The Role of the Effective Cloud Albedo for Climate Monitoring and Analysis

Cloud properties and the Earth’s radiation budget are defined as essential climate variables by the Global Climate Observing System (GCOS). The cloud albedo is a measure for the portion of solar radiation reflected back to space by clouds. This information is essential for the analysis and interpretation of the Earth’s radiation budget and the solar surface irradiance. We present and discuss a method for the production of the effective cloud albedo and the solar surface irradiance based on the visible channel (0.45–1 μm) on-board of the Meteosat satellites. This method includes a newly developed self-calibration approach and has been used to generate a 23-year long (1983–2005) continuous and validated climate data record of the effective cloud albedo and the solar surface irradiance. Using this climate data record we demonstrate the ability of the method to generate the two essential climate variables in high accuracy and homogeneity. Further on, we discuss the role of the cloud albedo within climate monitoring and analysis. We found trends with opposite sign in the observed effective cloud albedo resulting in positive trends in the solar surface irradiance over ocean and partly negative trends over land. Ground measurements are scarce over the ocean and thus satellite-derived effective cloud albedo and solar surface irradiance constitutes a unique observational data source. Within this scope it has to be considered that the ocean is the main energy reservoir of the Earth, which emphasises the role of satellite-observed effective cloud albedo and derived solar surface irradiance as essential climate variables for climate monitoring and analysis.

[1]  R. Hollmann,et al.  The CM-SAF operational scheme for the satellite based retrieval of solar surface irradiance - a LUT based eigenvector hybrid approach. , 2009 .

[2]  E. Dutton,et al.  Do Satellites Detect Trends in Surface Solar Radiation? , 2004, Science.

[3]  H. Guillard,et al.  A method for the determination of the global solar radiation from meteorological satellite data , 1986 .

[4]  K. Trenberth,et al.  Earth's Global Energy Budget , 2009 .

[5]  A. Evan,et al.  Arguments against a physical long‐term trend in global ISCCP cloud amounts , 2007 .

[6]  B. Barkstrom,et al.  Cloud-Radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment , 1989, Science.

[7]  B. Barkstrom,et al.  Seasonal variation of cloud radiative forcing derived from the Earth Radiation Budget Experiment , 1990 .

[8]  Bruce A. Wielicki,et al.  Surface insolation trends from satellite and ground measurements: Comparisons and challenges , 2009 .

[9]  B. McArthur,et al.  Baseline surface radiation network (BSRN/WCRP) New precision radiometry for climate research , 1998 .

[10]  Patrick Minnis,et al.  Changes in Earth's Albedo Measured by Satellite , 2005, Science.

[11]  Shashi Kumar Gupta.  The NASA/GEWEX Surface Radiation Budget Dataset , 2004 .

[12]  Lucien Wald,et al.  The Operational Calibration of Images Taken in the Visible Channel of the Meteosat Series of Satellites , 2002 .

[13]  Richard Müller,et al.  Spatial and Temporal Homogeneity of Solar Surface Irradiance across Satellite Generations , 2011, Remote. Sens..

[14]  M. Jensen,et al.  Relationship between cloud radiative forcing, cloud fraction and cloud albedo, and new surface-based approach for determining cloud albedo , 2011 .

[15]  Andrew A. Lacis,et al.  Calculation of surface and top of atmosphere radiative fluxes from physical quantities based on ISCCP data sets: 1. Method and sensitivity to input data uncertainties , 1995 .

[16]  Stefan Kinne,et al.  An assessment of radiation budget data provided by the ISCCP and GEWEX‐SRB , 2006 .

[17]  H. Beyer,et al.  Modifications of the Heliosat procedure for irradiance estimates from satellite images , 1996 .

[18]  H. Beyer,et al.  Solar energy assessment using remote sensing technologies , 2003 .

[19]  William B. Rossow,et al.  Calculation of surface and top of atmosphere radiative fluxes from physical quantities based on ISCCP data sets: 2. Validation and first results , 1995 .

[20]  Martin Wild,et al.  Global dimming and brightening: A review , 2009 .

[21]  William B. Rossow,et al.  Measuring cloud properties from space: a review , 1989 .