforms (satellites, ships, buoys and Argo floats) into a regular global grid. The dataset is interpolated to fill gaps on the grid and create a spatially complete map of sea surface temperature. Satellite and ship observations are referenced to buoys to compensate for platform differences and sensor biases. OISST v2.1 replaced v2 on April 1, 2020. V2 stopped production on April 26, 2020 after its input datasets were discontinued. Data are currently available from September 1, 1981—present, and updated every day. V2.1 has significant quality improvements for data from January 1, 2016 onward.

OISST-V2-AVHRR Daily 1/4 degree Dimensioned By time, depth, latitude, longitude. _CoordSysBuilder=ucar.nc2.dataset.conv.CF1Convention cdm_data_type=Grid comment=Data was converted from NetCDF-3 to NetCDF-4 format with metadata updates in November 2017. Conventions=CF-1.4, ACDD-1.3 Easternmost_Easting=359.875 geospatial_lat_max=89.875 geospatial_lat_min=-89.875 geospatial_lat_resolution=0.25 geospatial_lat_units=degrees_north geospatial_lon_max=359.875 geospatial_lon_min=0.125 geospatial_lon_resolution=0.25 geospatial_lon_units=degrees_east history=Final file created using preliminary as first guess, and 3 days of AVHRR data. Preliminary uses only 1 day of AVHRR data. ; FMRC Best Dataset id=oisst-avhrr-v02r01.20250724.nc infoUrl=https://www.ncei.noaa.gov/thredds/catalog/ncFC/fc-oisst-daily-avhrr-only-dly/catalog.html?dataset=ncFC/fc-oisst-daily-avhrr-only-dly/OISST_Daily_AVHRR-only_Feature_Collection_best.ncd institution=NOAA/NCEI instrument=Earth Remote Sensing Instruments > Passive Remote Sensing > Spectrometers/Radiometers > Imaging Spectrometers/Radiometers > AVHRR > Advanced Very High Resolution Radiometer instrument_vocabulary=Global Change Master Directory (GCMD) Instrument Keywords keywords_vocabulary=Global Change Master Directory (GCMD) Earth Science Keywords location=Proto fmrc:OISST_Daily_AVHRR-only_Feature_Collection metadata_link=https://doi.org/10.25921/RE9P-PT57 naming_authority=gov.noaa.ncei ncei_template_version=NCEI_NetCDF_Grid_Template_v2.0 Northernmost_Northing=89.875 platform=Ships, buoys, Argo floats, MetOp-A, MetOp-B platform_vocabulary=Global Change Master Directory (GCMD) Platform Keywords processing_level=NOAA Level 4 references=Reynolds, et al.(2007) Daily High-Resolution-Blended Analyses for Sea Surface Temperature (available at https://doi.org/10.1175/2007JCLI1824.1). Banzon, et al.(2016) A long-term record of blended satellite and in situ sea-surface temperature for climate monitoring, modeling and environmental studies (available at https://doi.org/10.5194/essd-8-165-2016). Huang et al. (2020) Improvements of the Daily Optimum Interpolation Sea Surface Temperature (DOISST) Version v02r01, submitted.Climatology is based on 1971-2000 OI.v2 SST. Satellite data: Pathfinder AVHRR SST, Navy AVHRR SST, and NOAA ACSPO SST. Ice data: NCEP Ice and GSFC Ice. sensor=Thermometer, AVHRR source=ICOADS, NCEP_GTS, GSFC_ICE, NCEP_ICE, Pathfinder_AVHRR, Navy_AVHRR, NOAA_ACSP sourceUrl=https://www.ncei.noaa.gov/thredds/dodsC/ncFC/fc-oisst-daily-avhrr-only-dly/OISST_Daily_AVHRR-only_Feature_Collection_best.ncd Southernmost_Northing=-89.875 standard_name_vocabulary=CF Standard Name Table (v40, 25 January 2017) time_coverage_end=2025-07-26T12:00:00Z time_coverage_start=2020-02-28T12:00:00Z Westernmost_Easting=0.125

The National Oceanic and Atmospheric Administration (NOAA) / National Environmental Satellite Date and Information Service (NESDIS)/ National Centers for Environmental Information (NCEI) Daily Optimum Interpolation Sea Surface Temperature (SST), version 2.0, dataset (DOISST v2.0) is a blend of in situ ship and buoy SSTs with satellite SSTs derived from the Advanced Very High Resolution Radiometer (AVHRR). DOISST v2.0 exhibited a cold bias in the Indian, South Pacific, and South Atlantic Oceans that is due to a lack of ingested drifting-buoy SSTs in the system, which resulted from a gradual data format change from the traditional alphanumeric codes (TAC) to the binary universal form for the representation of meteorological data (BUFR). The cold bias against Argo was about −0.14 degrees Celcius (°C) on global average and −0.28°C in the Indian Ocean from January 2016 to August 2019. We explored the reasons for these cold biases through six progressive experiments. These experiments showed that the cold biases can be effectively reduced by adjusting ship SSTs with available buoy SSTs, using the latest available International Comprehensive Ocean-Atmosphere Data Set (ICOADS) R3.0.2 derived from merging BUFR and TAC, as well as by including Argo observations above 5-meter (m) depth. The impact of using the Meteorological operational satellite - B (MetOp-B) instead of NOAA-19 was notable for high-latitude oceans but small on global average, since their biases are adjusted using in situ SSTs. In addition, the warm SSTs in the Arctic were improved by applying a freezing point instead of regressed ice-SST proxy. This paper describes an upgraded version, DOISST v2.1, which addresses biases in v2.0. Overall, by updating v2.0 to v2.1, the biases are reduced to −0.07° and −0.14°C in the global ocean and Indian Ocean, respectively, when compared with independent Argo observations and are reduced to −0.04° and −0.08°C in the global ocean and Indian Ocean, respectively, when compared with dependent Argo observations. The difference against the Group for High Resolution SST (GHRSST) Multiproduct Ensemble (GMPE) product is reduced from −0.09° to −0.01°C in the global oceans and from −0.20° to −0.04°C in the Indian Ocean.