The Multi-sensor Aerosol Products Sampling System (MAPSS) enables comparative analysis of aerosol retrievals from multiple spaceborne sensors, including MODIS-Terra and MODIS-Aqua, MISR, OMI, POLDER, CALIOP, SeaWiFS, and VIIRS (acronyms defined below), based on collocating these spaceborne data with ground-based aerosol observations from the Aerosol Robotic Network (AERONET) stations. However, exploring and reporting numerous statistical results generated by MAPSS analysis, over a broad range of sensors and hundreds of AERONET stations, is not trivial and pushes the boundaries of what is possible within the framework of traditional academic publications.
With this challenge in mind, we have developed the MAPSS Statistical Explorer Web tool. The tool enables interactive exploration of the statistical results from MAPSS, for the coherent analysis of uncertainty in spaceborne aerosol retrievals over AERONET and other ground stations. All aerosol ground stations are displayed on a Google map. By clicking a given site, a panel pops up showing the values of an uncertainty parameter (e.g., R2, slope, offset, , and root mean square (rms) error) for all sensors compared to AERONET. Options are comparisons in different seasons, with or without quality analysis (QA) filtering, and including or excluding distinct outliers. In addition to the statistics presented in the panel, a user can also obtain scatter plots, time-series plots, or relevant data files, enabling further exploration of uncertainties that might exist in spaceborne retrievals corresponding to a given site.
In the example MAPSS Statistical Explorer screenshot accompanying this article [click to make larger], a color-coded circle shows coefficients of determination (R2) of the linear least squares regression fits of each sensor aerosol optical depth (AOD) against that of the Goddard Space Flight Center (GSFC) AERONET station located in Greenbelt, Maryland. Colors and symbols are explained below the map. The bottom right circular chart shows the average R2 values based on all AERONET stations globally.
The MAPSS Statistical Explorer can be accessed from the Giovanni home page, http://giovanni.gsfc.nasa.gov/, under “Atmospheric Portals,” or directly at http://giovanni.gsfc.nasa.gov/mapss_explorer/.
For additional information about the MAPSS system and data, please refer to the MAPSS (http://giovanni.gsfc.nasa.gov/mapss/) and AeroStat (http://giovanni.gsfc.nasa.gov/aerostat/) portals in Giovanni.