ACSPO Global 0.02º Gridded Super-collated SST and Thermal Fronts from Low-Earth-Orbiting Platforms (L3S-LEO)

NOAA Advanced Clear-Sky Processor for Ocean (ACSPO) L3S-LEO SST is a family of multisensor gridded ("L3") 0.02º resolution super-collated ("S") products. The L3S-LEO family is organized into three lines: PM, AM and Daily. The AM and PM lines correspond to 9:30am/pm and 1:30am/pm equator crossing times, respectively. The Daily line combines PM and AM (day and night) SSTs into a single daily L3S SST that is normalized to 1:30am viewing conditions.

    Data Access
    Metadata
    HTTPS
    THREDDS
    ERDDAP
    PO.DAAC Archive
    NCEI Archive
    Sample Filenames

    Near Real-Time (NRT) Operational Production (source: OSPO)

    20240930120000-OSPO-L3S_GHRSST-SSTsubskin-LEO_AM_D-ACSPO_V2.80-v02.0-fv01.0.nc
    20240930120000-OSPO-L3S_GHRSST-SSTsubskin-LEO_AM_N-ACSPO_V2.80-v02.0-fv01.0.nc
    20240930120000-OSPO-L3S_GHRSST-SSTsubskin-LEO_PM_D-ACSPO_V2.80-v02.0-fv01.0.nc
    20240930120000-OSPO-L3S_GHRSST-SSTsubskin-LEO_PM_N-ACSPO_V2.80-v02.0-fv01.0.nc
     

    Research Production (source: STAR)

    20200330120000-STAR-L3S_GHRSST-SSTsubskin-LEO_AM_N-ACSPO_V2.80-v02.0-fv01.0.nc
    20200330120000-STAR-L3S_GHRSST-SSTsubskin-LEO_AM_D-ACSPO_V2.80-v02.0-fv01.0.nc
    20200330120000-STAR-L3S_GHRSST-SSTsubskin-LEO_PM_N-ACSPO_V2.81-v02.0-fv01.0.nc
    20200330120000-STAR-L3S_GHRSST-SSTsubskin-LEO_PM_D-ACSPO_V2.81-v02.0-fv01.0.nc
    20200330120000-STAR-L3S_GHRSST-SSTsubskin-LEO_Daily-ACSPO_V2.81-v02.0-fv01.0.nc

    Global map projection display SST data

    The NOAA Advanced Clear-Sky Processor for Ocean (ACSPO) L3S-LEO is a family of multisensor super-collated (L3S) gridded 0.02º resolution SST products from low earth orbit (LEO) satellites. The L3S-LEO family is organized into three lines: PM, AM and Daily. The AM (mid-morning orbit) and PM (afternoon orbit) lines contain SST data from satellites with 9:30am/pm and 1:30am/pm equator crossing times, respectively. Both AM and PM lines are split into day-time (solar zenith angle < 90º) and night-time (solar zenith angle >= 90º) files, resulting in 4 files per day in total, which approximately cover the 24 hours diurnal cycle in 4 points. The Daily (DY) line combines PM and AM (day and night) SSTs into a single daily L3S SST that is normalized to 1:30am viewing conditions using a statistical model informed by surface wind speed and shortwave radiation.

    The AM product is produced from three (currently two active) AVHRR FRACs (flown aboard METOP-A, B and C). The PM product is produced from three VIIRSs (flown aboard NPP, N20, N21) and MODIS (onboard Aqua; included until Dec 31 2022). The DY product is produced by combining all four L3S-LEO-AM/PM day/night SSTs. SST from Terra MODIS is also included in DY in until 31 Dec 2021.

    All L3S-LEO products contain information about thermal fronts, which is included in ACSPO files in two new variables ‘sst_front_position’ and ‘sst_gradient_magnitude’. The first variable is a binary indicator of SST front position. It is set to ‘1’ where a front is present, and to ‘0’ elsewhere. The second variable is the SST gradient magnitude (in units of K/km).

    L3S-LEO data are provided in GHRSST Data Specification v2 (GDS2) NetCDF format, as L3S (gridded, super-collated, 0.02º). We plan to create an L3S-GEO line, and eventually consolidate the L3S-LEO and L3S-GEO into one sensor-agnostic L3S SST product.

    All ACSPO L3S-LEO products provided here are mature and validated. Please contact the CoastWatch helpdesk with any questions.

    Short Names
    ACSPO-L3S-LEO-PM-v2.81
    ACSPO-L3S-LEO-AM-v2.80
    ACSPO-L3S-LEO-Daily-v2.81
    Temporal Start Date
    February 24, 2000
    Product Families
    Sea Surface Temperature
    Measurements
    Sea Surface Temperature - Polar-orbiting
    Processing Levels
    Level 3
    Latency Groups
    0 Hours <= 24 Hours (NRT)
    Latency Details

    24 hours

    Spatial Resolution Groups
    2km+
    Spatial Resolution Details

    0.02°

    Data Providers
    NOAA
    NESDIS
    STAR
    Spatial Coverage

    Global

    Description

    180W - 180E
    90N - 90S

    ACSPO

    Description

     Advanced Clear Sky Processor for Ocean (ACSPO) is the NOAA Enterprise SST system

    Aqua

    Description

    Earth Observation System - Aqua

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    Orbital Altitude
    705 km
    Equatorial Crossing Times
    13:30 asc

    MetOp

    Description

    Meteorological Operational satellite - A / B / C

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    ESA
    EUMETSAT
    Orbital Altitude
    827 km
    Equatorial Crossing Times
    07:50 desc

    NOAA

    Description

    National Oceanic and Atmospheric Administration - 17 / 18 / 19 / 20 / 21

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    NOAA
    Orbital Altitude
    834 km
    Equatorial Crossing Times
    13:25 asc

    SNPP

    Description

    Suomi National Polar-orbiting Partnership

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    NOAA
    Orbital Altitude
    833 km
    Equatorial Crossing Times
    13:25 asc

    Terra

    Description

    Earth Observation System - Terra

    Platform Type
    Low Earth Orbit Satellite (LEO)
    Instruments
    Organizations
    NASA
    Orbital Altitude
    705 km
    Equatorial Crossing Times
    10:30 desc

    AVHRR

    Description

    Advanced Very High Resolution Radiometer

    Platforms
    Instrument Types
    Imager
    Organizations
    NOAA

    MODIS

    Description

    Moderate-resolution Imaging Spectro-radiometer

    Platforms
    Instrument Types
    Imager
    Organizations
    NASA

    VIIRS

    Description

    Visible Infrared Imaging Radiometer Suite

    Platforms
    Instrument Types
    Imager
    Organizations
    NASA

    Algorithms

    • Jonasson, O.; Gladkova, I.; Ignatov, A. Towards global daily gridded super-collated SST product from low earth orbiting satellites (L3S-LEO-Daily) at NOAA. Proc. SPIE 202212118, 1211805, doi:10.1117/12.2620103, [pdf paper (link)], [mp4 presentation (link)], [ppt presentation (link)].
    • Jonasson, O.; Gladkova, I.; Ignatov, A.; Kihai, Y. Algorithmic Improvements and Consistency Checks of the NOAA Global Gridded Super-Collated SSTs from Low Earth Orbiting Satellites (L3S-LEO). Proc. SPIE 2021117521175202, doi:10.1117/12.2585819,  [pdf paper (link)], [mp4 presentation (link)], [ppt presentation (link)].
    • Jonasson, O.; Gladkova, I.; Ignatov, A.; Kihai, Y. Progress with Development of Global Gridded Super-Collated SST Products from Low Earth Orbiting Satellites (L3S-LEO) at NOAA. Proc. SPIE 202011420, 1142002. doi:10.1117/12.2551819. [pdf paper (link)], [mp4 presentation (link)], [ppt presentation (link)].
    • Gladkova, I.; Ignatov, A.; Pennybacker, M.;  Kihai, Y. Towards High-Resolution Multi-Sensor Gridded ACSPO SST Product: Reducing Residual Cloud Contamination. Proc. SPIE 201911014, 110140L. doi:10.1117/12.2518462, [pdf paper (link)], [ppt presentation (link)].
    • Gladkova, I., A. Ignatov, M. Pennybacker, Y. Kihai, 2019: Towards High-Resolution Multi-Sensor Gridded ACSPO L3S SST Product. GHRSTT XX: Science Team Meeting, June 2019, Frascati, Italy [ppt presentation (link)].

    Monitoring

    • SQUAM: Dash, P., A. Ignatov, Y. Kihai, J. Sapper, 2010: The SST Quality Monitor (SQUAM). JTech, 27, 1899-1917, doi:10.1175/2010JTECHO756.1.
    • iQuam: Xu, F., A. Ignatov, 2014: In situ SST Quality Monitor (iQuam). JTech, 31, 164-180, doi:10.1175/JTECH-D-13-00121.1.
    • ARMS: Ding, Y., A. Ignatov, K. He, I. Gladkova, 2018: ACSPO Regional Monitor for SST (ARMS). GHRSTT XIX: Science Team Meeting, June 2018, Darmstadt, Germany  [ppt presentation 21.5Mb (link)].
    • MICROS: Liang, X., A. Ignatov, 2011: Monitoring of IR Clear-sky Radiances over Oceans for SST (MICROS). JTech, 28, 1228-1242, doi:10.1175/JTECH-D-10-05023.1.

    The ACSPO L3S-LEO SST data are provided by NOAA STAR. We strongly recommend contacting Olafur.Jonasson@noaa.gov or Alex.Ignatov@noaa.gov, before the data are used for any publication or presentation.

    ** When you use our data, please reference the product citation (if available) and acknowledge "NOAA CoastWatch" **