Any satellite in a low Earth orbit can make observations of the Earth from fairly low down, and it can observe the clouds and weather patterns on Earth from the outside. Such a satellite is also particularly useful for atmospheric studies because it can study the atmosphere from up close. A satellite in low orbit can also be looking into deep space, like the Hubble Space Telescope.
A satellite in low altitude orbit flies within the Earth's atmosphere, but at its highest layer where there are almost no atmospheric gases to cause drag and slow the satellite down. Because it does not have to go as high up, the satellite also requires less energy to launch into space. The rocket launching the satellite will thus need less fuel.