mPing smartphone data collecting

Your reports will make weather forecasting better. The mPing Project crowdsources amateur reports of rain and snow so researchers can improve America’s Nexrad doppler radar system.

The National Oceanographic and Atmospheric Administration’s network of doppler weather radars, called Nexrad, detects precipitation and wind speed in clouds 230 kilometers away. Nexrad emits a pulse of microwave energy thirteen hundred times a second. Water droplets or ice crystals reflect part of that signal back towards the radar tower. The Nexrad system’s automated software analyzes the faint echoes to identify the kind of precipitation, its intensity, and the wind speeds. Nexrad lets meteorologists issue more accurate warnings of extreme weather than previous radar systems. That saves lives and protects the national economy.

But nothing is perfect. The reflected signal gets weaker the farther it travels. While Nexrad can tell the difference between most kinds of precipitation close to the tower, it gets fuzzier further away. By about 150 kilometers the system can only distinguish intense rain or snow. On top of that the radar can’t see weather close to the ground. That gap between the ground and the radar signal starts at the height of the radar tower and grows bigger as the beam travels. The gap is hundreds of meters high at the extreme end of the radar’s range. A lot can happen in that gap - especially during the winter. The radar may show snow, for example, but conditions just above ground-level could turn it into rain. Better algorithms that factor in wintertime conditions will give meteorologists more accurate data for their forecasts.

The mPing Project lets you help. Scientists at the University of Oklahoma, under a grant from Noaa, want to know what’s actually happening - the ground truth - beneath Nexrad’s radar pulse. That will let them create better algorithms, but the scientists can’t travel to every rain shower or snow flurry on their own. Fortunately there are a lot more amateurs than there are professionals. The mPing smartphone app - available for Android or for the iPhone - lets amateur weather-watchers everywhere report rain, snow, or other precipitation. The app packages the report with time and location data before uploading the report to the project’s servers. The combined reports of thousands of people produce the data the scientists need to refine Nexrad’s software. You can create animated loops of the weather data on the mPing site's display page.

A Noaa announcement of the mPing app reported that within its first few months amateurs submited more than 40,000 reports. The project’s researchers presented a paper to the American Meteorological Society’s 36th Conference on Radar Meteorology that reviews the technical limits of the Nexrad’s algorithms includes early analysis of the crowdsourced mPing data.