Lidar accelerates hurricane recovery in the Carolinas

Louise Smyth

Hurricane Florence's slow trot over North and South Carolina in September led to inundating rain, record storm surges and another major disaster for the Federal Emergency Management Agency (FEMA) to contend with. Facing damage over hundreds of square miles, FEMA again called upon MIT Lincoln Laboratory to use their state-of-the-art lidar system to image the destruction in the region.

Installed onto an airplane and flown nightly over a disaster site, lidar (which stands for light detection and ranging) sends out pulses of laser light that bounce off the land and structures below and are collected again by the instrument. The timing of each light pulse's return to the instrument is used to build what researchers call a point-cloud map, a high-resolution 3D model of the scanned area that depicts the heights of structures and landscape features. Laboratory analysts can then process this point-cloud data to glean information that helps FEMA focus their recovery efforts — for example, by estimating the number of collapsed houses in an area, the volume of debris piles and the reach of flood waters.

Yet quickly sending the nearly two terabytes of data from a single night's sortie to the Laboratory for processing is a challenge. After a storm, local internet connections may be gone. When the Laboratory used this same lidar platform after Hurricane Maria in Puerto Rico, downed networks meant having to physically ship a hard drive back to Massachusetts — a more than two day delay in getting the data into analysts' hands. When the team started the campaign in the Carolinas in mid-September, they faced the same obstacle.

This time, the obstacle was hurdled thanks to MCNC. The nonprofit organisation formerly known as the Microelectronics Centre of North Carolina is based in Research Triangle Park near Durham, North Carolina, which was not directly affected by Hurricane Florence. MCNC gave the Laboratory free access to its North Carolina Research and Education Network (NCREN).

"Our state was hit hard by Hurricane Florence," said Tommy Jacobson, MCNC's chief operating officer and vice president. "For MCNC's leadership, it was a quick and easy decision to enable MIT, who was in the state to assist FEMA, with access to our network resources to help however we could in making sure relief got to those that needed it."

NCREN is North Carolina's broadband backbone, connecting more than 750 institutions including all public school districts in the state, universities and colleges, public safety locations and other community anchor institutions. Access for the Laboratory meant rack space for equipment inside the MCNC data centre. From there, MCNC provisioned a 10 gigabit IP connection from the NCREN to Internet2, an ultrafast, advanced network that connects research centres around the world. This connection gave the team the ability to upload large volumes of data daily from their equipment inside the data centre back to a computing centre on MIT campus that is also connected to Internet2. From there, another 10-gigabit connection bounced the data from campus to the Lincoln Laboratory Supercomputing Center in Holyoke, where the data were processed.

"The 10-gig uplink from MCNC allowed us to transmit the data at such a higher speed that some of our uploads were done in about six to seven hours," said Daniel Ribeirinha-Braga, a member of the Laboratory's data management team in this hurricane effort. "Keep in mind that this is lidar data, which we get about 1.5 to 1.9 terabytes a night of, that needs to be copied to multiple places, such as other hard drives, organised to a single SSD [solid-state drive], and then uploaded to the Laboratory from MCNC."