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CM SAF products describe important components of the Earth´s Energy budget and its water cycle, i.e. water vapour, clouds and their properties, precipitation and surface radiation components. The products include pixel based retrievals of geophysical variables along with daily and monthly aggregations, which enable a large variety of applications wrt. climate analysis and monitoring. More : Our Products


Highlights Archiv

Updated CM SAF Surface Solar Radiation Climate Data Record available

The CM SAF is happy to announce the release of the second edition of the
Surface Radiation Data Set - Heliosat (SARAH-2):

SARAH-2 provides high-quality satellite-based information on surface solar
radiation parameters from 1983 to 2015 covering Europe, Africa, parts of
South America as well as the surrounding ocean areas. The spatial
resolution of 0.05° x 0.05° almost matches the spatial resolution of the
MVIRI and SEVIRI sensors onboard the Meteosat satellites, which have
been used to generate the SARAH-2 data records.

Six surface solar radiation parameters are provided as part of SARAH-2:
the global radiation (SIS, also known as the surface irradiance), the direct
radiation (SID), the direct normalized radiation (DNI, i.e., the radiation
through a horizontal plate perpendicular to the sun), the sunshine
duration (SDU), the spectrally-resolved surface irradiance (SRI), and the
effective cloud albedo (CAL). The sunshine duration and the spectrally-
resolved surface irradiance are newly provided parameters as part of the
second edition of SARAH.

SARAH-2_SIS_mean_Global SARAH-2_SIS_mean_GlobalSurface Solar Radiation, SARAH-2 1983-2015 Source: CM SAF

All data records are available as monthly mean products (monthly sum in the case of SDU) and all except the SRI data record
are also available as daily mean products (daily sum in the case of SDU). For the SIS, SID, DNI, and CAL data records also
instantaneous information is provided every 30 min. These highly temporal resolved data replace the hourly mean data
provided in the first edition of the SARAH data record; this instantaneous information allows a better referencing of the data
to the corresponding solar geometry, which is required for the calculation of the solar radiation on tilted surfaces, e.g., solar

So far, more than 60 peer-reviewed journal articles document the CM SAF Surface Solar Radiation Climate Data Records and
their various fields of applications. These areas of application include (among others) climate monitoring and the assessment
of trends and variability, the validation of climate models, the quality control of surface measurements, the estimation of the
photovoltaic energy potential and its temporal variability and trend, and the use as input parameters for agro- and
hydrometeorological models. Some of these applications can be found in the Outreach-Section of the CM SAF Webpage.
The release of the second edition of the SARAH data record will further enhance the application of the CM SAF surface solar
radiation data records.

JT / June2017

New Climate Data Record available: CLARA-A2 CM SAF Cloud, Albedo, Radiation data record, AVHRR-based, Edition 2

CLARA-2Climatological mean field of CLARA-A2 cloud fractional coverage for the years 1982 – 2015 Source: CM SAF

The CLARA-A2 (CM SAF cLoud, Albedo and surface RAdiation dataset from AVHRR data - Edition 2) record provides cloud
properties, surface albedo and surface radiation parameters derived from the AVHRR sensor onboard polar orbiting NOAA
and METOP satellites. This second edition is the improved and extended follow-up of the first version of the record
(CLARA-A1) which now covers a 34 year time period (1982-2015). CLARA-A2 features a range of cloud products: cloud
mask, cloud top temperature/pressure/height (CTT/CTP/CTH), cloud thermodynamic phase (CPH), cloud optical thickness
(COT), cloud particle effective radius (REF) and cloud water path (CWP). Cloud products are available as monthly and
daily averages and also as daily resampled global products (Level 2b) for individual satellites. Cloud parameter results are
also presented as single-parameter distributions (frequency histograms of CTP, CTT, COT, REF and CWP) and multi-
parameter distributions (joint frequency histograms of COT, CTP and CPH for daytime conditions). Surface albedo is
presented as monthly and pentad (5 day) averages and is derived using all available data during the studied period. Surface
radiation products are provided as monthly averages for the downwelling shortwave (including also daily averages) and the
down- and upwelling longwave components. All monthly and daily averages are available on a 0.25°x0.25° global grid.
Surface albedo and cloud products are also provided in two equal area grids with a resolution of 25 km x 25 km covering
the polar regions. Daily resampled cloud products (level 2b) are provided in a global grid with a resolution of 0.05°x0.05°.
For the latter, also a probabilistic cloud mask is added as an experimental product.
The data record can be ordered via the Web User Interface.

More information on the data record is available from the DOI page:


CLARA-2 TabSource: CM SAF

Technical specifications

Time period1982 – 2015
Temporal resolutiondaily mean, pentad mean, monthly mean, monthly histograms (depending on product) +
daily subsampled global cloud products
Spatial coverageglobal on a regular latitude/longitude grid (polar areas: equal area)
Spatial resolution0.25° x 0.25° for monthly and daily means, 1°x1° for JCH, 0.05° x 0.05° for daily
subsampled products and 25 km x 25 km for polar areas
Data FormatNetCDF 4, Climate and Forecast (CF) Metadata Convention v1.6

Karlsson, K.-G., Anttila, K., Trentmann, J., Stengel, M., Meirink, J. F., Devasthale, A., Hanschmann, T., Kothe, S., Jääskeläinen,
E., Sedlar, J., Benas, N., van Zadelhoff, G.-J., Schlundt, C., Stein, D., Finkensieper, S., Håkansson, N., and Hollmann, R.:
CLARA-A2: The second edition of the CM SAF cloud and radiation data record from 34 years of global AVHRR data, Atmos.
Chem. Phys. Discuss.,, in review, 2017.

Cloud properties - Product User Manual (PUM)
Cloud properties - Validation Report (VAL)
Cloud properties - Algorithm Theoretical Basis Document (ATBD)
Surface Albedo - Product User Manual (PUM)
Surface Albedo - Validation Report (VAL)
Surface Albedo - Algorithm Theoretical Basis Document (ATBD)
Surface radiation - Product User Manual (PUM)
Surface radiation - Validation Report (VAL)
Surface radiation - Algorithm Theoretical Basis Document (ATBD)

MSt / March2017

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