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LIGHT & HEAT. IN INLAND WATERS. Light spectrum at the top and bottom of the atmosphere. Measurable Properties of Light. Intensity Quality Both are dependent on absorption and reflection by the atmosphere. Fates of light in water. Shading of low order streams.

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Light heat

LIGHT & HEAT

IN INLAND WATERS



Measurable properties of light
Measurable Properties of Light

  • Intensity

  • Quality

    Both are dependent on absorption and reflection by the atmosphere




Confluence of kotorosl and volga rivers
Confluence of Kotorosl and Volga Rivers



Extinction coefficient
Extinction Coefficient

ν (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


Secci disk
Secci Disk


Typical secci depths
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)




Heat budget for lakes
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


Annual lake heat budget
Annual Lake Heat Budget

where S = storage rate of heat in the lake

Rn = net radiation

E = evaporation

H = sensible heat transfer, conduction

Q = advective heat transfers due to water

inflows and outflows

S = Rn – E – H – Q







Lake classification based on thermal stratification patterns
Lake Classification Based on Thermal Stratification Patterns

  • Holomixis

    • monomictic – mixes once per year

      • warm monomictic – never below 4°C

      • cold monomictic – never above 4°C

      • ex: Lake Tahoe

        • large volume and large depth

        • no winter ice cover


Fall turnover occurs when the center of gravity m approaches the center of the volume x
Fall turnover occurs when the center of gravity (M) approaches the center of the volume (X).


Martin lake
Martin Lake approaches the center of the volume (X).


Light heat

  • dimictic approaches the center of the volume (X). – mixes twice per year

    • ex: Castle Lake and Lake Mendota

      • small temperate lake

      • freezes over during winter

  • amictic – does not mix, permanently ice-covered

    • ex: Lake Vanda, Antarctic

      • high latitude lake


Lake vanda antarctica
Lake Vanda, Antarctica approaches the center of the volume (X).


Meromixis
Meromixis approaches the center of the volume (X).


Lake nyos
Lake approaches the center of the volume (X).Nyos


Lakes nyos a c and monoun b d
Lakes approaches the center of the volume (X).Nyos(A&C) and Monoun(B&D)


Polymixis in clear lake rueda et al 2003
Polymixis approaches the center of the volume (X). in Clear Lake(Rueda et al. 2003)