Radar satellites currently use IR measurements of cloud albedo to determine the water mass, density, and altitude of clouds, to understand precipitation for weather forecasts.
I am studying a proposition for a laser measurement apparatus intended to image 3D structure of whirls of cloud vapor in high resolutions, up to 30 kilometers awaym to capture clear point clouds of cumulonimbus.
It's to see into complex weather fronts with hot and cold air colliding in complex vortices, and to advance the science of meteorology.
If you can measure the speed of light in meters then you can measure the structure of a cloud in 3D...
If you shine a laser in every direction from the top of a mountain, in the form of small packets of photons, and measure the complex reaction of the light as it diffuses in the cloud and eventually reflects back to the base station (or to triangulation points), while giving the photons time to travel 30km into the sky prior to sending another burst, It should be possible to measure the density of the clouds in meter resolution at high frequencies.
High speed cameras should be able to capture the response of cloud traversing laser in the sky fast enough to plot thousands of points representing up to 10,000 photon traversals of the sky every second to a distance of 30 kilometers.
My grasp of water vapor interaction with different frequencies is very hazy, I am clearly falling into a technical pit that you will rapidly shovel back over me.
What wavelengths and physical interactions can travel through a cloud transparently enough to be measured into point clouds of sub meter resolution, what algorithms would be involved, and how to deal with the problem of diffraction by raindrops?