NASA and the US Air Force make it clear in their own publications that conditions of high relativity humidity are required at flight level before a jet aircraft is capable of producing a “persistent contrail”.
Since there are only rare exceptions to this fundamental rule of water vapor contrail formation, it’s a simple task to distinguish between normal persistent contrails and persistent contrails containing undisclosed, chemical aerosol pollutants.
NASA: “Persistent (non-spreading) contrails look like long white lines that remain visible after the airplane has disappeared. This shows that the air where the airplane is flying is quite humid, and there is a large amount of water vapor available to form a contrail.”
USAF: “The rate at which contrails dissipate is entirely dependent upon weather conditions and altitude. If the atmosphere is near (water vapor) saturation, the contrail may exist for some time. Conversely, if the atmosphere is dry, the contrail will dissipate quickly.“ Contrail Facts, Pg. 13.
Now let’s examine the case of an Air France, Airbus A-380 – registration number (F-HPJA) – where the timeline and conditions are well documented in order to effectively demonstrate how persistent contrails can be far more than citizens have been led to believe.
A telephoto image clearly showing the registration number (F-HPJA) of the Airbus A-380 was chosen for this example. A search at AeroTransport Databank succeeded in retrieving details and more images of the aircraft including the date, precise location and altitude. (38,000 ft.)
An Airliners.net member posted a photo of the A-380 captured over Kemble air field, UK on Aug 26, 2012. Radiosonde data from 6 stations (data below) on that date, confirm Temp. = < 39 deg C. and relative humidity did not exceed 11% (eleven percent) at 38,000 ft. in any sample. This finding is science-based evidence that emissions from this commercial, passenger aircraft are based on chemical aerosols that have nothing to do with typical formation of normal, water vapor contrails.
Compelling evidence shows radiosonde data from 6 stations adjacent to Kemble air field report Temp = <39 C. and relative humidity at flight level of 38,000 ft. on that day was VERY LOW and did not exceed eleven percent (11.0 %) !
8/26/2012 Weathersonde Data
03882 Herstmonceux Observations at 00Z 26 Aug 2012 RH = 10% at 38,000 Ft./11,500 Meters
03354 Nottingham Observations at 00Z 26 Aug 2012 RH = 4% at 38,000 Ft./11,500 Meters
03238 Albermarle Observations at 00Z 26 Aug 2012 RH = 4% at 38,000 Ft./11,500 Meters
03808 Camborne Observations at 00Z 26 Aug 2012 RH = 2% at 38,000 Ft./11,500 Meters
03918 Castor Bay Observations at 00Z 26 Aug 2012 RH = 2% at 38,000 Ft./11,500 Meters
10113 Norderney Observations at 00Z 26 Aug 2012 RH = 2% at 38,000 Ft./11,500 Meters
Minnis Chart reveals probability of contrail and Cirrus formation at flight level and T <39 deg C. and below 60% Relative Humidity is extremely low.