Yosemite Contrail Grid 17 June 2015

Chew

Senior Member.
Taken from Glacier Point ( 37.73083, -119.57278 ) at 09:44:29 PDT (16:44:29 UTC) with an iPhone 4. Center of image is azimuth 080°.

Yosemite.JPG
 

Mick West

Administrator
Staff member
The distinctive skyline allows us to make a near perfect match in Google Earth (.kmz attached). I moved the viewpoint a few feet (to 37.730183°, -119.573721°) to stop GE putting it down the cliff face.


Center of image is azimuth 080°.
The GE match above has it at 78.9, so basically the same.
 

Attachments

  • Yosemite Grid Photo.kmz
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Mick West

Administrator
Staff member
Here I've added the tracks of several planes that flew overhead in the 45 minutes preceding this image.


Notice all the flights are bunched up on the left (the north. This makes perfect sense with the tracks being blown south, you can see the tracks to the south are older.

I've not got most of the North/South traffic, as it was out of range on my filter (just set for overhead traffic)
 

Attachments

  • Yosemite grid photo and tracks.kmz
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Mick West

Administrator
Staff member
Intresting looking at the traffic approaching SFO:



None of those very large S-turns contribute to what we see there. See in the viewpoint, the place where they all come together is only just visible about the horizon. But it's an interesting mess of turns. Presumably this is for spacing arriving flights - but I wonder if they were all pushed back a bit?
 
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Mick West

Administrator
Staff member
But what we are really interested in:


Again, the wind is blowing from the North, so the trails will drift from left to right here, as evidenced by the thicker older trails on the right.

Update: as seen in the video below, the wind is blowing from the North West, but the effect on the "vertical" trails is the same. However the "horizontal" trails move a lot more.
 
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Fin

Member
So that's the vertical streaks covered. There also appear to be many horizontal ones. Are we missing these just due to the data being unavailable?
 

Mick West

Administrator
Staff member
So that's the vertical streaks covered. There also appear to be many horizontal ones. Are we missing these just due to the data being unavailable?

No, as I noted above:
I've not got most of the North/South traffic, as it was out of range on my filter (just set for overhead traffic)

I'd set a filter for a 20 mile radius from the approximate viewpoint, unfortunately most of the N/S traffic in the shot was in the range 20-60 miles away.



I'll have a better bash at this tomorrow.
 

Mick West

Administrator
Staff member
Here you go:

And attached
 

Attachments

  • Yosemite Park | Half Dome Time-Lapse Movies Jun 17 2015.mp4
    7 MB · Views: 813

scombrid

Senior Member.
I can attest having ridden from Orlando to SFO in August of 2010, 2011, 2012, 2013, 2014 that I always sit on the right hand side of the plane so that I can get a view of Yosemite on the way in. Of those 5 trips 2 were direct MCO-SFO, two were MCO-ATL-SFO, one was MCO-DEN-SFO. All crossed the Sierra in roughly the place giving me a good view of Yosemite from the starboard side.

I have also experienced the S-turns. I presumed that we were wasting time to space out arrivals. Those are cool animations of the approach.
 

Chew

Senior Member.
From the Apr 27, 2015 video here's a nice whatchamacallit of the Sun at almost the center of the screen. The azimuth of the Sun at that time was 094.6°.

ahw_2015_04_27.mp4_snapshot_00.11_[2015.06.22_08.01.35].jpg
 

Trailspotter

Senior Member.
Intresting looking at the traffic approaching SFO:



None of those very large S-turns contribute to what we see there. See in the viewpoint, the place where they all come together is only just visible about the horizon. But it's an interesting mess of turns. Presumably this is for spacing arriving flights - but I wonder if they were all pushed back a bit?

Previously, in the Redding contrails' tread, we saw a similar way of spacing flights arriving to SFO from the North East direction:
https://www.metabunk.org/mass-obscu...ding-to-cloudy-skies.t6198/page-3#post-152765
This poses an interesting question about the efficiency of this flight spacing system: does it allow to form a single stream of traffic without holding occasional arriving aircraft near the airport?
 
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