Sunday, December 14, 2014

Installing a new AWS

The weather has been quite variable in Antarctica over the last week or so. It may be a fine day at McMurdo, but more distant places could be cloud covered or winds could be enough to create a ground blizzard, thus landing an aircraft (e.g. the Twin Otter) is not possible. Within the ups and downs of constantly being on standby for flight, we have managed to get to a number of locations to work on some AWS stations. I thought I would post some pictures of a typical installation. This is the new Emma AWS station, which is located far south on the Ross Ice Shelf (84.00S, 174.36W).

Choose a location and assemble all the required equipment and instruments. Set up the high precision GPS (Global Positioning System) to get an exact location so we can find the AWS in future years.

Dig a 1m (3ft) pit for the tower and put the base plate in the bottom. We will put the bottom of the tower on this plywood base. Next, install three "Deadman" T-Anchors for guying out the tower once it has been raised.

A properly set tower with the main pit and anchor pits all filled in. The tower can now support the weight of a person climbing on it.

Installing the instruments, starting from the top down. The first item is the anemometer. We also have to determine which direction is true north and correctly align the wind direction detector.

Add all the additional instrument and the data logger box. Connect all the wiring from each instrument in the correct location.

Connect the power system (in the orange cases) and we have a completed installation.

Lastly, we need to check that data from the instruments is being correctly transmitted in real-time. This unit picks up the same signals that are transmitted to satellites (and ultimately back to the University of Wisconsin) and shows the codes on the small screen.