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It's an ill wind that blows no man any good


old man emu
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I was driving past the ghost town known as Kingsford-Smith Airport today when the thought struck me that the COVID wind might be doing no good for most of us, but I wonder if the lack of air traffic using the airport is resulting in a lessening of the stress levels of the blokes up in the tower who are usually juggling many aircraft at the one time.

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It's nice in some ways that the skies above the city are a lot quieter than they used to be. There always used to be quite a few whiney jets circling around most days.

But now, all we get mostly is the copper chopper some nights, the odd police 'plane, the occasional Westpac Jetranger emergency flight - and there's a medium-sized piston twin that hangs around a bit, often going in many different directions at about 1200-1500', day and night, and I suspect it's an IFR training aircraft. But Perth airport is very quiet, compared to B.C. (before COVID).

Someone comes in fairly regularly in a particularly noisy twin business jet, that is irritating. It really howls with a penetrating whine.

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12 hours ago, nomadpete said:

And we haven't heard any comment from climate scientists - has the dramatic cuts to high altitude polluters (jet aircraft) resulted in any measurable changes to climate/CO2/etc ?

Is anyone overjoyed by the reduction of contrails poisoning us??

I doubt if the reduction in high altitude flights over the past 12 months would measurably change atmospheric parameters. It takes a long time for chemicals from fuel combustion to dissipate. But when you compare the pollution from aviation to pollution caused by volcanic eruptions, aviation runs a distant second place.

 

The year 1816 is known as the Year Without a Summer because of severe climate abnormalities that caused average global temperatures to decrease by 0.4–0.7 °C (0.7–1 °F). Summer temperatures in Europe were the coldest on record between the years of 1766–2000. This resulted in major food shortages across the Northern Hemisphere. Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in April in the Dutch East Indies. This eruption was the largest in at least 1,300 years (after the hypothesized eruption causing the extreme weather events of 535–536), and was perhaps exacerbated by the 1814 eruption of Mayon in the Philippines.

 

The fact that the eruption occurred north of the Equator seem to mean that its effects were minimal in the Southern Hemisphere. 1815 was the middle of the Macquarie Governorship. We'd have to dive into its archives to see what effect the eruption had on the Colony. 

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7 hours ago, nomadpete said:

The reason I asked, was because following the grounding of All aircraft, post the twin towers collapse, back in 2001 there was a reported temporary change in temps across USA.

You'd have to look at a lot of concurrent factors to support the theory that the decrease in air traffic lead to a change in recorded temperatures. I'd like to see temperatures for Europe included. Also, how much did the temperatures deviate from say, the average of 1990 -2000. 9/11 happened at the start of the Northern Hemisphere autumn/winter. Were there expectations in the late Northern summer of 2001 that a mild autumn/ winter was expected? 

 

Once again we must enquire into who was making the claim. It could have been an abuse of statistics, just as much as it could have been true.

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Is this the misuse of statistics?

 

From https://www.sciencedaily.com/releases/2002/08/020808075457.htm


"We show that there was an anomalous increase in the average diurnal temperature range for the period Sept. 11-14, 2001," the researchers reported in today's (Aug. 😎 issue of the journal Nature. "Because persisting contrails can reduce the transfer of both incoming solar and outgoing infrared radiation and so reduce the daily temperature range, we attribute at least a portion of this anomaly to the absence of contrails."

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They also said....

 

The change in the temperature difference was plus 1.1 degree Celsius, equal to plus 2 degrees Fahrenheit, above the 30-year long-term mean diurnal temperature range. The researchers compared the temperature ranges on these three days to those of the three days directly before Sept. 11 and the three days after Sept. 14, finding that the days before and after were similar, but that the three days in question differed by 1.8 degrees Celsius

 

 

That's a significant change for those days, bracketed by statistically normal temperatures either side...

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I wouldn't call it a misuse of statistics, because it doesn't draw a conclusion that the removal of jet trafiic increases global average temperatures or the application of contrails will solve it. It states quite clearly it is localised diurnal temperature changes due to the removal of what is in effect an insulator.

 

Although the click-bait headline is a little misleading...

 

 

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9 hours ago, nomadpete said:

Is this the misuse of statistics?

Not when you supplied the reference source, and the reference clearly indicates that the results were based on a review of a 9 day period. Clearly there is a strong inference that the combustion products left behind aircraft at high altitudes do create a blanketing effect, and one can surmise that the more flights, the more blanketing. 

 

On 02/10/2021 at 9:19 PM, spacesailor said:

We here in Sydney have noticed a Lot of clear skies.

No brown haze over the city.

We also have had extremely high west/south-westerly winds which are normal for this time of year. Those winds carry the pollution out to sea and replace the polluted air with cleaner air. However, I have noticed that since the lockdown, the amount of household dust has decreased significantly in my house. I put this down to the reduced traffic flow on the street where I live. I have schools in both directions along the road which have been closed, so I am not getting all the yummy mummies driving past on the way to drop their grubby bubbies off at school.

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Interesting article below about how the South Pole has just had its coldest Winter on record - to naturally balance out the warmest and driest Summer on record for the Northern Hemisphere.

But of course, every single one of these articles always comes complete with the paragraph, that no major increase in cold recorded anywhere, has any effect on the march of Global Warming, it's always just an anomaly. 

 

https://www.seattletimes.com/nation-world/south-pole-posts-most-severe-cold-season-on-record-an-anomaly-in-a-warming-world/

 

 

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ALL flights are not equal in the making of contrails .  Some planning goes a  different route to avoid areas where it will form. Where you have Cirrus cloud it's all ice crystals. Though very dry you still need H2O to form the contrails from the combustion of the hydrocarbons but Contrails do not form all the time even though what comes out the back doesn't vary much to account for it. Nev

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There's not much material in any cirrus cloud. It's composed of very thin crystals that you can see through when you're at their level.

  Anvil Cirrus blown out of the top of a monster CB is a different matter and can hide HAIL so don't go near it downwind of it.  Give it a 20 NM berth. Nev

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It's really incredible to think of the amount of water in a cloud. Even a small , isolated thunderstorm can drop millions of litres of water in a few minutes. With a rainfall of 1 mm, rainfall of 1 mm supplies 0.001 m^3, or 1 litre of water to each square metre of the field.

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It really depends on the cloud and the updrafts in it. Tropical maritime air contains the most moisture and that moisture powers the updrafts using the latent heat of vaporisation of water. released as the vapor turns to water. When water drops from a cloud is when the terminal velocity of the drops exceeds the velocity of the rising column in the cloud. Nev

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