92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012
Analysis of S'COOL Participant Ground Observations Vs. Corresponding Satellite Data: Cloud Layers
Hall E (New Orleans Convention Center )
Sarah A. Crecelius, NASA/LaRC, Hampton, Virginia; and L. H. Chambers, T. M. Rogerson, and D. R. Doelling

The CERES (Clouds and the Earth's Radiant Energy Ssytem) S'COOL (Students' Cloud Observations Online) Project aims at getting students and citizen scientists involved in real world science. K-12+ students gather and report cloud observations within +/-15 minutes of the satellite's passage to help NASA scientists with ground truthing satellite observations. Ground reports are then matched with corresponding satellite data, combined with a MODIS image of the observation area, and returned to the students to visualize and analyze agreement/disagreement between the matches. Similarly, by analyzing ground observations and corresponding satellite data, members of the S'COOL Team (Chambers, Crecelius, Rogerson) have been able to clarify what satellite attributes provide the best results; meaning legitimate matches between ground observations and corresponding satellite data. Data analysis has already led to a revision in the satellite scan data collected for the observation area. The current interest is the accuracy to which the cloud layers observed match between satellites and ground observations.

The S'COOL project references several satellites when matching participant ground observations to satellite data, including Aqua and Terra. Data products from the CERES instrument aboard these two satellites are being used to analyze the cloud layer aspect of S'COOL observations. Terra data (2001-2011) and Aqua data (2002-2011) from the S'COOL web site (http://science-edu.larc.nasa.gov/SCOOL/usedata.html) were analyzed. To reference an AMS abstract from 2008, “…spreadsheets are set up to allow participating classrooms to paste in a particular dataset of interest, using the standard S'COOL format, and easily perform a variety of analyses and comparisons of the ground cloud observation reports and their correspondence with the satellite data”, this includes cloud frequency, cloud layers, and cloud cover. Additional analysis is being preformed to look at observations and the satellite datasets under the best conditions. Best conditions are defined as a satellite viewing zenith angle of less than 45 degrees, opaque clouds, and overcast cloud cover. CALIPSO satellite data (Doelling) will be integrated and used as additional reference satellite data providing strong information about cloud layering.

This paper will examine the relationship between cloud layer observations when ground and satellite observations are analogous. The hypothesis is that observations are skewed most at times of opaque, low level cloud cases in ground observations or opaque, high level cloud cases in satellite observations because these clouds block the other layers from view. With this knowledge, we can assess which satellite matches S'COOL ground observations the closest in reference to cloud layers and confirm data credibility through comparison with CALIPSO cloud layer data. Future plans include implementing algorithms or comments on the S'COOL web site that participants can apply to their reports when opaque, low level cloud or opaque high level cloud cases exist.

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