CERES SYN1deg¶

CERES and GEO-Enhanced TOA, Within-Atmosphere and Surface Fluxes, Clouds and Aerosols (SYN1deg) Edition4B

Available

At a glance¶

Note on period: As checked on 2026-10-13, ASDC (CMR) holds hourly, daily and monthly files through July 2026. March 2000–June 2002 is Terra only, July 2002–March 2022 Terra plus Aqua, and April 2022 onward NOAA-20 only. The Aqua gap of 16–31 August 2020 was filled with NOAA-20 data; 1–3 September 2020 could not be filled.

Overview¶

CERES broadband radiometer observations combined with hourly information from geostationary (GEO) imagers to fill top-of-atmosphere (TOA) fluxes on an hourly, 1° grid. Coincident MODIS, VIIRS and GEO cloud properties, MATCH aerosols and reanalysis temperature and humidity are fed into the Langley Fu-Liou radiative transfer model to compute shortwave and longwave fluxes at the surface and at levels within the atmosphere, which are included alongside. EBAF is the standard for the monthly energy budget; SYN1deg is the choice when time resolution matters — diurnal cycles, day-to-day variability, extreme events — and for validating surface fluxes.

What changes with the successor¶

SYN1deg Edition4A (Terra+Aqua) → SYN1deg Edition4B (Terra+Aqua+NOAA-20)¶

Transition: 2025-05

A revised edition that switches April 2022 onward to NOAA-20 alone with MERRA-2 inputs, and fixes early geostationary cloud retrievals and twilight handling. The DQS states that Ed4A will not be reprocessed until Edition 5 is available, so Ed4B is the record that continues today.

Sources: CERES SYN1deg Ed4A/Ed4B Data Quality Summary (V1, 2025-05-08) · NASA CMR — CER_SYN1deg-1Hour_Terra-Aqua-NOAA20 Edition4B

Available variables¶

Names are the HDF SDS names in the Ed4A Data Products Catalog (SYN1deg-1Hour R6V1). Names in Ed4B files and in netCDF orders from the CERES ordering tool may differ, so check them in your files. Cloud variables carry a five-layer dimension (high, upper-mid, lower-mid, low, total).

instantaneous mean accumulated maximum minimum static — instantaneous: value at the time stamp · mean/accumulated/maximum/minimum: over the indicated interval · static: does not change with time

Observed TOA fluxes (CERES + GEO)¶

Computed surface fluxes (Fu-Liou, initial)¶

Cloud properties (MODIS, VIIRS, GEO)¶

Aerosol¶

The full variable list is in the official documentation.

How to get the data¶

• CERES ordering and subsetting tool (SYN1deg Ed4.2 = Edition4B) — Web order (choose variables, period and region → NetCDF3, up to 2 GB)
  • Choose monthly, monthly-hourly, daily or hourly, and regional (1°), zonal or global means. Selecting only the variables you need makes this the easiest route for hourly data.
• NASA Earthdata Search — CER_SYN1deg-1Hour_Terra-Aqua-NOAA20 Edition4B — Earthdata Search / earthaccess (HDF4, one file per day)
  • The daily product is CER_SYN1deg-Day, monthly CER_SYN1deg-Month and monthly-hourly CER_SYN1deg-MHour (all _Terra-Aqua-NOAA20, Edition4B). A free NASA Earthdata login is required.
• CERES data page (SYN1deg product table and availability) — Web

Example code¶

Run earthaccess.login() once with a NASA Earthdata account. ASDC files are HDF4, so read them with pyhdf and list the variable names with f.datasets() first.

# pip install earthaccess pyhdf numpy
import earthaccess
from pyhdf.SD import SD, SDC

earthaccess.login()
results = earthaccess.search_data(
    short_name="CER_SYN1deg-1Hour_Terra-Aqua-NOAA20",
    version="Edition4B",
    temporal=("2025-07-01", "2025-07-01"),
)
files = earthaccess.download(results[:1], "./syn1deg")   # one day of hourly data

f = SD(files[0], SDC.READ)
print(sorted(f.datasets().keys())[:20])                 # list variable (SDS) names
olr = f.select("obs_all_toa_lw")[:]                     # expected (24 hours, 180 lat, 360 lon)
print(olr.shape)

Practical tips¶

• For long-term changes in monthly TOA and surface fluxes use EBAF, not SYN1deg. The SYN1deg Ed4A DQS states that the product is not of climate quality and should not be used to infer long-term trends in clouds or fluxes.
• The DQS advises against the adjusted (adj_) shortwave and longwave fluxes because of code bugs. Use the initial (init_) surface fluxes, or EBAF-Surface if monthly means are all you need.
• Step changes in fluxes and clouds can appear when geostationary satellites are replaced (for example GOES, Meteosat or Himawari generation changes). Check for them in regional analyses inside the GEO domain (60°S–60°N).
• In Ed4A the global net TOA imbalance is about +4.5 W m-2, far above the ocean-heating estimate of about 0.7 W m-2. Use EBAF for the absolute energy budget.
• The DQS reports a total solar irradiance scaling error that makes the August 2019 and May–July 2020 monthly values about 0.2 W m-2 too large.
• One day of hourly data is a single file of several hundred MB. Ordering only the variables and region you need through the CERES tool is much lighter.
• Clear-sky values are filled with defaults where no clear-sky footprint exists, so clear-sky zonal means in very cloudy latitude bands may be unrepresentative.

Notices and change history¶

References for your paper¶

Dataset citation¶

SYN1deg-1Hour Edition4B — DOI 10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEG-1HOUR_L3.004B

@misc{ceres_syn1deg_1hour_ed4b,
  author    = {Doelling, David},
  title     = {{CERES} and {GEO}-Enhanced {TOA}, Within-Atmosphere and Surface Fluxes, Clouds and Aerosols 1-Hourly {Terra-Aqua-NOAA20} {Edition4B}},
  year      = {2026},
  publisher = {NASA Langley Atmospheric Science Data Center Distributed Active Archive Center},
  doi       = {10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEG-1HOUR_L3.004B},
  note      = {Accessed DD MMM YYYY}
}

SYN1deg-Day Edition4B — DOI 10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEGDAY_L3.004B

@misc{ceres_syn1deg_day_ed4b,
  author    = {Doelling, David},
  title     = {{CERES} and {GEO}-Enhanced {TOA}, Within-Atmosphere and Surface Fluxes, Clouds and Aerosols Daily {Terra-Aqua-NOAA20} {Edition4B}},
  year      = {2026},
  publisher = {NASA Langley Atmospheric Science Data Center Distributed Active Archive Center},
  doi       = {10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEGDAY_L3.004B},
  note      = {Accessed DD MMM YYYY}
}

SYN1deg-Month Edition4B — DOI 10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEGMONTH_L3.004B

@misc{ceres_syn1deg_month_ed4b,
  author    = {Doelling, David},
  title     = {{CERES} and {GEO}-Enhanced {TOA}, Within-Atmosphere and Surface Fluxes, Clouds and Aerosols Monthly {Terra-Aqua-NOAA20} {Edition4B}},
  year      = {2026},
  publisher = {NASA Langley Atmospheric Science Data Center Distributed Active Archive Center},
  doi       = {10.5067/TERRA-AQUA-NOAA20/CERES/SYN1DEGMONTH_L3.004B},
  note      = {Accessed DD MMM YYYY}
}

Reference papers¶

GEO-enhanced temporal interpolation (TOA) — DOI 10.1175/JTECH-D-12-00136.1

@article{doelling2013geo,
  author  = {Doelling, David R. and Loeb, Norman G. and Keyes, Dennis F. and Nordeen, Michele L. and Morstad, Daniel and Nguyen, Cathy and Wielicki, Bruce A. and Young, David F. and Sun, Moguo},
  title   = {Geostationary Enhanced Temporal Interpolation for {CERES} Flux Products},
  journal = {Journal of Atmospheric and Oceanic Technology},
  volume  = {30},
  number  = {6},
  pages   = {1072--1090},
  year    = {2013},
  doi     = {10.1175/JTECH-D-12-00136.1}
}

Surface flux methodology and validation — DOI 10.1175/JTECH-D-14-00165.1

@article{rutan2015syn,
  author  = {Rutan, David A. and Kato, Seiji and Doelling, David R. and Rose, Fred G. and Nguyen, Le Trang and Caldwell, Thomas E. and Loeb, Norman G.},
  title   = {{CERES} Synoptic Product: Methodology and Validation of Surface Radiant Flux},
  journal = {Journal of Atmospheric and Oceanic Technology},
  volume  = {32},
  number  = {6},
  pages   = {1121--1143},
  year    = {2015},
  doi     = {10.1175/JTECH-D-14-00165.1}
}

CERES mission (reference requested in the DQS) — DOI 10.1175/1520-0477(1996)077<0853:CATERE>2.0.CO;2

@article{wielicki1996ceres,
  author  = {Wielicki, Bruce A. and Barkstrom, Bruce R. and Harrison, Edwin F. and Lee, Robert B. and Smith, G. Louis and Cooper, John E.},
  title   = {Clouds and the Earth's Radiant Energy System ({CERES}): An Earth Observing System Experiment},
  journal = {Bulletin of the American Meteorological Society},
  volume  = {77},
  number  = {5},
  pages   = {853--868},
  year    = {1996},
  doi     = {10.1175/1520-0477(1996)077<0853:CATERE>2.0.CO;2}
}

Acknowledgements¶

The CERES team asks that publications name the product and edition (for example 'CERES SYN1deg-1Hour Edition4B') and cite Wielicki et al. (1996). For data obtained from ASDC, the suggested wording is "These data were obtained from the NASA Langley Research Center Atmospheric Science Data Center."

Information on the datasets used in this study was compiled with the help of the Korean Climate Data Navigator (KCDN) (Sim, 2026; https://doi.org/10.5281/zenodo.23300923).

Links¶

• CERES data page (SYN1deg product table)
• CERES SYN1deg Data Quality Summary (DQS, Ed4A/Ed4B V1)
• SYN1deg-1Hour Data Products Catalog (variable tables)
• CERES documentation index (DQS, DPC)