How are air quality pollutants pollutants measured?
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Pollutant levels, such as that for SO2, are given in units of mass/volume (i.e. densities). These must ultimately be measured using physical sensors somehow, correct?
And if so, at what height are these sensors placed at? And by extension, up to what altitude are these pollutant levels valid for (ex. 200m above the ground? 500m? 1km? etc.)
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@jyscao
Air pollutants on Windy are measured by satellites. So the sensors are placed on satellites at high levels. Data are provided by Copernicus or NASA.https://en.m.wikipedia.org/wiki/Remote_sensing
https://www.esrl.noaa.gov/csd/groups/csd3/instruments/lidar/
The altitude of the chemical plumes detected by satellite depends on the pollutants type but probably more than 1 km.
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@idefix37 thanks for the info, it's really helpful.
The altitude of the chemical plumes detected by satellite depends on the pollutants type but probably more than 1 km.
The pollutant I'm specifically interested in is sulfur dioxide (SO2). And I'd like to be able to get a maximally accurate estimate (with error bounds if possible) for altitude ranges that the stated densities are valid for.
This is the SO2 forecasts from Copernicus: https://atmosphere.copernicus.eu/charts/cams/sulphur-dioxide-forecasts
And this is from NASA: https://so2.gsfc.nasa.gov/
Judging by the recency of data and spatial resolution, I presume windy.com uses data from Copernicus for emitted SO2. If that's indeed the case, do you know I might access the raw SO2 data from either Copernicus or Windy?
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@jyscao
Seems that Windy uses NASA data for SO2.
On website press the small clock in right low corner of your screen to get information about all layers.
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We can see the anomaly in SO2 actual from the NASA data itself: https://so2.gsfc.nasa.gov/pix/special/time_sres/time_series.html
This clearly shows some crazy spikes right then and there for Eastern Asia. Look at the scale, ffs, its off the charts:
And there's also a weird data hole around Feb 2 (0 everywhere).
Doesn't mean we know what it was from, but it cannot be denied that there are/were crazy spikes in SO2 over that region recently.
