Saharan Dust Arrives in Puerto Rico


Most recent post at:

Also, come to my latest post on this for today’s Sahara Dust episode:

Some observed Saharan Dust noted in post on June 29, 2019.  Visibility down to 9 miles in San Juan in the 30th.

Links to sources of data:  updated May 2019:

Movie:  Satellite data process to show stable air coming from the Sahara Desert:

EQB public Air Quality Index site:

Naval Research Laboratory site:

Click on NAPPS –> current –>tropical Atlantic

Composite NRL satellite data summary:

NRL web site for aerosol measurements via solar irradiance:

Measured aerosols via solar irradiance:

Montserrat Volcanic Observatory:

Satellite Observations of Volcanic Ash:

Trajectories web site (READY)

TOMS Satellite aerosol site: (inactive)

National Weather Service Map Discussion – look esp. in aviation section

Check more recent posts at this site for more recent maps and information.

Movie of photos from the new GOES geostationary weather satellite centered on Puerto Rico.  The tan-shaded area around it is the Saharan Dust layer. June 13, 2018

June 13th update… While the Saharan Dust storm is not as thick as the continent-wide storm on Mars, it’s still pretty impressive.  This morning, visibility in San Juan dropped to 7 miles and air quality for PM-10 (particulate matter less than 10 microns in size) has deteriorated, approaching unhealthy for sensitive individuals.  The visibility decreased as the morning sun warmed the surface and the rising air mixed down the dust-laden air above the surface.   sahara dust june 2018

This photo from the GOES satellite shows how the dust can show up in the right sunlight angles – look at the hazy area marked with the tan line.  The blue arrow points to Puerto Rico.

US Navy models are predicting over 160 micrograms per cubic meter of dust in air at the surface today. That, if sustained for 24 hours, would be unhealthy for sensitive individuals.

On Mars today, the Opportunity rover didn’t respond to the latest calls from earth.   That may mean it has gone into a low power mode because of the lack of solar energy.  NASA/JPL will have a presentation on this at 1:30pm EDT today.

Dust storms are a problem on our planet, too.  Dust from the Saharan Desert can travel  from Africa across the Atlantic Ocean to Puerto Rico.  A Sahara Dust episode is in progress now in the West Indies.

Data from the Meteosat-9 weather observing satellite is processed to identify areas of air that has come from the Saharan Desert.  Here’s a link to the movie version of the satellite data in this analysis:

The areas in red have very dry, stable air from the Saharan Desert.

Dust from the Sahara can travel into the southeastern United States and Texas.  Analysis of data from air pollution samplers have identified dust from the Sahara even in New Jersey, on rare occasions.

Saharan Dust can reduce visibility (as is it today in San Juan, Puerto Rico), and at high concentrations cause health effects and hinder coral growth. The stable, dusty air also suppresses hurricane formation.

The US Navy is very concerned about dust in the ocean air – I assume because it makes it easier for enemies to hide.  So they’ve done a lot of work on Saharan Dust and other aerosols that reduce visibility.

The lower left panel is predicted concentrations of dust at the surface, in micrograms of dust per cubic meter of air.  Concentrations over 150 ug/m3 can be harmful to sensitive individuals. 

Here’s some links to articles about Saharan Dust in the local press:  (right click to open the link in a separate browser window)

These give some idea of the impact on the West Indies islands.  Some of the information is speculative, so don’t count on all of the science in these articles being correct.

Science articles:

Links to other maps:

Plots of satellite detection of dust:

Computer forecasts of dust concentrations:

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