04-05-2017, 12:38 PM
The graph of vapor pressure of water isn't quite a hockey stick, but it is close. It's almost a parabola.
![[Image: image_40.scale.large.jpg]](https://www.acs.org/content/acs/en/climatescience/atmosphericwarming/climatsensitivity/jcr:content/articleContent/columnbootstrap_3/column0/image_40.scale.large.jpg)
Degrees Kelvin are on the same scale as degrees Celsius. Subtract 273.15 from the Kelvin measurement, whose "zero" is the absolute zero of physics (nothing can be cooled below that point) and is more useful for physical applications including meteorology, and one gets the Celsius temperature, whose zero is at the freezing point of water and whose 100 is at the boiling point of water, temperatures with which we are all familiar.
Air can hold about twice as much water vapor at 10° C (50° F) than at 0° C (32° F), about twice as much at 20° C (68° F) than at 10° C (50° F), about twice as much at 20° C (68° F) than at 10° C (50° F), about twice as much at 30° C (84° F) than at 20° C (68° F), and about twice as much at 40° C (102° F) than at 30° C (84° F).
To relate the temperatures, 0° C (32° F) is the freezing point of water, or about the temperature that you have in iced tea. 10° C (50° F) is unpleasantly chilly, but not too bad with a good sweater. 20° C (68° F) is borderline for bare flesh. That's a typical high temperature for San Francisco from May to October. 30° C (86° F) is about when 'warm' becomes unpleasantly hot, depending on wind speed and humidity. 40° C (104° F) is tolerable with low humidity so long as you drink plenty of water (not sugary or alcoholic drinks... iced tea is OK largely for the cooling effect), but generally unpleasant. 50° C (122° F) is dangerously hot, especially with high humidity as around the Persian-Arabian Gulf. Above that? At 45° C (113° F), the highest temperature I ever felt -- Dallas in 1980 -- things were nasty. I wore winter clothes as a defense against the heat.
During the last glacial maximum the ice sheets reached as far south as southern Ireland, a place that is now borderline -- subtropical -- and Louisville, Kentucky. Southern Ireland has a few palm trees, and Louisville gets unpleasantly hot in contemporary summers. You would have been lucky to find a lichen or moss near the southern end of the peak of glaciation.
Degrees Kelvin are on the same scale as degrees Celsius. Subtract 273.15 from the Kelvin measurement, whose "zero" is the absolute zero of physics (nothing can be cooled below that point) and is more useful for physical applications including meteorology, and one gets the Celsius temperature, whose zero is at the freezing point of water and whose 100 is at the boiling point of water, temperatures with which we are all familiar.
Air can hold about twice as much water vapor at 10° C (50° F) than at 0° C (32° F), about twice as much at 20° C (68° F) than at 10° C (50° F), about twice as much at 20° C (68° F) than at 10° C (50° F), about twice as much at 30° C (84° F) than at 20° C (68° F), and about twice as much at 40° C (102° F) than at 30° C (84° F).
To relate the temperatures, 0° C (32° F) is the freezing point of water, or about the temperature that you have in iced tea. 10° C (50° F) is unpleasantly chilly, but not too bad with a good sweater. 20° C (68° F) is borderline for bare flesh. That's a typical high temperature for San Francisco from May to October. 30° C (86° F) is about when 'warm' becomes unpleasantly hot, depending on wind speed and humidity. 40° C (104° F) is tolerable with low humidity so long as you drink plenty of water (not sugary or alcoholic drinks... iced tea is OK largely for the cooling effect), but generally unpleasant. 50° C (122° F) is dangerously hot, especially with high humidity as around the Persian-Arabian Gulf. Above that? At 45° C (113° F), the highest temperature I ever felt -- Dallas in 1980 -- things were nasty. I wore winter clothes as a defense against the heat.
During the last glacial maximum the ice sheets reached as far south as southern Ireland, a place that is now borderline -- subtropical -- and Louisville, Kentucky. Southern Ireland has a few palm trees, and Louisville gets unpleasantly hot in contemporary summers. You would have been lucky to find a lichen or moss near the southern end of the peak of glaciation.
The ideal subject of totalitarian rule is not the convinced Nazi or the dedicated Communist but instead the people for whom the distinction between fact and fiction, true and false, no longer exists -- Hannah Arendt.