WACCM Chemical Map


This is an experimental display. The WACCM Chemical Map shows a merged view of two ACOM data sets:


The map shows red fire icons on top of a shaded overlay representing the concentration of surface ozone (or some other chemical). Each red flame represents a square kilometer in which a wildfire has been detected; a large fire will often show a number of flames in a grid pattern. The colored overlay shows O3 concentrations from highest to lowest in a color scale that ranges from red and green through blue and light purple. The overlay is clear for chemical concentrations below a certain minimum level. There are dense colored contour lines around the extremely high concentrations.

The blue-green flames are fires detected by the MODIS satellite (Moderate Resolution Imaging Spectroradiometer) that have not yet been recorded in the FINN. These preliminary fire detections are downloaded every hour from the web page at NASA (National Aeronautics and Space Administration) for the following MODIS regions: USA (Conterminous) and Hawaii, Canada, and Alaska:
Click on the lone blue-green flame in Hudson Bay to obtain the date and time of the MODIS overlay. Since the red flames are from yesterday and the blue-green flames are for today, their combination can reveal the progress of a wildfire.

The map is initialized to show the western United States, but the overlays cover the entire globe. You may zoom and pan to view other regions of the world using the controls in the lower right-hand corner of the map. The grid resolution is 1.9° in the north-south direction and 2.5° east-west.


The controls below the map are used to bring up a plot of the chemical concentration for the point on which you clicked. The plot type defaults to time series; click on the map, and the upper right-hand corner will display a small plot showing the O3 concentration over time at that location. This first plot is a thumbnail preview; click on the inset plot to bring up a full-size image in a new tab of your browser. Each new tab will remain in your browser bar until you close it.

The chemical concentration is plotted in blue at 6-hour intervals. The dotted red line represents the standard health threshold of 70 ppbv for surface ozone, as measured in an 8-hour average according to the American NAAQS Table of Pollutants.

The software underlying the WACCM Chemical Map uses linear interpolation to calculate the numeric values between grid points. Small differences in the clicked location should produce slightly different plots.

The sounding plot displays the O3 concentration up from the surface to the top of the atmosphere. The NAAQS health standard is plotted in a dotted red vertical line. Concentrations of ozone in the stratosphere (the ozone layer) are typically much greater than at the surface.

The zonal and meridional plots show a vertical cross section centered on the map point at which you clicked. Zonal is from west to east, and meridional is from south to north. The cross-sectional plot displays the O3 concentration with height using a color scale, and the values on that scale are displayed in a color bar on the right-hand side of the plot. Note that a high concentration in the stratsphere will tend to overwhelm the colored concentrations at lower levels in the atmosphere. Profile plots display the surface concentration from west to east (zonal), and from south to north (meridional).

You may turn the overlays on and off using the "Show chemical" pull-down menu. CO fires refers to carbon monoxide emitted from wildfires. Use the Clear plot button to remove the thumbnail.

Refresh Rate

The Google Maps server appears to refresh map overlays once per day. This rate is satisfactory for the red FINN fires, which are updated every 24 hours at 6:55 AM Mountain Time. The blue MODIS fires are retrieved from NASA and updated on the ACOM server every hour at 30 minutes past the hour. Note that the MODIS fire detects displayed here are only as recent as the time-stamp on the NASA web page. For additional visualization, you may download the current fire overlays and view the KMZ files directly with Google Earth or another KML viewer: FINN fires KMZ overlay global, FINN fires KMZ overlay for North America, MODIS fires KMZ overlay. You may also browse ACOM's archive of KMZ fire overlays.

Return to WACCM Chemical Map.