I wanted to know what the scientists had to say about the increased contrails (white lines in our sky that spread out, turning our blue skies white), so I researched, found the most amazing research, and wrote to the University of Utah Meteorology Department hoping to address this issue in our inversion/pollution prone area that is covered with contrails almost daily.
The NASA affiliated research I found proved the following:
1. Contrails are increasing in numbers, doubling by 2015 and quadrupling by 2050 if nothing is done.
2. Contrails do affect our weather
3. A contrail-sensitive area can be predicted between 1-6 hours in advance
4. Because contrails can be predicted, contrails can also be reduced and/or increased
Below the orange squiggly is the letter I sent to the U of Utah on February 25, 2013. It was one of those days that started out with bright blue skies, not a cloud in sight until the contrails began and didn't stop until the sky turned white. Here's a 2/25 noon pic of contrails above SLC valley
Sadly, the links to a couple of the research papers I read no longer work. This is the message that now appears:
The NASA technical reports server will be unavailable for public accessGranted, the research papers included long, complicated mathematical equations that could teach other countries about this science and I guess that is proprietory information?
while the agency conducts a review of the site's content to ensure that it
does not contain technical information that is subject to U.S. export control laws
and regulations and that the appropriate reviews were performed.
The site will return to service when the review is complete.
We apologize for any inconvenience this may cause.
Fortunately, before the articles were taken down by NASA, I did copy and paste the information written that substantiates the items listed above.
I will let you be the judge.
Here's the letter:
Good morning, Professor
I have been studying/tracking local contrails as a non-scientific observer for a couple of years and found research that verifies some of my conclusions. I wanted to share both with you for your opinions.
I am writing today because of the high quantity of contrails I am observing this morning, with hopes that you might have a chance to observe them as well.
Of particular interest to me is what appears to be a trend. Specifically, in front of a system the contrails seem to increase dramatically. I understand the conglomerate of atmospheric conditions that might facilitate these. However, as it is proven that heavy contrails can affect weather, I wonder if these are planned and, if not, if we might provide some input to the industry to plan flights in order to reduce them over our populated areas.
I found this research paper that clearly states that the altitude of flights can directly determine the creation of contrails. The paper also states that creation of contrails will double between the years of 1992 and 2015 and quadruple by 2050.
Evaluation of Contrail Reduction Strategies Based on Aircraft Flight Distances
""This paper evaluates a set of contrail reduction strategies based on the flight range of aircraft as contrail reduction strategies have different impacts on aircraft depending on how they plan to fly...The paper concludes that contrails creation can be reduced by 75% by simply adjusting flight altitudes.
The strategy for reducing the persistent contrail formation is to minimize the contrail frequency index by altering the aircraft’s cruising altitude....
The global mean contrail coverage in 1992 was estimated to double by 2015, and quadruple by 2050 due to predicted increase in air traffic.3
Studies suggest that the environmental impact from persistent contrails are estimated to range from three to four times, to ten times larger than from aviation-induced emissions. To address minimizing environmental impacts due to contrails, methods to reduce aircraft induced persistent contrails have been proposed.""
The percentages of the reductions are similar with different α values for long- distance flights. For the top three contrail days in April, 2010, the contrail frequency index per 1,000 miles for medium-range, long-range, and transcontinental flights can be reduced by an average of 75%.The authors of the paper above have also written the following paper, which you CAN read.
A class of strategies has been proposed to reduce contrail formation in the United States airspace. A 3D grid based on weather data is built and the cruising altitude level of aircraft is adjusted to avoid the persistent contrail potential area with the consideration to fuel-efficiency.
Also, in this paper below, it states that the production of contrails can even be predicted ahead of time. If so, isn't it possible that contrail production over the Wasatch Front can be reduced if meteorologists and the aviation industry could work in concert with each other.
Prediction and Use of Contrail Frequency Index for Contrail Reduction Strategies
"The objective of this paper is to derive a class of indices that can identify and predict, up to six hours in advance, regions of airspace with high potential for contrail formation.In this Prediction paper, Salt Lake is shown as one of seven areas that "need a reduction strategy" Again, inversions in SLC create dangerously toxic air that is harming residents.
""Traffic and weather forecasts were used to generate the predicted contrail frequency index. The indices are used to identify air traffic control centers and altitudes with high contrail formation activities over the next one to six hours."
This paper described a methodology to predict contrail frequency index for contrail reduction. A class of predicted indices that reflects the severity of airspace contrail formation frequency was derived. The indices consist of weather forecast and actual and historical air traffic data. The results show that the predicted indices are affected more by changing atmospheric conditions than by small daily variations of traffic. For the data tested, the one-hour predicted contrail index is highly correlated with the actual index, resulting in an average correlation coefficient of 0.85 and is lower with longer prediction time. The average correlation coefficient between the actual index and the two-hour, three-hour, and six-hour predicted index are 0.72, 0.64, and 0.52, respectively. In terms of developing strategies for contrail reduction, there is a 83.47% success rate to identify centers with contrail frequency index greater than a threshold, 69.24% using two-hour index, 58.31% using three-hour index, and 38.92% using six-hour index. The method of using predicted contrail frequency index for contrail reduction shows promise but requires detailed future evaluation in a fast-time traffic flow management simulation environment."
For implementing a contrail reduction strategy, the centers with high contrail frequency indices need to be identified. As an example, the contrail reduction strategy may be enabled when the centers have indices higher than 100. This would affect seven centers including Los Angeles Center (ZLA), Salt Lake City Center (ZLC), Albuquerque Center (ZAB), Dallas/Fort Worth Center (ZFW), Houston Center (ZHU), Jacksonville Center (ZJX), and Miami Center (ZMA). All of the one-hour, two-hour, and three-hour prediction indices are able to correctly identify the centers that need a reduction strategy with the exception that the three- hour predicted index fails to identify ZHU.What is really interesting is the ability to very accurately predict when contrails will be created, from the Contrail Prediction paper cited above:
The evidence indicates that a decrease in contrails is possible by simply adjusting the altitude of medium range flights, which my analysis* indicates are the flights creating our contrails.
A few of the scientists that wrote the above papers agree with me. Specifically, in this paper:
Aircraft Trajectory Optimization and Contrails Avoidance in the Presence of Winds
""There are indications that persistent contrails can lead to adverse climate change, although the complete effect on climate forcing is still uncertain.Lastly, I have watched a heavy day of contrails spread out and completely cover an AM blue sky by mid afternoon. Admittedly, I lack a scientific background; however, I am curious about the effects this contrail sky cover might have on our inversion problem (Salt Lake/Utah counties have one of the highest particulate pollution problems in the country).
A flight trajectory optimization algorithm with fuel and contrails models, which develops alternative flight paths, provides policy makers the necessary data to make tradeoffs between persistent contrails mitigation and aircraft fuel consumption.
This study develops an algorithm that calculates wind-optimal trajectories for cruising aircraft while avoiding the regions of airspace prone to persistent contrails formation."" (emphasis mine)
Based on the above research and the scientific clout of the U of U's meteorology professionals, is it possible that the airlines could be asked/required to, at the very least, adjust their flight patterns and/or altitudes to eliminate contrail creation when we are in the throes of our unhealthy air quality periods?
Thank you for your consideration and time addressing my questions.
*My Tracking the Contrails technique using FlightAware website
I have been using FlightAware to find out what airline/plane is creating contrails in our area.
Specifically, I open FlightAware in two screens which I put side by side on my iMac.
Both are opened to the SLC airport link. When I observe a heavy contrail, I go to FlightAware on the left screen, find the plane ID and enter it into the Flight Number box on my right screen. The planes that create the contrails are always the green planes. The torquiose planes are the flights arriving/departing from the SLC airport and fly low enough to avoid creating contrails.
Steps to observe and identify flights creating contrails for Salt Lake area (use your own airport for your area):
1. Open FlightAware SLC. Link http://flightaware.com/...
2. Click on the 4 arrows to bring up larger view of KSLC air space activity. This will bring up a large view. Increase screen size to fill left half of computer screen
3. Open new window. Then open FlightAware SLC. Link http://flightaware.com/...
4. Move to right half of computer screen, making sure that the Flight/Tail# identification Box is visible
5. When a contrail is observed, find the plane (again always green colored). If the Flight/Tail# isn't displayed, hovering the cursor over the green plane will usually display the ID. If that doesn't work, click on the plane. This will create a view of just the specific plane's history. You will then have to reopen KSLC for viewing entire airspace in the left hand screen.
6. Enter the Flight/Tail# info into the Flight/Tail# box on the right screen Flight/Aware and observe the flight history, which includes altitude.
7. I also use this webcam which often shows the contrails I track. It would be very helpful if the archival records included recent items.
Salt Lake Valley Hazecam (Full Size Image at Bottom of Page) @ http://home.comcast.net/...
I have observed many days over the past couple of years.
I have observed that many airlines create these heavy contrails; however, only when flying at the altitudes conducive to contrail creation, explained by the research above.
I have also observed that the flight paths of many of the contrail creators seem to illogically fly directly over our most polluted areas en route, literally going out of their way to do so.
Here's a good example. Airplane WJA1486. This plane flight frequently, if not bi-daily, creates a contrail over our valley. If you click on each day of WJA1486's flights beneath the map, you will see a consistent pattern of flying over our most polluted air spaces.
At 11:50 AM (February 25, 2013) this flight, WJA1486, created a heavy contrail. It didn't have to fly over our area if a direct path had been chosen. Why did it? http://flightaware.com/...
I also wonder if Utah's many cloud seeding, ground-based generators help set up the contrail conditions?
Lastly, I wonder if the atmospheric conditions being created with contrails and intentional weather modification technology west of the Rockies could, in any way, contribute to setting up areas to the east of the Rockies for more intense weather events?
I understand that much more measuring and detail recording would be required to make a case for asking airlines to be more considerate of our sensitive area; however, I believe the above is an easy technique to begin do so.
I think it is possible, over time, to prove that these contrails do, in fact, impact our local weather and air pollution and, more importantly, can be avoided with the cooperation of the airlines.
I would like to volunteer to help if you see any merit in doing so to either help prevent some of our country's extreme weather events and/or help reduce Utah's horrible air pollution.
Again, thank you if you have read this far. Today's whitening sky is definitely the result of heavy contrails. Lastly, could these have an effect on The field campaign for the Persistent Cold-Air Pool Study?
END OF LETTER
I didn't get a response, sadly. And, hopefully the NASA affiliated research papers I found and read before writing to the U of U Professor will return so you, too, can read them in their entirely.
Contrails can be predicted and reduced by changing flight altitude and/or avoiding, when possible, areas conducive to contrail creation. Conversely, contrails can predicted and increased if the atmosphere is conducive.
A heavy contrail presence, or lack thereof, can affect weather although online research provides conflicting outcomes.
From New Scientist
From the Christian Science Monitor
Here's a visual demonstration of contrails becoming cirrus clouds from NASA
For those wishing to do more research, the authors of the papers cited above are
Neil Y. Chen and Banavar Sridhar
NASA Ames Research Center, Moffett Field, CA 94035-1000
Hok K. Ng ‡ University of California, Santa Cruz, Moffett Field, CA 94035-1000
Another paper by the above authors:
Contrails create cirrus clouds. Cirrus clouds affect weather. This is for the scientists among us: Cirrus Clouds have a great influence on weather. Scientific Paper