Weather forecasting is a notoriously inexact science. According to San Francisco-based tech startup Spire, this is partially because there are currently less than 20 satellites responsible for gathering all of the world's weather data – what's more, some of the older ones are using outdated technology. Spire's solution? Establish a linked network of over 100 shoebox-sized CubeSats, that will use GPS technology to gather 100 times the amount of weather data than is currently possible. The first 20 of those satellites are scheduled to launch later this year.
Each of the CubeSats will reportedly cost "a fraction" of a typical full-sized weather satellite, yet offer considerably more computing power. Additionally, their software will be upgraded every two years, via radio transmissions from the ground.
In order to gather their weather data, the CubeSats will utilize a technology known as GPS Radio Occultation. This involves receiving and analyzing signals from existing GPS satellites.
As one of those signals travels from a GPS satellite to a low-orbit Spire satellite, it will pass through the Earth's atmosphere. Keep in mind that the curve of the planet will cause the atmosphere to likewise curve up between the two spacecraft, provided they're far enough apart. By assessing how that signal is refracted by the atmosphere, it will be possible to calculate factors such as temperature, pressure, and humidity – with more accuracy and detail than is possible using other methods.
That data will then be transmitted down to ground stations. Even with just the first 20 satellites in place, a claimed 10,000 data readings will be made per day. By contrast, Spire states that the world's present collection of weather satellites produce only about 2,000 combined readings per day, and they don't provide sufficiently frequent readings for approximately three quarters of the planet – this mainly includes areas such as oceans and other remote regions.
If everything goes according to plan, all 100 CubeSats should be in orbit by the end of 2017. The network should then thoroughly cover the entire world, oceans and all.