HR: 17:45h
AN: A54D-07 INVITED     [Abstracts]
TI: Interannual Variability in Ground-based Surface Radiation Budget-related Data Records
AU: * Dutton, E G
EM: ells.dutton@noaa.gov
AF: NOAA, Oceanic and Atmos Research, R/CMDL1 325 Broadway, Boulder, CO 80503 United States
AU: Wild, M
EM: martin.wild@env.ethz.ch
AF: Inst. for Atmos and Climate Science, Swiss Federal Inst of Technology, ETH Centrum, Universit„tsstr.16 CH-8092 Zurich, Switzerland, Zurich, CH-8092 Switzerland
AB: The interannual variability of several ground-based surface radiation budget-related records is examined. These records include solar and infrared irradiance, clear-sky transmission, aerosol optical depth, total effective cloud transmission, and cloud frequency all as determined at 5 globally remote climate monitoring observatories. Other ground-based solar irradiance records from various locations around the globe are also investigated. The durations of the records range from nearly 50 years in the case of a highly-precise clear-sky transmission record to about 13 years for the infrared irradiances. The purpose of this investigation is to look for similarities with, or other evidence relating to, widespread reports of significant downward trends in surface solar irradiance between about 1960 and 1992, and to evaluate more recent data. While the potential for small negative trends in solar irradiance prior to about 1992 cannot be eliminated in most of the remote climate observatory data sets, it is definitively demonstrated that such trends do not continue past about 1992 at these sites, collectively or individually, with the notable exception of the one Arctic site. However, other interannually autocorrelated variations are detected that can be reasonably represented with 2nd and 3rd degree polynomials with suggestions of similarity in those signals between all but the Arctic site. Examinations of the clear-sky transmission and aerosol records suggest that clouds may be the major source of the autocorrelated variations. Semi-independent time-series of inferred cloud properties, transmission and frequency of occurrence, tend to support that suggestion. The spatial representativeness of the ground-based solar irradiance data is established, on interannual time scales, by computing cross-correlations between time series for those sites with the spatially unbiased satellite based estimates for the globe. This auto correlation shows that the five sites can be considered representative of up to 20% - 25% of the planet's surface area.
DE: 0321 Cloud/radiation interaction
DE: 0360 Radiation: transmission and scattering
DE: 0394 Instruments and techniques
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 3359 Radiative processes
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005