Ruby

Created: 2014-01-31 13:27:36
Modified: 2014-01-31 13:28:48

DESCRIPTION OF AREA CONTAINING SITE:

Ruby is located along the South bank of the Yukon River in the Yukon-Koyukuk region of Alaska. The 50mx50m grid site is located on the North Side of Alfred Gurtler Street, just past Mosquito Street and behind the old lift station. The area around the lift station was probably plowed over with heavy machinery at some point and gravel was put down. A portion of the grid was “disturbed” and unable to be measured due to this disturbance. We used the area anyway due to challenges with land permission and time. The area is thickly forested with black spruce and high tussocks. The grid, established in 2010, is marked at 5-meter intervals with surveyor stakes along the West and East sides of the grid. The grid center (N64.73 W155.48) contains continuous soil temperature & soil moisture sensors at “above permafrost” & “just below surface” levels. An air temperature sensor is installed on a spruce tree near grid center. All sensors collect and store data on a 30-minute continuous cycle. The grid was established in 2010, with assistance from Ruby Tribal Council, in the second year of a cooperative agreement with the Yukon River Inter-Tribal Watershed Council and the U.S. Geological

SAMPLING DESIGN AND METHOD:

The Ruby site was chosen to increase the range of distribution of Active Layer Network sites. Assistance from the Ruby Tribal Council in land permission and location was given.

The grid consists of 2 parallel lines of 10 survey stakes at 5-meter intervals, creating a 50mx50m square grid with a maximum of 100 data points. A compass was used to orientate the grid to a square. Active Layer measurements were taken manually every 5m and recorded on a fieldsheet. The measurements were taken at the lowest surface level within about 0.3m of the designated point, to minimize the questionable influence of tussocks on the AL measurement. The "surface level" was determined to be the top of the low-lying vegetation (i.e. moss, lichen, low-bush berries). Thaw measurements greater than 1.3m were noted, but not used in calculations, as of 2009. [CALM protocol suggests a grid size of 100mx100m, however a 50m2 grid was deemed acceptable due to difficult terrain and length of time for installation (personal communication Dr. V.Romanovsky).]

The soil climate station was established in early September 2010 and is located near grid center. The station monitors air temperature, soil temperature & soil moisture. The HOBO micro station was installed at the grid center. A ~30cm4 hole was dug down to the permafrost layer at 40cm. One set of soil moisture and soil temperature sensors were placed just above the permafrost layer and one set just below surface level. Soil samples were cut from 37cm and 25cm (cubes) to be analyzed for soil moisture content. The HOBO pro v2 temp/ext temp sensor was installed, recording air temperature, near the grid center about one meter off the ground surface. The Hobo data logger is set to store data on 30min intervals for up to 428 days.

GPS points were taken at the four corners of the grid, as well as the center point where the sensors were located. Site elevation is 110m, recorded at grid center.