Introduction
CAVE is an informal record containing radiation and meteorological data for
a number of specific sites having:
- (1) top-of-the-atmosphere (TOA) broadband observations from CERES,
- (2) retrievals of the Surface and Atmospheric Radiation Budget (SARB) -
the CERES vertical profiles of fluxes,
collocated with,
- (3) surface broadband flux measurements from ARM, SURFRAD, CMDL, and BSRN and
- (4)ancillary meteorological data, such as vertical profiles of
temperature and humidity,column integrated aerosol optical depth, and cloud properties.
CAVE aims to build and provide access to a long-term record of (1) thru
(4) beginning on January 1, 1998.
CAVE is maintained by the Clouds and the Earth's Radiant Energy System
(CERES)
through the CERES Surface and Atmospheric Radiation Budget
(SARB)Working Group.(local group only)
The SARB group uses radiative transfer calculations to determine the vertical
profiles of fluxes and the forcing by aerosols and clouds. The long-term CAVE
record provides surface and TOA closure for SARB validation. CERES operated
on the low latitude TRMM (mostly for January to August 1998 and March 2000)
and now observes from the global, sun-synchronous Terra (from February 2000)
and Aqua (from July 2002).
The continuous and geographically dispersed CAVE record is a coarser version
of its more intensive (but now dated) cousin, the CERES ARM GEWEX Experiment
(CAGEX). CAGEX focused on
smaller domains of a few weeks.
What about the surface boundary conditions for radiative transfer? CERES
includes two field deployments (COVE and C-FAR) to determine spectral and
directional boundary conditions at the surface. The CERES Ocean Validation
Experiment (COVE),
makes long-term, detailed measurements of the sea surface from a rigid platform.
A main goal of COVE is the development of an ever sharper ocean spectral BRDF.
For land BRDF, measurements are needed at many points. This was done during the
earlier CERES ARM Radiation Experiment (CARE)
provides helicopter based spectral fluxes and BRDF over ARM SGP
(Oklahoma) from August 1998. Global reference maps of surface optical
properties for CERES SARB calculations are maintained at
(surface
properties homepage).
Much of the data on CAVE is preliminary. For example, note the Formal
Disclaimer in the section on CERES ES8 TOA data; the archived ES8 fluxes
will eventually be superseded by more accurate SSF fluxes for the same
space and time domains. Comments on CAVE data are sincerely requested.
As CAVE develops, we plan to acknowledge more thoroughly the assistance
of researchers associated with ARM, CERES, SUNY Albany, CMDL, INDOEX and
other institutions, who are providing this wealth of scientific information.
Temporal Domain
CAVE is a continuous data stream beginning on 1/1/98. Most surface
data is placed into 30 minute bins. Some is averaged (SIRS is comprised
of 30 minute averages of one minute data) and some is binned (water temperature
at the COVE site which is 1 hour data). The satellite data are instantaneous
snapshots.
Spatial Domain
CAVE uses a score of broadband sites from the Atmospheric Radiation Measurement Program
(ARM) Southern Great Plains (SGP) Cloud and
Radiation Testbed (CART) located in Oklahoma and Kansas. Individual sites worldwide are
supplied by CMDL, ARM, SURFRAD, and BSRN.
Satellite and gridded data are used on a nearest neighbor basis. Each data set has an
information page which alludes to its spatial characteristics.
Any questions, comments or information about these data or this homepage
are greatly appreciated. Please contact CAVE manager David Rutan at David.A.Rutan@nasa.gov
or CERES liaison Tom Charlock Thomas.P.Charlock@nasa.gov
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