Measuring Groundwater from Satellites

The Utah Climate Center at the Utah State University publishes monthly climate notes. This month's issue has an article about measuring groundwater from satellites. "How in the world can you measure groundwater from a satellites", you might ask. I sure wondered how that is possible. You can read the article here. The basic idea is to have two satellites orbiting the earth fairly close together (about 120 miles apart from each other). As these two satellites communicate with each other, they measure the distance between each other which is related to the gravity of the earth. Despite what you learned in physics class, gravity is not constant. From small changes in the spacing of these two satellites a change in gravity can be calculated. Since all mass on earth contributes to the gravitational force, the absence or abundance of water underground will affect the gravity these satellites measure. Thus, groundwater levels can be measured by remote sensing. Kind of cool!  Again, you can read the entire article here: http://climate.usurf.usu.edu/news/011514Climate%20News%2063%20(Jan%2014).pdf

Also in this issue is a chart showing the current winter snow pack for various locations in Utah. The bottom line is this: WE NEED MORE SNOWSTORMS!!!