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Accessing CM SAF data

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Highlights


Highlights Archiv

Release of a first aerosol product in CM SAF

The CM SAF is happy to announce the release its Climate Data Record of Aerosol Optical Depth (AOD) derived from the
Spinning Enhance Visible and InfraRed Imager (SEVIRI) sensors onboard the Meteosat Second Generation (MSG)
satellites. This record covers the period from 1 Feb 2004 to 31 Dec 2012 (Meteosat-8 and -9) and consists of daily and
monthly means of AOD.

Aerosols have many impacts on the climate on our planet: direct through the scattering and absorption of radiation, and
also indirectly through the cloud nucleation and precipitation processes. Concerning the direct effect, the most relevant
parameters are the AOD and, to a lesser extent, the single scattering albedo. In the frame of climate monitoring, the
continuous monitoring of those parameters is of prime importance to understand climate variability and change.
Monitoring aerosols is also important as they have in general an adverse effect on the retrieval of many geophysical
parameters relevant for climate as, for instance, the surface albedo.

The Land Daily Aerosol (LDA) algorithm, developed at EUMETSAT, is used to process this CDR of AOD. The
algorithm performs, on a daily basis and at full pixel scale, the inversion of the accumulated solar band observations
(0.6µm, 0.8µm and 1.6µm) to estimate simultaneously the AOD (a single value at reference wavelength of 550nm) and
the 4 Rahman-Pinty-Verstraete (RPV) parameters of the surface in the 3 bands. The algorithm performs therefore an
optimization on 13 unknowns (the AOD + 3 x 4 RPV parameters). In addition, the optimization is also done over a set of
different models of aerosol microphysics (single scattering albedo, phase function).

An example of monthly mean AOD product is shown in Figure 1

Monthly mean of AOD for June 2004 Monthly mean of AOD for June 2004Monthly mean of AOD for June 2004 Source: CM SAF

Along with the data and the uncertainty estimates, a comprehensive documentation including product user manual,
algorithm descriptions, and validation report is provided. The documents and the data record can be accessed from the
DOI landing page: https://doi.org/10.5676/EUM_SAF_CM/MSG_AOD/V001

References:
- Govaerts, Y. M., Wagner, S., Lattanzio, A., & Watts, P. (2010). Joint retrieval of surface reflectance and aerosol
optical depth from MSG/SEVIRI observations with an optimal estimation approach: 1. Theory. Journal of Geophysical
Research: Atmospheres, 115(D2).
- Wagner, S. C., Govaerts, Y. M., & Lattanzio, A. (2010). Joint retrieval of surface reflectance and aerosol optical
depth from MSG/SEVIRI observations with an optimal estimation approach: 2. Implementation and evaluation. Journal
of Geophysical Research: Atmospheres, 115(D2).
NC / Dec 2017


Release of the HOAPS 4 data record

The Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite data record (HOAPS) is a completely satellite based
climatology of various flux and atmospheric parameters over the global ice free oceans. A new version (HOAPS 4) has
recently been released by CM SAF. All HOAPS variables are derived from recalibrated and intercalibrated measurements
from SSM/I and SSMIS passive microwave radiometers (Fennig et al., 2017), except for the SST, which is taken from
AVHRR measurements (Reynolds et al, 2007). The data record includes multi-satellite averages and an efficient sea ice
detection procedure. Main changes in this version are a prolonged time series, now containing data for the time period
from July 1987 until December 2014, the utilisation of an updated SSM/I and SSMIS FCDR from CM SAF, the provision
of uncertainty estimates for latent heat flux,evaporation, near surface specific humidity and near surface wind speed (Kinzel
et al., 2017) and the implementation of a 1D-Var retrieval scheme for the retrieval of total column water vapour and near
surface wind speed. Other retrieval algorithms remain unchanged compared to HOAPS 3.2 (Andersson et al., 2010). All
HOAPS products have global coverage, i.e., within ±180° longitude and ±80° latitude and are only defined over the ice-free
ocean surface. The products are available as monthly averages and 6-hourly composites on a regular latitude/longitude grid
with a spatial resolution of 0.5° x 0.5° degrees. Climatological maps are exemplarily shown in Figure 1.

HOAPS 4.0 HOAPS 4.0Figure 1 Source: CM SAF


Climatological maps of evaporation (top left),
precipitation (top right) and freshwater flux (bottom).


The maps show averages over the period 1988-2014.

HOAPS was originally developed at the Max-Planck-Institute for Meteorology (MPI-M) and the University of Hamburg (UHH),
with a first release of the HOAPS 1 in 1998. HOAPS has been successfully transferred into the operational environment at
CM SAF. With the release of HOAPS 3.1 in 2009 the processing is carried out at CM SAF while scientific improvements are
developed jointly at MPI-M, UHH and CM SAF. A subset of the HOAPS parameters is released by CM SAF
via http://www.cmsaf.eu/wui. These parameters include:
• precipitation, evaporation, freshwater budget (evaporation minus precipitation), latent heat flux,
• total column water vapour, near surface specific humidity and near surface wind speed.

Along with the data and the uncertainty estimates, a comprehensive documentation including user manual, algorithm
descriptions, reprocessing layout and extensive validation studies, are provided. The documents and the data record can
be accessed from the DOI landing page https://doi.org/10.5676/EUM_SAF_CM/HOAPS/V002.

The following parameters are accessible following the instructions given at
http://www.hoaps.org/index.php?id=data_access:
• Vertically integrated total (liquid and ice) water, surface net longwave radiation, sea surface temperature, sea surface
saturation specific humidity, difference in humidity, latent heat transfer coefficient, sensible heat flux.

Additional information on HOAPS is also available at http://www.hoaps.org.

References:
Andersson, A., Fennig, K., Klepp, C., Bakan, S., Grassl, H., and Schulz, J.: The Hamburg Ocean Atmosphere Parameters
and Fluxes from Satellite Data - HOAPS-3, Earth System Science Data, 2, 215–234, DOI:10.5194/essd-2-215-2010, 2010.
Fennig, Karsten; Schröder, Marc; Hollmann, Rainer : Fundamental Climate Data Record of Microwave Imager Radiances,
Edition 3. Satellite Application Facility on Climate Monitoring. DOI:10.5676/EUM_SAF_CM/FCDR_MWI/V003, 2017.
Kinzel, J., M. Schröder, K. Fennig, A. Andersson, R. Hollmann: Uncertainty characterization of HOAPS-3.3 latent heat
flux related parameters. Atmos. Meas. Tech. Discuss., DOI:10.5194/amt-2017-176, in review, 2017.
Reynolds, R. W., Smith, T. M., Liu, C., Chelton, D. B., Casey, K., and Schlax, M. G.: Daily High-Resolution-Blended
Analyses for Sea Surface Temperature, J. Climate, 20, 5473–5496, DOI:10.1175/2007JCLI1824.1, 2007.
MS / Oct 2017


Updated CM SAF Top-Of-Atmosphere Radiation GERB/SEVIRI Climate Data Record available

The CM SAF is happy to announce the release of the second edition of the
TOA Radiation GERB/SEVIRI Data Record:
http://doi.org/10.5676/EUM_SAF_CM/TOA_GERB/V002

The data record provides estimates of the Top-Of-Atmosphere broadband
radiative fluxes derived from the Geostationary Earth Radiation Budget
(GERB) and the Spinning Enhance Visible and InfraRed Imager
(SEVIRI) sensors onboard the Meteosat Second Generation satellites.
The fluxes are reported as TOA Reflected Solar (TRS aka shortwave
flux) and TOA Emitted Thermal (TET aka longwave flux or outgoing
longwave radiation). In addition to the all-sky fluxes, their clear-sky
counterparts are also provided, allowing for instance the estimation of
the cloud radiative effect or a better evaluation of the radiative schemes
in climate/NWP models. The TOA incoming flux is also provided and can
be used to estimate the “net” radiation budget.

TOA Reflected Solar fluxes TOA Reflected Solar fluxesIllustration 1: daily mean TOA Reflected Solar fluxes in all-sky (left) and clear sky Source: CM SAF

The original GERB level 2.0 High Resolution (HR) and SEVIRI level 1.5 observations have been processed to estimate solar
and thermal fluxes in hourly boxes on the GERB HR grid. From the hourly values, the daily mean, the monthly mean and the
monthly mean diurnal cycle are estimated. Finally, the data is regridded on a regular latitude-longitude grid covering 70°N-70°
and 70°W-70°E, with a spatial resolution of 0.1°.

Being based on 15' geostationary observations, the data record is very well suited to study the diurnal cycle of atmospheric
radiation, e.g. the effect of convection on the OLR. The spatial resolution of the data, 0.1°, allows to study the effect on
the radiation budget of processes taking place at fine spatial scale, e.g. valley fog. Combining the all-sky and clear-sky allows
quantifying the cloud radiative effects at high spatial and temporal resolution.

A special effort has been put on the estimation of the accuracies of the fluxes which are reported at the pixel level in the daily
and monthly mean products.

The data record can be ordered via the Web User Interface.

Technical specifications

Time period
1st Feb. 2004 to 30th April 2015
Temporal resolutiondaily mean, monthly mean, monthly mean of hourly means.
Spatial coverage and resolution70°N-70°S and 70°W-70°E on a regular latitude-longitude grid at 0.1° resolution
SensorsSEVIRI on MSG1,2,3, GERB on MSG1,2
Ancillary inputsERA-interim, CM SAF CLAAS-2 cloud mask
Data Format NetCDF 4, Climate and Forecast (CF) Metadata Convention v1.6

NC / Sept2017

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