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MS007
Snow depth and snow water equivalent measurements along a road course and historic snow course in the Andrews Experimental Forest, 1978 to present

PRINCIPAL INVESTIGATOR: Mark D Schulze
ORIGINATOR: Alfred B. Levno
OTHER RESEARCHER: Christopher Daly, Christopher J. Still
DATA SET CONTACT PERSON: Donald L. Henshaw
ABSTRACTOR: Donald L. Henshaw
TOOL CONTACT: John Moreau
METHOD CONTACT: Greg Downing
FORMER INVESTIGATOR: Frederick A. Bierlmaier, Anne W. Nolin, Adam B. Mazurkiewicz
METADATA CREATION DATE:
12 Nov 2004
MOST RECENT METADATA REVIEW DATE:
6 Jul 2017
KEYWORDS:
Disturbance, Primary production, hydrology, climatology, microclimate, precipitation, snow, snow water equivalence, reference stands, primary production, disturbance, modeling, roads, clearcuts, old growth forests
PURPOSE:
Provide a baseline for characterizing distribution and variation in snow depth, moisture, and duration in the Andrews Forest for climatological and hydrological modelling, and examine differences in snow accumulation in clearcut and adjacent closed forest stand microclimates.
METHODS:
Experimental Design - MS007 :
Description: Snow stakes are established starting at the Primary Met Station (430 meters elevation) and at approximately 150 meter elevation increments along Andrews Forest roads. Sites are established in open canopy/closed forest pairs, with stakes at each paired location as close together as possible. One stake is placed in a forest opening (no canopy interference with snow accumulation) and one stake is placed in an older forest (preferably an old growth stand). Snow water equivalent measurements (snow moisture content) are collected once or twice per year with 3 snow cores taken in the vicinity of the snow stake and averaged. The historic Reference Stand snow course included paired open and closed canopy locations within the Andrews Reference Stands and Wildcat RNA thermograph sites.
Field Methods - MS007: Road snow course :
Description:

A snow stake is established at each site with a metal fence post driven into the ground to support a 2" PVC pipe that slides over the post. Survey rod decals are placed on most of the PVC pipes except at lower elevation sites where shorter stakes are adequate and stream level metal guys are used as the calibration system. Slope, aspect, and canopy closure are recorded for all sites, as well as the initial stake tare reading on the ground (not all stake readings begin at zero).

A check sheet is established to keep the collected data organized. Depth measurements are routinely recorded at the stakes while driving by on the way to other field activities. Typically the Upper Lookout stakes on Rd. 1506 and Rd. 350 stakes read once every 3 weeks. The 1507 stakes are sampled only once or twice a year.

A special trip is made at least once per year to collect snow water equivalent measurements as a way of ground truthing the snow stake for snow moisture. The nearby snow stake is measured at the same time. Ground-truthing (snow water equivalent measurement) of each stake is conducted by taking three snow core measurements with the Mt Rose snow tube sampling equipment to establish a relationship between snow pack water equivalence and depth. The snow tube core sampler is pushed to soil surface interface, depth is recorded, and snow is extracted. The snow is weighed on a spring balance, the tare weight of the corer is subtracted, and actual snow weight is converted to millimeters of equivalent water.

This procedure generally follows the NRCS snow sampling procedure except only three cores are taken. If there is a complete snow pack around the snowstake 3 points are taken in the immediate vicinity of the snowstake (3 points approximately 1 meter equidistant from stake) and averaged. If the snow coverage is patchy, core sample placement becomes more subjective with limited spots where a useful core can be sampled. In the NRCS snowcourse a particular point not having any snow would be recorded as zero, but here all of our ground truthing cores have some amount of snow because points are selected for representation of the density of the snow (and not for representative depth). The % snowcover is estimated to gain a sense of snow patchiness.

Instrumentation: Mt. Rose snow core sampler. Note that a new snow core sampler was put into use on approximately March 1, 1999. The new scale is capable of measuring greater weights. Generally, comparable snow cores weigh less on the new scale in comparison to the older one.
Field Methods - MS007: Reference Stand snow course:
Description: At each site, snow is sampled at 10 points along a transect at 5 meter intervals. In 1988 the number of points was reduced to 5 per site. The snow tube core sampler is pushed to soil surface interface, depth is recorded, and snow is extracted. The length of the snow core is measured as an indicator of snow compaction. The snow is weighed on a spring balance, the tare weight of the corer is subtracted, and actual snow weight is converted to inches of equivalent water. In Reference Stands 4,12,13,14 paired transects in closed forest and open areas are taken. An open site was added at RS03 and RS26 for 1 year (WY90). At RS04, the open canopy site was moved to the road beginning WY91. Throughout the 1990's only RS04 and Wilcat RNA sites (RS13, RS14 open-closed canopy pairs) are measured, and only RS13 and RS14 after 2000. These measurement s were discontinued in 2003.
Instrumentation: Mt. Rose snow core sampler.
SUPPLEMENTAL INFORMATION:
The historic Reference Stand snow course was conducted throughout the 1980's and 1990's. The first measurement listed for a year is generally the first measurable snow of that year. However, the data suffers from not knowing the difference between no snow on the ground and no measurement of snow making a determination of snow melt-off difficult or impossible. Reference Stands with some snow measurements include RS03, RS04, RS05, RS12, RS13, RS14, RS18, RS26, and TS38. After 1993 only data from RS04 and two reference stands from the Wildcat RNA (RS13, RS14) are collected.
SITE DESCRIPTION:
Measurement sites include recent clearcuts and adjacent old-growth stands in the H. J. Andrews and vicinity from Reference Stands at 430 -1450 m elevation, and include two open-forest paired sites in the Wildcat Research Natural Area.
TAXONOMIC SYSTEM:
None
GEOGRAPHIC EXTENT:
The current snow course includes old-growth stands and adjacent open areas along the road network within the H. J. Andrews Experimental Forest of the western Oregon Cascades. The historic snow course survey includes some Andrews Reference Stands and Wildcat RNA sites.
ELEVATION_MINIMUM (meters):
430
ELEVATION_MAXIMUM (meters):
1450
MEASUREMENT FREQUENCY:
twice monthly
PROGRESS DESCRIPTION:
Active
UPDATE FREQUENCY DESCRIPTION:
annually
CURRENTNESS REFERENCE:
Ground condition