Talk:Goddard DAAC Air Pollution Event Search Tool

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Event Search Tool

Your Mirador search interface using an event gazetteer is an interesting and potentially useful way to search for air quality data. The key air quality events include smoke from fires, dust plumes, and urban haze events. A good summary of air quality events is provided on an aerosol events site created by Rudy Husar, also with CAPITA at Washington University:

The NASA Earth Observatory has also cataloged images of dust, fire and smoke.

Querying by location, time and/or pollutant concentration is useful for researchers and others familiar with air quality data. But for people not familiar with what PM2.5 is or the significance of 65 ug/m3, searching by event type is useful. The challenge, as I'm sure you've encountered with the weather events, is how to characterize events for querying observation data. How does your search tool work? Can you provide an example of how a user might search for weather event data? Stefan Falke (Sfalke)


The Mirador test page, which currently provides an interface for event searching is:

The interface provides four prompts: Keywords, Location, Events, Time Span.

To locate the Feb 19, 2004 dust event:

  • Enter Keywords: "MYD021KM"
  • Leave Location blank.
  • Enter "Pm10%HIGH WINDS" (Enter exactly as written to the left, we are not case insensitive yet:))
  • Leave Time Span blank.

A new page will list one collection. Click on the "List selected files by time" button.

Click on the image for: 2004-02-19 19:50:00 MYD021KM.A2004050.1945.004.2004052034748.hdf

The event search is currently a substring case-sensitive search. (We will change this to a case insensitive full text search, soon!)

Below are the events that most frequently intersect MODIS and AIRS data and are current available in Mirador:


  • Air Pollution Particulate Matter (Pm2.5 15.5 - 40.4 ug/m3) Moderate
  • Air Pollution Ozone (O3 0.065 - 0.084 ppm) Moderate
  • Air Pollution Particulate Matter (Pm10 55 - 154 ug/m3) Moderate
  • Air Pollution Particulate Matter (Pm2.5 40.5 - 65.4 ug/m3) Unhealthy for sensitive group
  • Air Pollution Sulfur Dioxide (SO2 0.035 - 0.144 ppm) Moderate
  • Air Pollution Carbon Monoxide (CO 4.5 - 9.4 ppm) Moderate
  • Air Pollution Ozone (O3 0.085 - 0.104 ppm) Unhealthy for sensitive groups
  • Air Pollution Particulate Matter (Pm2.5 65.5 - 150.4 ug/m3) Unhealthy
  • HAIL (0.75 inches)
  • TSTM WIND (50 knots)
  • Air Pollution Sulfur Dioxide (SO2 >= 0.805) Hazardous
  • Air Pollution Particulate Matter (Pm2.5 15.5 - 40.4 ug/m3) Moderate SAHARA DUST
  • Air Pollution Particulate Matter (Pm2.5 15.5 - 40.4 ug/m3) Moderate PRESCRIBED BURNING
  • Air Pollution Sulfur Dioxide (SO2 0.145 - 0.224 ppm) Unhealthy for sensitive groups
  • TORNADO (0 f scale)
  • KARL Extratropical Storm 11 79

Full list of events is in media:events.xls.

Event definitions:

EPA AQS data was used to define "Air Pollution" events. I only defined events for parameters listed in the Breakpoints for the AQI table listed in Federal Register August 4, 1999. (CO, O3, NO2, SO2, PM10, Pm2.5)

The FR's table doesn't list anything between Very unhealthy and Hazardous. In cases where values fell into these ranges I defined the event as Very unhealthy. (e.g. S02 0.605-0.804 ppm)

For PM measurements, I used only PM2.5 - Local Conditions (88101) and PM10 Total 0-10um (81102).

In instances where a qualifier (e.g. PRESCRIBED BURNING, SAHARA DUST) was present, it was included in the event name.

For "Air Pollution" events, the spatial boundary of the event is the site's lat/lon, and the temporal boundary of the event is the beginning / ending time range where the measurements was within the events range.

During a search the event's lat/lon and beginning/ending time ranges are used to intersect a data file's lat/lon and time ranges.

All AQI components have been loaded into Mirador for the year 2004. For 2005, only Carbon Monoxide, Nitrogen Dioxide, and Ozone have been loaded.

Additionally, NOAA's storm event database has been loaded events since 1997, where the event has valid lat/lon coordinates. Only about 2/3 or the storm entries have valid coordinates.

Lastly, NOAA's Atlantic Hurricane database is also included and contains tropical storms and hurricanes back to 1970.

Peter MacHarrie pmacharr