Light spectrum at the top and bottom of the atmosphere
Slide 3
Measurable Properties of Light Intensity Quality Both are
dependent on absorption and reflection by the atmosphere
Slide 4
Fates of light in water
Slide 5
Shading of low order streams
Slide 6
Confluence of Kotorosl and Volga Rivers
Slide 7
Walker Lake
Slide 8
Extinction Coefficient (nu) = extinction coefficient of light
through water. Examples: Crystal Lake v = 0.19 Turbid Pond v = 1 10
Muddy Stock Tank v = >>10-150 Depends on: Light absorption by
water Light scattered and absorbed by particles Light absorbed by
dissolved substances v ~ 1/secci depth
Slide 9
Secci Disk
Slide 10
Typical Secci Depths Crater Lake 40m Castle Lake 33m Lake
Texoma 0.75m Susquehanna River West Shore >1.2m West Center
0.32m East Center 0.23m East Shore 0.18m Secci Depth measured with
Secci Disk in lakes and with a Secci Tube in running water. Also
measured with Turbidimeter (JTU)
Slide 11
Susquehanna River at Byers Island
Slide 12
Lakes Erie and St. Claire following major runoff event
Slide 13
Heat Budget for Lakes Sources Solar radiation Sensible heat
conduction Stream Input Sediment absorption of sunlight Geothermal
Biogenic Sinks Evaporation Sensible heat conduction Back radiation
from lake surface Stream inputs (snow melt) Surface outflow
Slide 14
Annual Lake Heat Budget whereS = storage rate of heat in the
lake R n = net radiation E = evaporation H = sensible heat
transfer, conduction Q = advective heat transfers due to water
inflows and outflows S = R n E H Q
Slide 15
Slide 16
Lake Tahoe, CA-NV
Slide 17
Lake Mendota, WI
Slide 18
Density and temperature
Slide 19
Stratification
Slide 20
Castle Lake Stratification
Slide 21
Slide 22
Lake Classification Based on Thermal Stratification Patterns
1.Holomixis a.monomictic mixes once per year warm monomictic never
below 4C cold monomictic never above 4C ex: Lake Tahoe -large
volume and large depth -no winter ice cover
Slide 23
Fall turnover occurs when the center of gravity (M) approaches
the center of the volume (X).
Slide 24
Slide 25
Martin Lake
Slide 26
Slide 27
b.dimictic mixes twice per year ex: Castle Lake and Lake
Mendota small temperate lake freezes over during winter c.amictic
does not mix, permanently ice- covered ex: Lake Vanda, Antarctic
high latitude lake
Slide 28
Lake Vanda, Antarctica
Slide 29
Slide 30
Meromixis
Slide 31
Lake Nyos
Slide 32
Lakes Nyos (A&C) and Monoun (B&D)
Slide 33
Polymixis in Clear Lake (Rueda et al. 2003)
Slide 34
PropertyRiversReservoirsLakes Temperature variationsRapid,
largeRapid in upper zone; slow in lower portion Slow, stable
StratificationRareIrregularCommon (monomictic or dimictic) Spatial
differencesHeadwaters cooler becoming warmer downstream Large
fluctuations in upper reservoir, more stable in main body
Stratification common Groundwater effectsHigh ratio groundwater to
runoff SmallUsually small (high in seepage lakes) Tributary
effectsCan be significantModerate to smallSmall and localized
Shading effectsConsiderable, especially in the headwaters Small to
negligible Winter ice formationTransitoryUsually
transitoryPersistent Ice scouring effectsExtensiveMinor