Sahara dust

[jack.h...@gmail.com]

Sahara dust is a real nuisance at the moment.  It is impossible to keep car windscreens clean.  It is even getting into the door sills and dashboard.

Up here in north Scotland, there has been a run of winds from southerly quarter for days.  It hasn't rained much, but the visibility is poor in haze.

Moreover, my wife - who gets hay (pollen) fever every year around May/June - has a particularly bad attack and almost certainly this dust isn't helping.  A Google search says:

Saharan dust can be harmful to your health. The particles can be breathed in and enter your lungs and blood stream, potentially triggering asthma attacks in people who have asthma and aggravating other respiratory conditions. Saharan dust worsens air quality and increases the levels of particulate matter in the air.

Thee are a few mentions of Sahara dust in the media if you search hard enough, but I'm surprised it hasn't been given more prominence.

The normal explanation for the cause of the dust is strong winds over the desert.  I dispute that.  Very strong convection can reach to 18,000 feet above sea level: convection is a far more likely to be the major cause, although wind undoubtedly plays some part.

Jack

[jack.h...@gmail.com]

I have just realised that there is a direct parallel: MARS.  Strong convection (dust devils) can trigger a planet-wide haze.

Jack

[jack.h...@gmail.com]

  I am beginning to have some ideas about the dust deposits.  In a supermarket car park yesterday, (8 miles away) many cars were similarly affected, so it's not just a local phenomenon.

For perhaps a week, although no rain, we have had North Sea fog (haar) that doesn't always disperse and can last all day.  That probably contains a lot of dust, which readily finds its way into all manner and means of places.

This picture is a little hard to make out but shows the opened rear door area of my car.  It had been cleaned 24 hours earlier, but the dust just re-appeared!

Jack

[Len]

Suprisingly large grains for Saharan dust and not reddish.

Looks more like beach sand to me.

Len

[Graham Easterling]

Air borne beach sand deposit Cornwall

Still avoiding all the showers, currently sunny & 19C. Last rain day 1.5mm on 14th

Glorious down at Sennen yesterday, the sea was incredibly warm (well unusually not cold) for May, on the incoming tide. Not a cloud in the sky at the time.

Plenty of zoom, far end of Sennen & neighbouring Gwenver, a beautiful beach well away from SW waters light shower (storm??!!!) emergency sewage overflows. Little did we know that the much heralded 'clean sweep' would end in such a mess. Mousehole harbour has been basically an open sewer for years since they replaced the old Victorian pipes. Doesn't matter as it isn't a designated bathing beach and there's no checks anywhere nearby, I wonder why. Still, at least I'm not in Brixham. 

Virtually no swell, just a gentle sea breeze ripple.

Graham

Penzance

[jack.h...@gmail.com]

The winds have been south or southeast with the haar being persistent at times.  The merest drizzle from the fog causes the dust to clump.

It is a very widespread phenomenon in this area and I cannot think it's from local sandy shores.  The wind has usually been very gentle and not enough to lift beach sand (which I have certainly seen in the past.)

Wheelie bin lid.

And the roof of my car after attempting to hose it off showing the clumping 

Jack

[Graham Easterling]

My post was very much tongue in cheek!

That certainly looks fairly convincing. As you say, the winds been right.

Graham

[jack.h...@gmail.com]

On Tuesday 21 May 2024 at 17:39:31 UTC+1 Graham Easterling wrote:

My post was very much tongue in cheek!

I realised that your post was in jest Graham, but wasn't sure that Len's follow up referred to the Cornish beach or my dirty car.

Jack 

[Nick Gardner]

Jack

Could it be pollen deposition caused by dew?

Nick

Otter Valley, Devon.

[jack.h...@gmail.com]

Pollen is indeed a possibility, but I wouldn't have though the colour and texture of pollen would be so consistent over such a wide area.  

Jack