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S'COOL: Comparing to Satellite Data
In order of timeliness:
Within hours: Comparing to MODIS
The Terra and Aqua spacecraft both carry an imaging instrument: the MODerate
Resolution Imaging Spectroradiometer (MODIS).
Quick-look images are posted for daytime orbits of MODIS on the
MODIS Rapid Response website
about two hours after the time they are taken.
Within a week: Comparing to FLASHFlux
FLASHFlux is a relatively new project which takes the complicated CERES
algorithms, brings in preliminary versions of the other required data
streams, applies a preliminary calibration to the CERES data, and produces cloud
information within a week. The results show up in the S'COOL
Database as soon as they are ready.
Within several months: Comparing to CERES
The goal of the CERES project is to produce climate-quality information.
Thus, great care is taken in the calibration of the CERES instrument.
In addition, the CERES team brings in a large number of other pieces of
information, in order to get the best possible understanding of the Earth's
Radiant Energy. This includes maps of surface vegetation
types, the presence of snow and ice, information from weather models
that tells us about the amount of water vapor and other things in the
atmosphere, etc. Finally, CERES also uses data from the companion
imager instrument (VIRS on TRMM
or MODIS on Terra and Aqua) to do the cloud detection and identification.
(Read about an analysis of cloud properties
obtained without using imager data by a summer intern with the S'COOL Project.)
VIRS and MODIS are the responsibility of other teams of scientists,
and they have to deal with the same issues of calibration, etc, that
we deal with on CERES. The CERES team is the only science team involved with the Terra
and Aqua spacecraft which produces a global
product depending on measurements from more than one instrument.
Once the imager data are ready, we can finally compute cloud properties.
This generally happens several months after the data are taken.
This process is complete on TRMM, which stopped functioning in Spring 2000
(Read about an analysis of the satellite/ground matches
from the TRMM time period.) Data processing is proceeding for Terra
and Aqua. The CERES data also appear in the S'COOL
Database as soon as they are ready.
Comparing to other satellites
In addition to these Terra and Aqua-related sources,
weather satellite imagery for most of the Earth is placed on the web
in near real-time. Check out this list
of links to get a picture that you
can compare to what your students saw from the surface. For those in the
United States,
this site provides real-time imagery and recent loops of geostationary
data.
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