Water Vapor Layer
Have you come across water vapor data for a layer? I've only ever seen that as an image, like https://www.weather.gov/satellite#wvGOESe
Weather satellites provide images of Earth mainly in 3 channels
(visible, infrared and water vapour).
Water vapour images show the air streams and water vapour content
in the upper and middle levels of the troposphere.
If you want to see the humidity at different layers in the atmosphere,
you can use “humidity” and height slider.
e.g. here you see humidity over USA at 10,000ft.