LiDAR at Mt. Erebus
Today we said goodbye to Kevin Mickus (gravity man) and Jed Freschette (LiDAR man), two of our awesome team doing awesome science at Mt. Erebus. In my previous post I described Kevin's gravity work, and here I'll describe Jed's LiDAR work, which ties into my ground penetrating radar surveys.
LiDAR stands for Light Detection And Ranging, meaning it detects light (laser light, specifically) and also computes the distance the light has traveled. A laser is shined at an object, which reflects and back-scatters that light, which is then received and analyzed by the LiDAR unit. Lasers are used because they produce a very narrow, intense beam of light, from which a reflected signal can be accurately associated with a specific point on the object of interest. Therefore, LiDAR can obtain very fine resolution.
There are several types of LiDAR with different applications:
- terrestrial (urban, forrestry, etc)
- airborne (down-looking from airplanes, helicopters,
- space-borne - nir
- atmospheric (maps column of air space above) - green
Here on Mt. Erebus, scientists Jed Freschette and Drea Killingsworth are using LiDAR to map the accessible rooms of ice caves formed by the volcano. This not only gives location, and extent of the caves, but an idea of volume and structure as well.
|LiDAR unit upon a tripod, with a target and tripod in the background. Each scan round must have a GPS location, or be co-located to a dataset with location information.|
|LiDAR in the process of scanning the ice cave with green laser. The swath of light is made by a rapidly scanning laser, and moves through a 270 degree field-of-view.|