ROCKMAN wrote:Outcast - "Is this the same kind of argument you make in your incessant AGW denial". Are you off you f*cking meds again? LOL. Or have you ever read a single word in any of my dozens of posts where I readily acknowledge AGW? Son, it might be time for you to seek some professional help.
Maybe it's your f*cked up neural pathways that make you see dots between the "L" and the "a". Either that or as the great Texas comedian Ron White has said: "You can't fix stupid." LOL.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Maybe the recent pollution spikes will spur some enforcement.Tanada wrote:There is a fairly high probability that if China really does go into a major economic decline and shuts down many of there coal SOx particulate spewing power plants that are of the older generation the dimming over the Pacific and west coast of the USA will decline.
We know from post September 11, 2001 studies of contrail effects on global dimming can be as much as 1.5 to 2.2 C in impact virtually overnight.
Much of China's fleet of coal plants are modern units fitted with scrubbers, units designed to remove sulphur dioxide, one of the gases blamed for causing acid rain and respiratory illness.
More than 70 percent of the approximately 700 gigawatts of coal-fired power in China have these units, but they cost money to use, adding around 10 percent to operating costs for power generators.
This means that the scrubbers are often not used, and attempts by the authorities to force utilities to turn them on are ignored.
The Washington Post reported in May last year that Huadian, one of China's largest power producers, turned off scrubbers at its plants near Beijing.
Fines levied on offending coal plants are likely to be lower than the cost of operating scrubbers, meaning power companies have little incentive to follow the laws.
Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Outcast_Searcher wrote:Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Interesting. Any idea of the general fuel/economic impact of doing this? If the extra fuel required is minor (percentage wise) then this sounds like a good idea, if you can get the international community to agree on this.
Outcast_Searcher wrote:Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Interesting. Any idea of the general fuel/economic impact of doing this? If the extra fuel required is minor (percentage wise) then this sounds like a good idea, if you can get the international community to agree on this.
Q: In which layer of the atmosphere do we normally see contrails?
A: Contrails usually form in the upper portion of the troposphere and in the lower stratosphere where jet aircraft normally fly, generally between about 8 and 12 km altitude (~26,000 to 39,000 feet). They can also form closer to the ground when the air is very cold and has enough moisture.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Outcast_Searcher wrote:Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Interesting. Any idea of the general fuel/economic impact of doing this? If the extra fuel required is minor (percentage wise) then this sounds like a good idea, if you can get the international community to agree on this.
Aren't the planes still emitting the same stuff? You just won't see the H2O contrails.Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Keith_McClary wrote:Aren't the planes still emitting the same stuff? You just won't see the H2O contrails.Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Keith_McClary wrote:Aren't the planes still emitting the same stuff? You just won't see the H2O contrails.Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
These folks make it seem more complicated:Tanada wrote:Keith_McClary wrote:Aren't the planes still emitting the same stuff? You just won't see the H2O contrails.Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
When all the jets were grounded for three days in 2001 they discovered that Contrails act as heat reflectors at night making the night time temperatures over 1 C warmer on days with contrails than on days without. Their dimming effect in the day is real, but not as large as their warming effect over night.
Keith_McClary wrote:These folks make it seem more complicated:Tanada wrote:Keith_McClary wrote:Aren't the planes still emitting the same stuff? You just won't see the H2O contrails.Tanada wrote:Best solution, require short distance flights to remain below 25,000 feet and require long distance flights to fly at or above 40,000 feet. Contrails almost disappear, no more contrail pollution or global dimming caused.
When all the jets were grounded for three days in 2001 they discovered that Contrails act as heat reflectors at night making the night time temperatures over 1 C warmer on days with contrails than on days without. Their dimming effect in the day is real, but not as large as their warming effect over night.
http://www.nature.com/nclimate/journal/ ... 068.html#/
Contrail cirrus are composed of ice crystals that—similarly to natural cirrus—reflect solar short-wave radiation and trap outgoing long-wave radiation. For fixed ambient conditions, their radiative effect is mainly determined by their coverage and optical depth. Contrail cirrus form and persist in air that is ice-saturated, whereas natural cirrus often require high ice supersaturation to form. This implies that in a substantial fraction of the upper troposphere, contrail cirrus can persist in supersaturated air that is cloud-free, thus increasing high cloud coverage. Remote-sensing studies have estimated line-shaped-contrail coverages as large as a few per cent in regions in which the levels of air traffic are high. The coverage due to contrail cirrus is as yet unknown because they are difficult to distinguish from natural cirrus in satellite observations.
Globally, the long-wave radiative forcing due to contrail cirrus (after correcting the scattering component of the long-wave forcing from the model30) amounts to 47.1 mW m−2 and short-wave radiative forcing to −9.6 mW m−2, resulting in a net radiative forcing of 37.5 mW m−2. This includes the effect of line-shaped contrails. Globally averaged contrail-cirrus optical depth is 0.05. Net radiative forcing of contrail cirrus (Fig. 3a) reaches values larger than 300 mW m−2 over the eastern US and central Europe. Over most of the US, Europe, over the North Atlantic flight corridor and also over parts of southeast Asia, net radiative forcing exceeds 100 mW m−2. Over much of the northern mid-latitudes contrail-cirrus radiative forcing exceeds 30 mW m−2. Maxima in radiative forcing are found in areas of maxima in contrail-cirrus coverage, but radiative forcing is enhanced in areas with large contrail-cirrus optical depth (Fig. 3b). This means that for a fixed contrail-cirrus coverage, radiative forcing is larger over southeast Asia than in the northern mid-latitudes and slightly larger over the eastern US than over central Europe or the North Atlantic flight corridor.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Another study that took advantage of the grounding gave striking evidence of what contrails can do. David Travis of the University of Wisconsin-Whitewater and two colleagues measured the difference, over those three contrail-free days, between the highest daytime temperature and the lowest nighttime temperature across the continental U.S. They compared those data with the average range in day-night temperatures for the period 1971-2000, again across the contiguous 48 states. Travis's team discovered that from roughly midday September 11 to midday September 14, the days had become warmer and the nights cooler, with the overall range greater by about two degrees Fahrenheit.
Return to Environment, Weather & Climate
Users browsing this forum: No registered users and 6 guests