Following the release of the Giovanni for daily
SeaWiFS Deep Blue aerosol products, the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) announces the release of a new Giovanni portal for visualization and analysis of long-term monthly
Deep Blue aerosol products from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (SWDB_monthly ⇒ http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=SWDB_monthly
Global SeaWiFS Deep Blue monthly gridded products at both 0.5° and 1.0° spatial resolution are aggregated from the daily products, including aerosol optical thickness and Angstrom exponent over land and ocean, , 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. This combination of a long time series and global algorithms makes it possible to finally identify changing patterns of regional aerosol loading and provide insight into long-term variability and trends of aerosols on regional and global scales.
Accessing monthly SeaWiFS Deep Blue aerosol products in Giovanni allows one to easily visualize seasonal and interannual variation of aerosols at global and regional scales. Figures 1a and 1b show sample images of global seasonal mean aerosol optical depth (AOD) at 550 nm generated by using the Lat-Lon Map, Time-averaged function in Giovanni to average the monthly data for spring 2006 (March, April, May) and fall 2006 (September, October, November), respectively.
Figure 1: Global seasonal mean of aerosol optical depth at 550 nm from 1.0 degree resolution monthly SeaWiFS Deep Blue products generated from Giovanni for 2006 (a, left): spring (March, April, May) and (b, right): fall (September, October, November). Click either image to view full-size version.
Giovanni is also able to create time series over user-specified regions. Figure 2a is the time series of monthly AOD at 550 nm from January 2004 to December 2007 over the northern hemisphere land (red line) and ocean (black line), showing clearly the seasonal and interannual variation over both land and ocean. Figure 2b for the southern hemisphere is similar to Figure 2a.. The northern hemisphere land AOD has elevated values in springtime and summertime, which is associated with springtime African/Asian dust, and more haze in populated areas in the summertime. The southern hemisphere AOD exhibits a peak over land from September to November, which is the peak biomass burning season for South America (plus a contribution from African biomass burning). Ocean seasonality is largely driven by outflow from the continents. The southern hemisphere ocean has less seasonality (outside of the biomass burning regions) due to the considerably lower distribution of large continental land masses, and correspondingly lower human population.
More visualization functions, such as animation, scatter plot, and overlay of two parameters, etc. are also available in Giovanni.
Figure 2: Monthly time-series of aerosol optical depth at 550 nm over (a, left): northern hemisphere and (b, right): southern hemisphere for land (red line) and ocean (black line). Click on either image to view the full-size version.
Links and Documentation
The SeaWiFS Deep Blue Giovanni portal for monthly products can be found here:
The daily SeaWiFS Deep Blue aerosol products are available in Giovanni at:
SeaWiFS Deep Blue data products, documentation, and data access methods can be found at the following sites:
Text provided by Dr. Suhung Shen and the Dr. Christina Hsu's MEaSUREs project team. Editing and publishing provided by James Acker.
For more information, please contact the GES DISC Help Desk: email@example.com
Funding for Dr. Hsu's MEaSUREs project and MEaSUREs data at the NASA GES DISC is provided by the NASA MEaSUREs Program.
The GES DISC is a NASA earth science data center, part of the NASA Earth Science Data and Information System (ESDIS) Project.
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