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 ID: 760824
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Slide1
LIGHT & HEAT
IN INLAND WATERS
Slide2Light spectrum at the top and bottom of the atmosphere
Slide3Measurable Properties of Light
Intensity
Quality
Both are dependent on absorption and reflection by the atmosphere
Slide4Fates of light in water
Slide5Shading of low order streams
Slide6Confluence of Kotorosl and Volga Rivers
Slide7Walker Lake
Slide8Extinction Coefficient
ν (nu) = extinction coefficient of light through water.Examples:Crystal Lake v = 0.19Turbid Pond v = 1 – 10Muddy Stock Tankv = >>10-150
Depends on:
Light absorption by water
Light scattered and absorbed by particles
Light absorbed by dissolved substances
v ~ 1/secci depth
Slide9Secci Disk
Slide10Typical Secci Depths
Crater Lake 40mCastle Lake 33mLake Texoma 0.75mSusquehanna RiverWest Shore >1.2mWest Center 0.32mEast Center 0.23mEast Shore 0.18m
Secci
Depth measured with
Secci
Disk in lakes and with a
Secci
Tube in running water.
Also measured with
Turbidimeter
(Jackson Turbidity Units- JTU)
Slide11Susquehanna River at Byer’s Island
Slide12Lakes Erie and St. Claire following major runoff event
Slide13Heat Budget for Lakes
SourcesSolar radiationSensible heat conductionStream InputSediment absorption of sunlightGeothermalBiogenic
Sinks
Evaporation
Sensible heat conduction
Back radiation from lake surface
Stream inputs (snow melt)
Surface outflow
Slide14Annual 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 = R
n
– E – H – Q
Slide15Slide16Lake Tahoe, CA-NV
Slide17Lake Tahoe, CA-NV
Slide18Lake Mendota, WI
Slide19Density and temperature
Slide20Stratification
Slide21Castle Lake Stratification
Slide22Slide23Lake 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
Slide24Fall turnover occurs when the center of gravity (M) approaches the center of the volume (X).
Slide25Slide26Martin Lake
Slide27Slide28dimictic – mixes twice per yearex: Castle Lake and Lake Mendotasmall temperate lakefreezes over during winter
amictic
– does not mix, permanently ice-covered
ex
: Lake Vanda, Antarctic
high latitude lake
Slide29Lake Vanda, Antarctica
Slide30Slide31Meromixis
Slide32Lake Nyos
Slide33Lakes Nyos (A&C) and Monoun (B&D)
Slide34Lake Kivu
Lake Kivu is one of the rift valley lakes on the border between Rwanda
and Congo
2,000X the size of Lake
Nyos
Geological sources of carbon dioxide
Biological conversion of carbon dioxide to methane
Lake area on a spreading zone and subject to earthquakes (last in 2008)
Slide35Polymixis in Clear Lake(Rueda et al. 2003)
Slide36Property
Rivers
Reservoirs
Lakes
Temperature variations
Rapid, large
Rapid in upper zone; slow
in lower portion
Slow, stable
Stratification
Rare
Irregular
Common (
monomictic
or
dimictic
)
Spatial differences
Headwaters cooler
becoming warmer downstream
Large fluctuations in upper reservoir, more stable in main body
Stratification common
Groundwater effects
High ratio groundwater to runoff
Small
Usually small (high in seepage lakes)
Tributary effects
Can be significant
Moderate to small
Small and localized
Shading effects
Considerable, especially in the headwaters
Small to negligible
Small to negligible
Winter
ice formation
Transitory
Usually transitory
Persistent
Ice scouring effects
Extensive
Minor
Minor