Extinct but not forgotten Staff Member
I have not said one thing about possible atmospheric changes increasing contrail formation . . . I am not asking if more traffic increases RH or nuclei or if climate change is increasing RH at higher altitudes and thus increasing persistent contrail formation . . . I am asking the following . . .I don't think there are significant atmospheric changes for contrail formation or persistence.
Temperature is up by about 0.8°C, mostly in recent decades. I don't think this means much in terms of the height of the -40°C isotherm.
As far as I know, there is no change in the RH (not the same as water vapor content).
The question involves memory, storage efficiency, recollection accuracy, conscious interest, and other qualitative influences.
When you started this line of questioning, you didn't mention we were dealing with immeasurable organic factors like memory.
As Mick says, the reasons are about changes in the aviation industry. Memory for this type of thing is very unreliable, as we have seen. For instance, the first persistent contrail I recall noticing was in about 2002. I started in meteorology in 1977. You would think that I would recall seeing one before 2002, but I don't. No shame; not unprofessional; poor memory. Pfft. There is plenty of reliable actual documentation to rely on, though.
1) Do you or do you not think the fact more aircraft are capable of flying above 28,000 feet has increased persistent contrails formation over previous decades primarily because they are transversing colder temperatures than they would at lower cruising altitudes ?
2) or do you think the greater number of contrails is due primarily to the faulty memory of people and that there are simply more aircraft flying at all altitudes ?