Mysteries, Chemtrails, Aerosols :: Mysterious NZ

[Hector]

Today is not the best blue sky day everywhere in New Zealand, but viewing should be good in Nelson and Manawatu. I predict that you will not see any contrails today, and the following charts explain why.


At Whenuapai (this is the midnight sounding - I don't know why Uni of Wyoming are mis-timing this data) the contrail height range is 27800 to 32700 feet. This is a bit below the normal cruise height for jets. If a plane is climbing thrugh these heights, or cruising around F290 to F330 (29000 to 33000 feet) you will see contrails but only over northern New Zealand.


At Paraparaumu the temperture is too warm and above the Critical temperature at all alitiudes. You will not see any contrails over central New Zealand today.


At invercargill there is a shallow contrail layer between 21000 and 24000 feet. This is well below the cruise height for high bypass jets, although you might catch a contrail if you see a plane climbing through this layer. This is the cruise height range of the smaller turbo-prop (no bypass) planes, but the contrail factor for that engine type is lower and the critical temperature is colder, so you won't see any contrails from them either. In fact you rarely do.

Of course if the atmosphere cools a bit, the temperature may dip below the ctritical temperture. The upper winds are all westerly so I doubt that there will be much change in the temperature.

Please disregard the flight level and pressure scale I am building on the right side.

I wanted to get these charts up to show that this analysis can confirm the presence of jet engine exhaust condensation trails as well as demonstrate why and when they will not occur. It has to work both ways to be convincing and credible diagnosis method.
:D
"The truth is out there" for all to access ... if they want to.

[Hector]

Here are the midday temperature soundings from Whenuapai, Paraparaumu and Invercargill for Sunday 13 August 2006.
I have linked the smaller size version of the images here. These are still readable, and you can see the full size ones in the Gallery
http://www.mysteriousnewzealand.co.nz/photogallery/thumbnails.php?album=46





Not much change from midnight (see above).

The contrail height range is too low for normal jet cruise heights, and so thin it is almost not there at all over central and southern New Zealand.

You won't see contrails today, except perhaps over the north of New Zealand. There, the jet would need to be in the height range from 28000 to 33000 feet to be producing a contrail.

[Deano]

Too windy and cloudy (heavy gusts, sporadic rain) in the Manawatu to give accurate observations, no noticeable contrails or chemtrails.

[Hector]

Thank you for the report on your observtion, Deano.

We still havn't heard from the Nelson people.

Actually, today was a contrail day over central NZ (based on the Paraparaumu sounding). The bottom boundary was F281, that is flight level 281 or 28,100 feet. I was in Wellington and didn't see any. The Auckland-Christchurch route is over D'Urville Island and the upper wind was a light easterly, so thay may have been hidden below the hills on my western horizon.
If there were any, the Nelson people would have been able to see them.

[Deano]

These last couple of months have seen a huge decline in activity. Days like today and yesterday would have been perfect windows for any activity but nothing. One or two quickly dissapating contrails over the coast but nothing suspicious.

[Hector]

Thank you for your observation, Deano. I saw one as well, low on the western horizon from Wellington.

Today will be another jet exhaust condensation day over central NZ and probably right up to Auckland. There is not enough moisture for them to be persistent, and they will be over the coast or out over the South Traranaki Bight. I think the lower boundaty is a bit higher today (I have not done a detailed analysis) so they may be intermittent - or not at all. :(

It will be cloudy over Nelson, but I would appreciate any reports from further north to verify this prediction. 8)

Actually, if you are out bright an early this morning you will see exactly the same phenomenon when you breathe out. Hoooh! Contrail! but only transient. More persistent in foggy Waikato. Also when you boil your kettle, start your car - same thing. It's just condensed water vapour.

[Hector]

What a day! We were not in Wellington, but driving to Hastings...

12:10pm: From Masterton (just north of town on SH2) We saw, almost overhead, a continuous jet engine exhaust consensation cloud casting a shaddow on a layer of cirrus barely a few 100 metres lower than the plane.
The plane was moving approximately south-southwest. In binoculars I could clearly see that it was a large 4-engine jet. The cloud was obscured within about 15 minutes by the thickening cloud layer beneath it, although we were driving away to the west-northwest.

2:05pm: Norsewood (5 km north of the town on SH2) Near the horizon approximately northwest, I saw an intermittent transient jet engine exhaust consensation cloud from a plane moving south.

3:25pm: Hastings (Angus Hotel car park) Looking west near the horizon, I saw an intermittent (it covered an arc of about 45 degrees) but fairly persistent jet engine exhaust consensation cloud possibly 30 minutes old at the time. It finally dissipated (as far as I could tell) about 4:15pm.

5:25pm: Hastings (Angus Hotel car park) Looking to the west-northwest near the horizon, possible jet engine exhaust consensation clouds... about three.

I bought a camera in Masterton, and I will post them when I 'download' the images.

I see in another post this morning that there were a lot of jet engine exhaust consensation cloud in Taranaki.

So the day was much better thn I expected. I under forecast it somewhat from the once-over-lightly analysis I did early this morning.