The Birds in the Cloud: How the University of Oklahoma Uses NEXRAD Data to Study Birds
The Next Generation Weather Radar Network (NEXRAD) is familiar to most of us as a backdrop for the weather report on the local TV news, but this radar array does more than track weather. During the spring and fall, NEXRAD detects vast “clouds” of migrating birds. This phenomenon is often an annoyance to meteorologists, but it turned out to be an opportunity for ornithologists at the University of Oklahoma (OU).
Dr. Eli Bridge who works at the Oklahoma Biological Survey at OU and his colleagues are using NEXRAD data to study birds and other flying animals. They can quantify nighttime migration of birds in the spring and fall by looking at radar reflectivity data where there is clear air. For one of their projects, they are trying to compile radar data to estimate the size of Purple Martin Roosts.
Purple Martins form large, dense aggregations during the late summer where there may be as many as 50,000 birds spending the night in two or three trees. When they leave these roosts at sunrise they make characteristic ring-shaped reflectivity patterns in scans from nearby radars. Eli is trying to use the radar data to develop an index of roost size (number of birds) and then compare roosts across years to see how things like drought and land use practices affect these regional bird populations.
In order to process radar data and work with it in various ways, they needed to find ways to get access to unfiltered, raw radar data. One option was to make requests for individual scans, which included making the request, waiting, receiving the response, and only getting a little bit of the data back at a time. A much better option would be to have an archive available to avoid making one-off requests.
“One of the biggest challenges in our work was simply obtaining large chunks of radar data to work with.” Eli said. “We had to make individual requests for lots of radar scans and then compile them on external hard drives or servers at OU (which costs us money). Having NEXRAD on AWS is a major help to us. I can download a radar scan in about 2-4 seconds. So there’s really no need for us to store raw data anymore.”
By looking at the entire NEXRAD archive (which extends back to the early 1990s), Eli and his team are able to study how birds are responding to droughts, climate change, environmental change, and seasonal queues.
“No way could we do this if we had to request data sets one by one. In short, we can work through large amounts of data quickly since NEXRAD is on AWS. Now the door is open to us and we have to figure out how to process all of it,” Eli said.
Now that all of the NEXRAD data is available, the heavy lifting aspect has shifted. You can start thinking much bigger. Having something like a continental-scale mosaic of all the NEXRAD radar scans over a 10-minute period available as raw data (not just a report or an image) would be the evolution of this kind of big data. This is something you can only do because it’s in the cloud and it is widely shared.
Learn more about NEXRAD on AWS in this blog post.