Not exactly new news though, several weeks ago perhaps? It happens several
times each summer. its nature at work setting up new ant colonies by moving
new queens into new areas. Not very many of them survive, its a brute force
way of expanding the species.
The detection was done with Doppler Radar from the ground.
Secondary information was provided by IR and visible wavelength
photos of the country from space. Using those photos, there was
insufficient cloud cover, to conclude the Doppler radar could
be imaging rain. So information from space was used but only
as a means to re-enforce what the Doppler saw.
This story (including the same picture) was on my local
news here on July 19th.
Odd that they don't seem to spot all those dingys heading our way
until they have crossed the midpoint of the channel.
I often wonder what would happen if a flotilla of UK inshore
fishing boats got anywhere near the midpoint at about midnight
on a nice calm night. Pretty sure the Frence border force boats
would be out immediately.
Doppler radar is used to image a slice of atmosphere at 10,000 feet.
It doesn't double as a boat-traffic-monitor.
And the overhead surveillance isn't good enough for tracking everything.
It's used for "hot spots". Google Earth has high resolution, but to
update the view of the Earth from space, is taking a year or two.
I don't see anything to suggests the capability is "continuous"
and "real time".
We still fly coastal patrols here, for fisheries compliance.
We wouldn't have to do that if the satellite fleet was "magic".
Dover coastguard operate a very powerful radar system for monitoring
shipping. It is specially designed so it only operates as it
sweeps the 180? degree arc across to Calais but noone in Kent
behind that sender/receiver gets a dose of microwaves.