UAV Antarctic moss bed case study

 

This is a collaborative project with Prof. Sharon Robinson from the University of Wollongong and Dr Dana Bergstrom from the Australian Antarctic Division. The project is supported by an Australian Antarctic Science Grant: AAS3130.

Polar regions are experiencing rapid and severe climatic shifts with major changes in temperature, wind speed and UV-B radiation already observed in Antarctica. Since vegetation is isolated to the coastal fringe and climatic records only extend back 50 years, with limited spatial resolution, we urgently need new proxies to determine if coastal climate has changed over the past century. In a manner similar to trees, old growth mosses also preserve a climate record along their shoots. Our ability to accurately date these mosses and map their extent in sufficient spatial detail means that, for the first time, mosses can be used as sentinels to provide crucial information on how the Antarctic coastal climate has changed over past centuries and how biota has responded to these changes.

The spatial scale of the moss beds (tens of m2) makes satellite imagery (even very high resolution imagery of 0.5 m) unsuitable for mapping their extent in sufficient detail. Due to logistical constraints aerial photography is impractical. Recent developments in the use of unmanned aerial vehicles (UAVs) for remote sensing applications provide exciting new opportunities for ultra-high resolution mapping and monitoring of the environment. In this study, we developed a UAV consisting of a remote controlled helicopter carrying three different cameras: visible colour, near-infrared, and thermal infrared for cost-effective, efficient, and ultra-high resolution mapping of terrestrial vegetation in the Windmill Islands, Antarctica. These three sensors allow us to map different physical characteristics of the moss beds at resolutions of several centimetres. 

Healthy moss bed in the Antarctic Special Protected Area (ASPA) 135 close to Casey.

Close-up of a healthy moss bed, the "miniature old-growth forests of Antarctica"

 

 

Small UAV based on a model remote controlled helicopter and custom-built components for aerial photography.


View a YouTube video of a UAV flight over the ASPA135 moss bed!

Flying the UAV a Robinson Ridge for moss bed photography.

 

The UAV flight path for the flight shown above in Google Earth. Click on the image to see the flight path in Google Earth!

A georeferenced moss bed photograph taken from the UAV with quadrat locations shown overlaid on top.

A thermal image of a moss bed.

A UAV photo mosaic draped over a high-resolution DEM to create a 3D terrain view.

Topographic Wetness Index derived from the DEM for the same area as the figure above.

Healthy moss

A small depression showing the effect of micro-topography and water availability on moss health with green healthy moss in the depression, and drier and dead moss further up the slope where water availability is low.

Exciting new image processing techniques allow us to extract incredibly detailed 3D point clouds from overlapping UAV photography similar to a laser scan. The point spacing in this screenshot is approximately 1 cm (10,000 points per m2) with individual rocks covered in hundreds of points.

 

From the 3D point cloud above a 1 cm resolution digital elevation model (DEM) can be derived. This allows us to accurately model the effects of the terrain on water availability, solar radiation, and wind.

UAV research in Antarctica is hard work!

 

 

 

 

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