Outgoing longwave radiation

OLR

Net total thermal radiation emitted by the Earth, as measured at the top of atmosphere.

Reflected solar flux

RSF

Net total outgoing shortwave (UV, visible, near-IR) radiation at the top of atmosphere. This is dominated by reflected and scattered solar radiation.

Level-1b

The full-resolution geolocated radiometric measurements (for each view and each channel), rebinned onto a regular spatial grid.

Level-2 (L2)

Retrieved cloud variables at full input data resolution, thus with the same resolution and location as the sensor measurements (Level-1b).

Level-3C (L3C)

Cloud properties of Level-2 orbits of one single sensor combined (averaged) on a global spatial grid. Both daily and monthly products provided through C3S are Level-3C.

Brokered product

The C3S Climate Data Store (CDS) provides both data produced specifically for C3S and so-called brokered products. The latter are existing products produced under an independent programme or project which are made available through the CDS.

Climate Data Store (CDS)

The front-end and delivery mechanism for data made available through C3S.

Near-real-time (NRT)

Data which is provided within a short time window (often taken to be three hours, but there is no fixed definition) of the measurement. NRT data is often supplanted by a subsequent data stream, which is subjected to more rigorous checking data quality.

BUGSrad

The broad-band radiative transfer software used to generate the radiative flux values that make up the SRB CDR.

Radiative transfer

The mathematical modelling of the interaction of electromagnetic radiation with some medium – in this case solar and thermal-infrared radiation passing through the Earth’s atmosphere.

Retrieval

A numerical data analysis scheme which uses some form of mathematical inversion to derive physical properties from some form of measurement. In this case, the derivation of cloud properties from satellite measured radiances.

Forward model

A deterministic model which predicts the measurements made of a system, given its physical properties. The forward model is the function which is mathematically inverted by a retrieval scheme. In this case, the forward model predicts the radiances measured by a satellite instrument as a function of atmospheric and surface state, and cloud properties.

TCDR

It is a consistently-processed time series of a geophysical variable of sufficient length and quality.

ICDR

An Interim Climate Data Record (ICDR) denotes an extension of TCDR, processed with a processing system as consistent as possible to the generation of TCDR.

CDR

A Climate Data Record (CDR) is defined as a time series of measurements with sufficient length, consistency, and continuity to determine climate variability and change.

Swath

Nadir view

512 km

Oblique view

512 km

Global Coverage Revisit Times

3-4 day (mean)

Spatial Sampling interval at Sub-satellite point (km)

VIS-SWIR

1 km

IR

1 km

Spectral channel centre (µm)

VIS

0.554 (Ch1); 0.659 (Ch2) 0.865 (Ch3)

SWIR

1.61 (Ch4)

MWIR/TIR

3.70 (Ch5); 10.85 (Ch6); 12.00 (Ch7)

ERS-2

780

98.5°

100

35

10:30

ENVISAT

799.8

98.55°

100.59

35

10:00

Sentinel-3

814.5

98.65°

100.99

27

±1 km

10:00

Swath

Nadir view

1,400 km

Oblique view

740 km

Global Coverage Revisit Times

(nadir view)

1 satellite

1 day (mean)

2 satellites

0.5 day (mean)

Spatial Sampling interval at Sub-satellite point (km)

VIS-SWIR

0.5 km

IR-Fire

1 km

Spectral channel centre (µm)

VIS

0.554 (S1); 0.659 (S2) 0.868 (S3)

SWIR

1.374 (S4); 1.613 (S5); 2.25 (S6)

MWIR/TIR

3.742 (S7); 10.85 (S8); 12.02 (S9)

Fire ½

3.742 (F1); 10.85 (F2)

Radiometric Resolution

VIS (Albedo =0.5%)

Signal-to-Noise Ratio (SNR) > 20

SWIR (Albedo =0.5%)

Signal-to-Noise Ratio (SNR) > 20

MWIR (T =270K)

NEΔT < 80 mK

TIR (T=270K)

NEΔT < 50 mK

Fire 1 (<500 K)

NEΔT < 1 K

Fire 2 (<400 K)

NEΔT < 0.5 K

Radiometric Accuracy

VIS-SWIR (Albedo = 2-100%)

< 2% (Beginning of Life)

<5% (End of Life)

MWIR –TIR
(265 – 310 K)

< 0.2 K (0.1 K goal)

Fire (< 500 K)

< 3 K

2

S2

0.67 µm

3

S3

0.87 µm

4

S5

1.6 µm

6

S8

10.8 µm

7

S9

12.0 µm

ECMWF ERA-Interim

ECMWF reanalysis products provide pressure, temperature, humidity and ozone profiles, as well a priori surface temperature, sea ice extent and near-surface wind speed for ocean surface reflectance calculation.

MODIS MCD43A1² V006

The MODIS BRDF product provides land-surface reflectance.

IREMIS UW Baseline Fit

The Global Infrared Land Surface Emissivity (IREMIS) University of Wisconsin-Madison Baseline Fit to the MODIS MOD11 emissivity product provides land-surface emissivity.

RTTOV

The standard coefficient and database files provided with RTTOV v 12.1 are used, where not superseded by other auxiliary data (as is the case with the emissivity and surface reflectance atlases)

SOHO and SORCE

Up until September 2019, information on incoming total solar irradiance is supplied by the Solar and Heliospheric Observatory (SOHO) and sOlar Radiation and Climate Experiment (SORCE) satellite records.

NOAA daily TSI CDR and TSIS

From September 2019 on, information on incoming total solar irradiance is supplied by the Total Solar Irradiance CDR produced by NOAA, with measurements from the Total and Spectral Solar Irradiance Sensor (TSIS) on the International Space Station being used for dates too recent to be covered by the NOAA CDR.

Total solar irradiance (TSI)

SOHO and SORCE, or

NOAA daily TSI CDR and TSIS

Solar zenith angle

ORAC output (from L1 data)

Direct and diffuse albedo of the surface (visible and near-IR)

Pre-processor output

Surface temperature

Pre-processor output (ERA5)

Cloud type (clear-sky, liquid water cloud or ice cloud)

ORAC output

Cloud-top height

ORAC output

Cloud optical depth (at 550 nm)

ORAC output

Cloud effective radius

ORAC output

Profiles of temperature, pressure, humidity and ozone-concentration, as a function of height.

Pre-processor output (ERA5)

Aerosol optical depth (optional)

Aerosol_cci L2, C3S aerosol L2 or MODIS L2.

Latitude

Degrees North

lat

Values correspond to grid centres (-89.75°, -89.25°, -88.75°, …, 89.75°)

Longitude

Degrees East

lon

Values correspond to grid centres (-179.75°, -179.25°, -178.75°, …, 179.75°)

Pixel count

-

pixel_count

The total number of level 2 pixels included in the averaging (both cloudy and clear).

Cloud pixel count

-

cloud_count

The number of level 2 cloud pixels included in the averaging (NB. Does not include number of Aerosol_cci pixels included).

Top-of-atmosphere reflected solar flux

Wm^-2

rsf

Top-of-atmosphere outgoing longwave radiation

Wm^-2

olr

title

Descriptive title of the file contents

project

“Climate Change Initiative-European Space Agency”

product_version

The version number of the product

conventions

Lists the naming and meta data conventions used

standard_name_vocabulary

Defines the standard name convention used

institution

The source institution of the data

source

The source (level 1) data used in the product

geospatial_lon_resolution

The grid spacing in the longitude axis

geospatial_lat_resolution

The grid spacing in the latitude axis

geospatial_lon_min

The minimum longitude covered by the product

geospatial_lon_max

The maximum longitude covered by the product

geospatial_lat_min

The minimum latitude covered by the product

geospatial_lat_max

The maximum latitude covered by the product

spatial_resolution

Alternative description of the spatial grid used.

geospatial_vertical_min

Definition of vertical grid used (0 indicated no vertical grid)

geospatial_vertical_max

Definition of vertical grid used (0 indicated no vertical grid)

platform

Satellite platform from which observations originated

sensor

Satellite sensor which made the observations used

creator_email

contact.cloudcci@dwd.de

creator_url

www.esa-cloud-cci.org

date_created

ISO date and time string of processing time of the particular file

creator_name

Alternative for institution

time_coverage_duration

ISO time string defining temporal coverage of the product

time_coverage_resolution

ISO time string defining temporal resolution of the product

references

Link to further information about the product

history

Brief description of provenance of the product

summary

Brief description of product contents

keywords

List of keywords (for data discovery)

comment

Any further comments on the product not covered by other fields

license

License conditions of the product

cdm_data_type

Common Data Model Data Type used in the NetCDF file

keywords_vocabulary

The standard list from which the keywords have been extracted

naming_authority

ID string of the institution naming product (and contents)

tracking_id

An ISO Universally Unique Identifier (UUID) number for the file

id

A human readable identifier of the product

time_coverage_start

ISO time string of the start of the product’s temporal coverage

time_coverage_end

ISO time string of the end of the product’s temporal coverage

inputfilelist

List of the primary input files used to create the product