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MS036
Cold air drainage transect studies at the Andrews Experimental Forest, 2002 to Present

PRINCIPAL INVESTIGATOR: Christopher Daly
ORIGINATOR: Christopher Daly
OTHER RESEARCHER: Joseph I. Smith, John Moreau, Adam M Kennedy, Greg M Cohn
METHOD CONTACT: Joseph I. Smith
METADATA CREATION DATE:
20 Jul 2007
MOST RECENT METADATA REVIEW DATE:
18 Jul 2017
KEYWORDS:
Long-Term Ecological Research (LTER), meteorology, climatology, climate change, air temperature, topography, forest ecosystems
PURPOSE:
Temperature data are being collected to investigate the effects of elevation and local topographic position on the patterns of cold air drainage and pooling in the HJ Andrews Forest, and how they vary with synoptic weather patterns.
METHODS:
Experimental Design - MS036:
Description: Observed temperatures on “cold air” transects at 34 locations within the HJ Andrews Forest. The lower Lookout Creek transect (10 stations) is located just to the west of the concrete bridge, and intersects RS10. The upper Lookout Creek transect (11 stations) extends north from the north slope of Lookout Mountain, across Lookout Creek, and ends below the CENMET benchmark station. East of the upper transect, there is a short, 4-station transect across Cold Creek, a tributary of Lookout Creek. North of the upper transect, a 5-station cluster samples locations near a stream channel, above and below a spring. Single sensors are located downslope from the Roads End rain gauge near the southern border of the forest (high elevation, but locally low topographic position), and near the summit of Carpenter Mountain, on the northern border of the forest (high elevation, high topographic position, exposed to the free atmosphere). Two sensors will located temporarily in and above a sink northeast of the CENMET benchmark station. The upper and lower Lookout Creek transects were established in 2002, with others placed at later dates.
Field Methods - MS036:
Description: Data are sampled every 15 minutes with Hobo portable sensors mounted on rebar approximately 1.5 m above ground. Radiation shields are the “HJA short” type, which is made from PVC tubing, cut lengthwise and mounted above the sensor; sensors are open to the ground. Most sensors are located under dense forest canopy, with little solar radiation exposure. Many sensors also record illumination, which is useful in quantifying light exposure.
SITE DESCRIPTION:
Sites are selected along transects to represent elevational change moving in lateral directions away from a stream, or are clustered above or below a spring or depression. Two single points are selected at high elevations to represent one low and one high topographic position.
TAXONOMIC SYSTEM:
None
GEOGRAPHIC EXTENT:
HJ Andrews Experimental Forest
ELEVATION_MINIMUM (meters):
1616
ELEVATION_MAXIMUM (meters):
527
MEASUREMENT FREQUENCY:
15-min and daily
PROGRESS DESCRIPTION:
Active
UPDATE FREQUENCY DESCRIPTION:
annually
CURRENTNESS REFERENCE:
Ground condition