Snow Hydrology Flashcards
Stamp Sands
left-over copper mine, use it on roads on snow
Importance of Snow
what’s society used to, preparation, economics, recreation, transportation, property damage, replenish water storage
Snow Hydrology
understanding and predicting the physical process of snow accumulation (how much), ablation (reduction), and melt water runoff (where ends up)
Snow Hydrology Issues
quantity of water in snow packs, magnitude and rate of water lost by sublimation, timing rate & magnitude of snow melt, and rate of melt water
Snow Crystal Formation
different temps form different crystals
Why does snow look blue?
reflects off of sky (which is blue); shortwave radiation
Lake Effect
Causes bands of snow
Snow Cover Distribution Types
Macroscale, Mesoscale, Microscale
Macroscale
distances 10-1,000 km (here to Raystown)
Mesoscale
distances 100 m to 10 km (Huntingdon)
Microscale
distances 10-100 m (here to baseball field)
Effect of Topography on Snow Distribution
depth increases with elevation (more snowfall events and lower evaporation/melt), but not only elevation; must consider other factors (slope, aspect, temp, vegetation, etc.)
Aspect
direction you’re facing
Effect of Vegetation on Snow Distribution
turbulent air flow above and within canopy, direct interception of snow by canopy elements; related to type, density, and nearby areas
Effect of Forested Environments on Snow Distribution
conifers are efficient interceptors, and cohesion makes it last longer, more accumulation in clearings (difference occurs during storms & caused by sublimation and interception)
Effect of Open Environments on Snow Distribution
relative accumulation on different landscapes in open grassland
Open Environment
highly exposed terrain, differences in vegetation/terrain produce variation in accumulation
Hydrologic Influences of Blowing Snow
redistribution of snow water equivalent & loss of water by sublimation
Blowing Snow Transportation
creep (roll), saltation (bounce), turbulent diffusion (suspended)
Blowing Snow: Sublimation Losses
snow particles more exposed to atmosphere during wind transport; depends on transport rate and distance, temp, humidity, wind speed, solar radiation
Snow Pack
porous medium (ice + air + liquid water), layers of different types, ice in crystals/grains bonded together, gets stronger with more compaction
Snow Pack SWE
snow depth x (snow density/water density); height of water if snow cover melted
Snow Pack Grain Size
average size of characteristic grains within a mass of snow (mm)
Snow Pack Temperature
variation of temperature between top and bottom (temp gradient & largely determined by thickness and mean surface temp) OR no temp gradient (isothermal)
Diurnal
occuring every day
Snow Energy Exchange: Radiation
transfer of energy by electromagnetic waves
Snow Energy Exchange: Conduction
molecule to molecule contact
Snow Energy Exchange: Convection
involves mixing
Snow Energy Exchange: Advection
energy transfers by mass transport
Factors Contributing to Energy Transfer
wind (increase wind and mixing, sensible heat exchange), water vapor (pressure gradient between snow and air, latent heat exchange), radiation (shortwave and longwave), advected heat, and soil contact
Velocity of Water Flow Through Snow
2-60 cm/min; depends on pack structure, condition prior to water, and water on surface
Water Flow Through Homogeneous Snow
thin film of water surrounds snow grains; laminar flow
Water Flow Through Heterogeneous Snow
preferential flow paths; ice layers (from melt and refreezing, relatively impermeable, goes laterally)
Snow Pillows
measure weight
Snow Courses
transects with snow depth and density
Snow Tubes
measure volume and mass of cores
Snow Pits
measure vertical profiles of SWE and other pack variables
Airborne Snow Survey Program
measure radiation coming out of ground; knowing what should be radiating from that point, we can measure depth of snow
Satellite Areal Extent of Snow Cover
measure snow water equivallent
