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David Doelling, TISA Working Group Chair

Time Interpolation and Spatial Averaging (TISA) CERES group objectives

The TISA objectives are to spatially and temporally average the CERES footprint fluxes and clouds into CERES level-3 daily/monthly gridded products.

The TISA group uses two methods to account for the regional diurnal flux changes in between the CERES satellite observations. The SSF1deg single satellite product fluxes, assumes constant or linear changing meteorology between CERES observations using similar algorithms that ERBE used. The SYN1deg product combines the Terra and Aqua CERES fluxes with geostationary (GEO) derived broadband fluxes to account for the flux variability in between CERES measurements. The TISA group calibrates the GEO visible and IR radiances against MODIS in order for the CERES cloud group to derive consistent GEO and MODIS cloud properties. The GEO radiances are then converted to broadband fluxes using a combination of empirical, theoretical, and CERES angular directional models as a function of the scene/cloud type. Lastly the GEO derived broadband fluxes are normalized regionally with the CERES observed fluxes to maintain the CERES instrument calibration.

  • Improving geostationary multi-band narrowband radiance to broadband flux conversion methods.
  • Pursuing geostationary imager visible calibration techniques that include deep convective cloud, desert and polar ice targets, ray-matched and SNO cross-calibration, and spectral band adjustment factors.
  • Developing the CERES visualization, subsetting and ordering tool for a positive user experience.




NASA Langley Research Center
Mail Stop 420, Hampton, VA 23681-2199



  • BS, Meteorology, University of Utah
  • MS, Atmospheric Science, University of Washington


  • U.S. Department of the Interior William T. Pecora Award
  • NASA Public Service Medal: In recognition of outstanding contributions in developing innovative methodologies and algorithms for deriving cloud and radiation data from satellite observations, 2002


  • CERES TISA and VSO lead
  • GSICS visible sub-group calibration lead
  • Member of the GERB, Megha-tropiques, and CLARREO science teams

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