NASA's New Satellite Will Use Radar to Measure Global Rain and Snow
A new satellite launched by NASA at the end of February called Global Precipitation Measurement (GPM) will revolutionize the way meteorologists and other scientists view precipitation here on Earth. The satellite has the capability to take a high-resolution picture of all the precipitation occurring on earth — from rain to snow and everything in between — every two to three hours.
NASA's GPM page explains the mission's objective:
Global Precipitation Measurement (GPM) is an international satellite mission to provide next-generation observations of rain and snow worldwide every three hours. NASA and the Japanese Aerospace Exploration Agency (JAXA) will launch the GPM Core Observatory satellite carrying advanced instruments that will set a new standard for precipitation measurements from space. The data they provide will be used to unify precipitation measurements made by an international network of partner satellites to quantify when, where, and how much it rains or snows around the world.
GPM is preceded in spaceflight by its older satellite sibling known as the Tropical Rainfall Measuring Mission (TRMM). Launched in 1997, TRMM measures precipitation in the tropics to help researchers gain a better understanding of how "the distribution and variability of precipitation within the tropics as part of the water cycle in the current climate system," according to the mission's website.
A great example of the images captured by the older TRMM is seen in the powerful storm that came across the United States this past week. The satellite's microwave imager was able to capture clouds (especially the swirl west of California in the top frame), precipitation (seen in the second frame extending from AZ into CO), and snow cover (most of the yellow shading in the last frame) as the storm made its way east.
The TRMM is also able to see precipitation in much the same way that we're used to seeing with ground-based Doppler radars, as demonstrated by the satellite's observation of tornadic thunderstorms in the southeastern United States on February 21, 2014:
The mission behind GPM, which was launched on February 27, hopes to build upon the work and research that the TRMM satellite has provided the meteorological community for the past 17 years.
Engineers are currently testing out all of the GPM's equipment to make sure everything works as expected (it is, so far), and the satellite will likely begin transmitting regular data sometime this year.
