The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) announces a new Giovanni data portal (SWDB daily) for visualization of long-term daily Deep Blue aerosol products from the Sea-viewing Wide Field-Of View Sensor (SeaWiFS) mission. Global daily gridded products including aerosol optical thickness and Angstrom exponent over land and ocean are available at both 0.5 and 1-degree resolutions from 1997 through 2010. This data was produced by the “Consistent Long-Term Aerosol Data Records over Land and Ocean from SeaWIFS” project led by Dr. Christina Hsu, as part of the Making Earth Science data records for Use in Research for Earth Science (MEaSUREs) program.
SeaWiFS was launched in late 1997 and provided exceptionally well-calibrated top-of-atmosphere radiance data until December 2010, more than 13 years. This data is partnered with an expanded Deep Blue algorithm and the new SeaWiFS Ocean Aerosol Retrieval (SOAR) algorithm. In accordance with Deep Blue’s original focus, the latest algorithm retrieves aerosol properties not only over bright desert surfaces, but also vegetated surfaces. The new SOAR algorithm completes the picture with retrievals over oceans and inland water bodies. With this combination of a long time series and global algorithms, we can finally identify the changing patterns of regional aerosol loading and provide insight into long-term variability and trends of aerosols on regional and global scales.
Giovanni is a Web-based application developed by the GES DISC that provides a simple and intuitive way to visualize, analyze, and access Earth science remote sensing data. For instance, the combination of Giovanni and the SeaWiFS Deep Blue aerosol products allows adept investigation of dust transport from the Sahara Desert to the Caribbean Islands in multiple ways. Figure 1 is a series of natural color images from SeaWiFS for July 23-27, 2006 following a large dust plume from its source in north Africa westward to the Caribbean Islands. Using Giovanni, the aerosol optical thickness for this event can be quickly visualized using the SeaWiFS Deep Blue aerosol products, as shown in Figure 2. Giovanni also provides the ability to plot time series over user-specified regions. Figure 3 is the time series of daily aerosol optical thickness for 2006 over a region covering Haiti and the Dominican Republic and shows the scale, seasonality, and duration of these types of transoceanic dust transport events.
The SeaWiFS Deep Blue Giovanni portal for daily products can be found at:
Monthly SeaWiFS Deep Blue aerosol products will be available in Giovanni next month.
Figure 1. Natural color images from SeaWiFS for July 23, 2006 (at top) to July 27, 2006 (at bottom) showing the progression of a dust plume from north Africa to the Caribbean Islands. Click on the image to see a much larger version.
Figure 2. Average aerosol optical thickness at 550nm over the period of July 23-27, 2006 from Giovanni, using SeaWiFS Deep Blue aerosol data. (Click on the image to view it full-size.)
Figure 3. Time series of aerosol optical thickness at 550nm from SeaWiFS Deep Blue aerosol products for 2006, averaged over a spatial domain including Haiti and Dominican Republic by Giovanni.
Bettenhausen, C, Hsu, N C, Sayer, A M, Huang, J, Gautam, R (2011), Validating and improving long-term aerosol data records from SeaWiFS, Abstract IN21A-1403, presented at 2011 AGU Fall Meeting, December 5-9, 2011, San Francisco, CA.
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Kunhikrishnan, T., J. Wei, G. Leptoukh, C. Bettenhausen, A. M. Sayer, and C. Hsu (2011): Global Deep Blue Aerosol climatology from SeaWiFS in comparison to MODIS: Evaluation, Variability and Applications. [View poster]
, Abstract A53C-0359, presented at 2011 AGU Fall Meeting, December 5-9, 2011, San Francisco, CA.
Sayer, A. M., N. C. Hsu, C. Bettenhausen, Z. Ahmad, B. N. Holben, A. Smirnov, G. E. Thomas, and J. Zhang (2012) SeaWiFS Ocean Aerosol Retrieval (SOAR): algorithm, validation, and comparison with other datasets. J. Geophys. Res, doi: 10.1029/2011JD016599, in press.
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