Home -- ENSO Cycle -- ENSO Effects -- Missions -- Data -- Tools -- Site Map Data Provided -- Sample Information -- How To Order -- Local Links -- Web Links

Table showing data processing levels

Top of Page

The samples were downloaded (cut and paste) from a database site at Goddard Space Flight Center (Code 916).

The sample for each date shows where the aerosol index (AI) detected the presence of UV-absorbing tropospheric aerosols. The areas in Africa south of the equator indicate smoke produced by biomass burning. North of the equator, most of the aerosol is due to dust blowing off of desert regions. Dry lake beds contain fine particulate matter that is easily picked up and transported by blowing wind. In Indonesia, fires set to clear the land for farming were not extinguished as usual by the annual monsoon rains. since an El Niño produces dry conditions in the Indonesia region.

The sample dataset contains location data and AI measurements for each sample. The first three lines in the file are header lines, giving the date, data type and Lat/Long grid information. The data is written using Fortran format statements ("25I3" for 11 of the 12 line segments, and "13I3 1A17" for the last segment, which has the latitude information for that line). The first line is the south-most line of the grid, and is fill data: "999". The integer value in the file must be divided by 10 to yield the AI value. A TOMS AI of less than 0.1 indicates a crystal clear sky with maximum visibility, whereas a value of 4 indicates the presence of aerosols so dense one would have difficulty seeing the mid-day sun. The provided sample AI images (above) were custom-produced. The image for Indonesia was produced by using an IDL program to read, subset, and plot the L3 data. The data was color coded and then read into an image with a backgound MODIS "Blue Marble" image. Similar but different processing produced the image for North America.