nkline - 6/6/2023 17:49

If you watch the maps in winter it doesn’t seem to pick up snow as moisture until it melts. From their website, “satellites, which detect small changes in the Earth's gravity field caused by the redistribution of water on and beneath the land surface. The paired satellites travel about 137 miles (220 km) apart at an altitude of 300 miles (485 km) and record small changes in the distance separating them as they encounter variations in the Earth's gravitational field.”

My thoughts are the sensors have to do with the polarity of water, when water is snow the polarity probably does not change the gravitational field because the charges lie in multiple directions. You can bend a stream of water with a magnet because of the alignment of charges. I may be wrong, but that seems like the simple explanation to me.