The BOREAS Information System
Hydrology (HYD)


HYD-3: Distributed Energy Transfer Modeling in Snow and Soil for Boreal Ecosystems


P.I.(s): Robert (Bert) Davis -- U.S. Army Cold Regions Research & Engineering Lab (CRREL)

Objectives: To model the spatial and temporal distributions of critical snow pack properties and processes at scales up to about 1 square kilometer, several patches within the two intensive study sites, and to develop tools linking model predictions to remote sensing. The three principle objectives of the project are:

The study is focusing on the winter and thaw periods, and on the relatively small spatial scale (e.g. treestands and small watersheds).

View a Web-based "poster" on this research.

HYD-3 Data Sets

  • Sub-canopy Radiation from OJP
  • Canopy Wind Speed (2 meters SSA-OJP)
  • Snow Temperature Profiles
  • Canopy Density
  • Snow Depth and Water Equivalent

  • Get some HYD-3 data using FTP (BOREAS Investigators only, password required). [FTP Help]

    HYD-3 BOREAS Operations in 1994


    Objectives:
    The goal of this project is to model the spatial and temporal distributions of critical snow pack properties and processes at scales up to about 1 square kilometer and to develop tools linking model predictions to remote sensing. The three principal objectives of the project are:

    1. to classify the boreal forest biome based on the spatial distribution of tree stands, vegetation and soils, and to establish land cover units which have similar attributes in the context of the upper and lower boundary conditions required by energy and mass transfer models.
    2. to investigate methods for incorporating the effects of different tree canopy and stem characteristics into stand scale estimates of snow properties and surface energy exchange.
    3. to identify the capabilities and limitations of remote sensing measurements to monitor the state of the snow pack.
    Data Type Equipment
    Snow water equivalence (SWE)
  • centimeter scale
  • 100 cc snow density cutter
  • electronic top loader balance
  • Canadian Snow Sampler
    		•
    Snow pack properties:
  • snow pack temperatures
  • snow density profile
  • air permeability of snow
  • grain size distribution
  • snow microstructure
    		•
  • digital thermometer
  • 100 cc snow density cutter
  • double chamber permeameter
  • sieves and photos
  • sample collection and image analysis
    		•
    Snow distribution around conifer trees
    (measurement of tree well geometry)    		 centimeter scale
    Canopy closure forest densiometer
  • Within canopy wind speed and direction
  • air temperature
  • relative humidity
    		•
  • RM Young wind monitor
  • 107 Temperature probe
  • 207 RH probe
    		•
    Subcanopy radiation and temp.
  • solar radiation
  • thermal radiation
  • snow surface temperature
  • canopy temperature
    		•
  • Eppley pyranometer
  • Eppley pyrgeometer
  • radiant thermometer
  • radiant thermometer
    		•
    Spectral reflectance of the snow surface ASD Personal Spectrometer
    Radiation Scatterers:
  • number of needles and twigs
  • in randomly selected areas
  • on several trees
    		•  manual labor - counting needles
    and measuring twig lengths

    Places and Times of Measurement:
    FFC-W 1994: SWE, snow pack properties, snow distribution, and canopy closure were measured at SSA-OJP, OA, and the Gamma flight line BP-110, as well as NSA-YJP, OJP, and OBS. Within canopy wind speed, wind direction, and subcanopy solar radiation were measured in SSA-OJP and OA.
    FFC-T 1994: SWE, snow pack properties, and snow distribution were measured at NSA-YJP, OJP and OBS. Canopy closure was measured at NSA: YJP and OBS. Subcanopy solar radiation was measured at NSA: YJP and OBS. Spectral reflectance measurements of the snow were made at a variety of incidence angles and azimuths at NSA-OBS.
    March 1995: The following measurements were made at NSA, OBS: snow distribution, snow pack properties, canopy closure, subcanopy solar and thermal radiation, snow surface and canopy temperatures, as well as within canopy wind speed, wind direction, air temperature and relative humidity. Additionally, we quantified radiative scatterers (needles and twigs) at 25, randomly selected, 1000 cc areas on five different trees to be incorporated into a canopy radiation model.


    Problems and Caveats:

    1. Low values of wind speed collected during FFC-W in NSA, OJP are close to the threshold value for the instrument and therefore are not accurate.
    2. Studies have shown that densiometer derived canopy closure is not the most precise method of determining canopy closure, but that it is the best available "quick and easy" method. Data are considered approximate measures of canopy closure.

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    Last Updated: October 21, 1997