Entries tagged "contrails"
Not too many words needed this morning.
Venus at dawn, over a misty valley. You might just be able to make out Arcturus, hiding behind the broadest part of the middle contrail, near the top left of the picture.
The contrails are aligned broadly southeast-northwest as usual.
And here is how things looked quarter of an hour earlier. Quarter of an hour is a good chunk of time in the dawn business. Arcturus is easier to spot here, nestled in just under the three contrail lines.
We may never know the exact method that the earliest explorers used to find their way, but there is a friendly finger of suspicion that gets pointed regularly at the birds.
Some of the routes used by the pioneers of the Pacific match the migratory routes of the birds exactly.
The route used by the Maori fleet that sailed from Tahiti to New Zealand sometime in the fourteenth century and settled there is the same as that taken by the Long-tailed Cuckoo each September.
I like to think of these earliest navigators. I imagine them gazing…
The northerly winds were carrying high cirrus and contrails down towards the coast this morning. They have brought colder air, as forecast yesterday. This gave us our first frost of the season. The feel and even the sounds of the grass underfoot have a relationship with the direction the air is moving.
Venus and Sirius both beamed at me this morning during my pre-dawn shiver outside. The aircraft were painting a pink path to the continent to escape the autumnal cold. They are of course heading southeast, which I'm sure you checked from the tiny crescent of the moon. Speaking of crescents, this morning calls for a hot croissant.
__________________________________________________________If you look closely at these two pictures you can see how the aircraft contrail cuts the lower cumulus clouds at a slightly different place in the second picture. It is not dramatic, but one clue that the upper winds at the altitude of the aircraft, probably about 35,000 ft, may be moving in a different direction to the lower winds moving the clouds. The upper wind direction is likely to be the more consistent and can be gauged by lining contrails or cirrus clouds up against fixed features like high…
This morning's sun was a strong enough clue, but if we wanted to know which way was southeast then these aircraft contrails are pointing the way to the continent.It looks like a particularly busy morning for aircraft, but this is just a reflection of atmospheric conditions. The hydrogen-rich jet fuel has mixed with oxygen, reacted in the engines and formed, among lots of other lovely and not so lovely things, water. In certain temperatures and humidity levels this water freezes into ice crystals. The high cirrus clouds that we normally see are also composed entirely of ice.The length of time…
Tonight's early evening sky is a feast of cloud types. Cumulus, passing low and darkened by the shade, perhaps the last of the fair-weather clouds for a bit. Higher there is cirrus, cirrostratus and altostratus all heralding the approaching warm front. Thrown in for a bonus there are some contrails from aircraft heading to and from the continent.