ERBE Temporal Interpolation
ERBE Temporal Interpolation Description
- The CERES instrument onboard
Terra (10:30LT) or
are in sun-synchronous orbits limiting diurnal sampling
- There are no CERES products that combine the Terra and Aqua observations
- ERBE temporal interpolation uses the same historical ERBE temporal interpolation algorithm.
It relies on linear interpolation of cloud properties in the SW and linear interpolation of
LW fluxes except over land when a half sine model is used to model the diurnal heating
(Young et al. 1998)
- This method is insufficient to derive the diurnal signal over regions with strong diurnal cycles include,
maritime stratus region where clouds burn off during the day, land afternoon convective regions,
and land daytime heating
- The SSF1deg
product uses ERBE temporal interpolation
- To take into account the changing meteorology the
(CERES temporal interpolation method)
incorporates 3-hourly geostationary clouds and fluxes to estimate the flux in between CERES measurements
- Examples of ERBE and CERES Temporal Interpolation flux differences
- Comparison of the ERBE and CERES SW flux temporal interpolation over a Peruvian maritime stratus
region over the course of one day.
- Comparison of Terra minus Aqua ERBE temporal interpolation vs Terra minus Aqua CERES temporal
interpolation of monthly mean regional SW fluxes.
- Comparison of ERBE minus CERES temporal interpolation of SW monthly mean regional fluxes.
- Comparison of ERBE and CERES LW flux temporal interpolation over clear-sky desert.
- The CERES LW flux temporal interpolation is not symmetric about noon.
- Comparison of ERBE minus CERES temporal interpolation of LW monthly mean regional fluxes.
ERBE Temporal Interpolation Procedure
- ERBE LW land temporal interpolation uses a half-sine and constant nighttime fit if the
daytime LW flux is greater than the nighttime flux, to fill in 24 hourly time steps during the day
- ERBE LW ocean and snow temporal interpolation uses linear interpolation in between CERES measurements,
to fill in 24 hourly time steps during the day. It is assumed that there are no LW diurnal cycles over
clear-sky ocean and snow surfaces
- ERBE SW temporal interpolation uses directional models based on scene type.
Directional models relate solar zenith angle with albedo. There are ~600
types based on imager cloud properties, geo surface types.
What ever the scene type was at the time of the CERES measurement will select the directional model
to derive fluxes for the rest of the daylight hours.
(Young et al. 1998)
- For most non-polar regions this assumes constant meteorology throughout the day based
on the Terra (10:30 AM sun-synch) or Aqua (1:30PM) measurement time,
since only one daytime measurement is usually observed.
CERES Data Product Information