Nome Creek

Created: 2014-01-31 13:17:06
Modified: 2014-01-31 13:18:28

DESCRIPTION OF AREA CONTAINING SITE:

The Nome Creek site is located within the White Mountains Recreation Area in Alaska. The 50m2 grid is in a moderately well drained area of rolling hills & creeks that was once predominately a gold mining area. The grid site area is open, but the surrounding land is populated with spruce (predominant) and birch trees. The land is hummocky. The 50mx50m grid, established in 2010, is marked with survey stakes along the West and East sides in 5-meter intervals. Shorter stakes were used per BLM request. The grid center (N65.37, W147.06) 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 in the second year of a cooperative agreement with the Yukon River Inter-Tribal Watershed Council and the U.S. Geological Survey. The Burea of Land Management gave Land permission.

SAMPLING DESIGN AND METHOD:

The Nome Creek site was chosen to increase the range of distribution of Active Layer Network sites.

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. 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 1m 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 58cm. 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 56cm and 46cm (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 533m, recorded at grid center.