Remote Sensing of WaterRemote Sensing of Wateraviris.gl.fcen.uba.ar/Curso_SR/biblio_sr/Chapter11_Water.pdfRemote Sensing of WaterRemote Sensing of Water • 74% of the Earth’s surface

Carolina Distinguished ProfessorDepartment of Geography

University of South CarolinaColumbia, South Carolina 29208

[email protected]

Carolina Distinguished ProfessorCarolina Distinguished ProfessorDepartment of GeographyDepartment of Geography

University of South CarolinaUniversity of South CarolinaColumbia, South Carolina 29208Columbia, South Carolina 29208

jrjensenjrjensen@@scsc..eduedu

Remote Sensing of WaterRemote Sensing of WaterRemote Sensing of Water

• 74% of the Earth’s surface is water• 97% of the Earth’s volume of water is in the saline oceans• 2.2% in the permanent icecap • Only 0.02% is in freshwater streams, river, lakes, reservoirs• Remaining water is in:

- underground aquifers (0.6%), - the atmosphere in the form of water vapor (0.001%)

•• 74% of the Earth74% of the Earth’’s surface is waters surface is water•• 97% of the Earth97% of the Earth’’s volume of water is in the saline oceanss volume of water is in the saline oceans•• 2.2% in the permanent icecap 2.2% in the permanent icecap •• Only 0.02% is in freshwater streams, river, lakes, reservoirsOnly 0.02% is in freshwater streams, river, lakes, reservoirs•• Remaining water is in: Remaining water is in:

-- underground aquifers (0.6%), underground aquifers (0.6%), -- the atmosphere in the form of water vapor (0.001%)the atmosphere in the form of water vapor (0.001%)

Earth: The Water PlanetEarth: The Water PlanetEarth: The Water Planet

Jensen, 2000Jensen, 2000Jensen, 2000

The total radiance, (Lt ) recorded by a remote sensing system over a waterbody is a function of the electromagnetic energy from four sources:

Lt = Lp + Ls + Lv + Lb • Lp is the the radiance recorded by a sensor resulting from the downwelling solar (Esun ) and sky (Esky ) radiation. This is unwanted path radiance that never reaches the water. • Ls is the radiance that reaches the air-water interface (free-surface layer or boundary layer) but only penetrates it a millimeter or so and is then reflected from the water surface. This reflected energy contains spectral information about the near-surface characteristics of the water. • Lv is the radiance that penetrates the air-water interface, interacts with the organic/inorganic constituents in the water, and then exits the water column without encountering the bottom. It is called subsurface volumetric radiance and provides information about the internal bulk characteristics of the water column • Lb is the radiance that reaches the bottom of the waterbody, is reflected from it and propagates back through the water column, and then exits the water column. This radiance is of value if we want information about the bottom (e.g., depth, color).

The total radiance, (The total radiance, (LLtt ) recorded by a remote sensing system over a ) recorded by a remote sensing system over a waterbody waterbody is a is a function of the electromagnetic energy from four sources:function of the electromagnetic energy from four sources:

LLtt = = LLpp + L+ Lss + + LLvv + + LLbb•• LLpp is the the radiance recorded by a sensor resulting is the the radiance recorded by a sensor resulting from tfrom the he downwellingdownwelling solar (solar (EEsunsun ) ) and sky (and sky (EEskysky ) radiation. This is unwanted ) radiation. This is unwanted path radiancepath radiance that never reaches the water.that never reaches the water.•• LLss is the radiance that reaches the airis the radiance that reaches the air--water interface water interface ((freefree--surface layersurface layer or or boundary boundary layerlayer) but only penetrates it a millimeter or so and is then reflecte) but only penetrates it a millimeter or so and is then reflected from the water d from the water surface. This reflected energy contains spectral information abosurface. This reflected energy contains spectral information about the nearut the near--surface surface characteristics of the water.characteristics of the water.•• LLvv is the radiance that penetrates the airis the radiance that penetrates the air--water interface, interacts with the water interface, interacts with the organic/inorganic constituents in the water, and then exits the organic/inorganic constituents in the water, and then exits the water column without water column without encountering the bottom. It is called encountering the bottom. It is called subsurface volumetric radiancesubsurface volumetric radiance and provides and provides information about the internal bulk characteristics of the waterinformation about the internal bulk characteristics of the water columncolumn•• LLbb is the radiance that reaches the is the radiance that reaches the bottombottom of the of the waterbodywaterbody, is reflected from it and , is reflected from it and propagates back through the water column, and then exits the watpropagates back through the water column, and then exits the water column. This er column. This radiance is of value if we want information about the bottom (e.radiance is of value if we want information about the bottom (e.g., depth, color). g., depth, color).

Water Surface, Subsurface Volumetric, and Bottom RadianceWater Surface, Subsurface Volumetric, and Bottom RadianceWater Surface, Subsurface Volumetric, and Bottom Radiance


Total radiance, (Lt ) recorded by a remote sensing system over water is a function of the electromagnetic energy received from:

Lp = atmospheric path radianceLs = free-surface layer

reflectanceLv = subsurface volumetric

reflectanceLb = bottom reflectance

Total radiance, (Total radiance, (LLtt ) recorded by ) recorded by a remote sensing system over a remote sensing system over water is a function of the water is a function of the electromagnetic energy received electromagnetic energy received from:from:

LLpp = atmospheric path radiance= atmospheric path radianceLLss = free= free--surface layer surface layer

reflectancereflectanceLLvv = subsurface volumetric = subsurface volumetric

reflectancereflectanceLLbb = bottom reflectance= bottom reflectance


The total radiance, (Lt ) recorded by a remote sensing system over a waterbody is a function of the electromagnetic energy from four sources:

Lt = Lp + Ls + Lv + Lb • Lp is the the radiance recorded by a sensor resulting from the downwelling solar (Esun ) and sky (Esky ) radiation. This is unwanted path radiance that never reaches the water. • Ls is the radiance that reaches the air-water interface (free-surface layer or boundary layer) but only penetrates it a millimeter or so and is then reflected from the water surface. This reflected energy contains spectral information about the near-surface characteristics of the water. • Lv is the radiance that penetrates the air-water interface, interacts with the organic/inorganic constituents in the water, and then exits the water column without encountering the bottom. It is called subsurface volumetric radiance and provides information about the internal bulk characteristics of the water column • Lb is the radiance that reaches the bottom of the waterbody, is reflected from it and propagates back through the water column, and then exits the water column. This radiance is of value if we want information about the bottom (e.g., depth, color).

The total radiance, (The total radiance, (LLtt ) recorded by a remote sensing system over a ) recorded by a remote sensing system over a waterbody waterbody is a is a function of the electromagnetic energy from four sources:function of the electromagnetic energy from four sources:

LLtt = = LLpp + L+ Lss + + LLvv + + LLbb•• LLpp is the the radiance recorded by a sensor resulting is the the radiance recorded by a sensor resulting from tfrom the he downwellingdownwelling solar (solar (EEsunsun ) ) and sky (and sky (EEskysky ) radiation. This is unwanted ) radiation. This is unwanted path radiancepath radiance that never reaches the water.that never reaches the water.•• LLss is the radiance that reaches the airis the radiance that reaches the air--water interface water interface ((freefree--surface layersurface layer or or boundary boundary layerlayer) but only penetrates it a millimeter or so and is then reflecte) but only penetrates it a millimeter or so and is then reflected from the water d from the water surface. This reflected energy contains spectral information abosurface. This reflected energy contains spectral information about the nearut the near--surface surface characteristics of the water.characteristics of the water.•• LLvv is the radiance that penetrates the airis the radiance that penetrates the air--water interface, interacts with the water interface, interacts with the organic/inorganic constituents in the water, and then exits the organic/inorganic constituents in the water, and then exits the water column without water column without encountering the bottom. It is called encountering the bottom. It is called subsurface volumetric radiancesubsurface volumetric radiance and provides and provides information about the internal bulk characteristics of the waterinformation about the internal bulk characteristics of the water columncolumn•• LLbb is the radiance that reaches the is the radiance that reaches the bottombottom of the of the waterbodywaterbody, is reflected from it and , is reflected from it and propagates back through the water column, and then exits the watpropagates back through the water column, and then exits the water column. This er column. This radiance is of value if we want information about the bottom (e.radiance is of value if we want information about the bottom (e.g., depth, color). g., depth, color).

Water Surface, Subsurface Volumetric, and Bottom RadianceWater Surface, Subsurface Volumetric, and Bottom RadianceWater Surface, Subsurface Volumetric, and Bottom Radiance


Examples of Absorption of Near-Infrared Radiant Flux by Water and Sunglint

Examples of Absorption of NearExamples of Absorption of Near--Infrared Infrared Radiant Flux by Water and Radiant Flux by Water and SunglintSunglint

Black and white infrared photograph of water bodies in Florida

Black and white infrared photograph Black and white infrared photograph of water bodies in Floridaof water bodies in Florida

Black and white infrared photograph with sunglint

Black and white infrared Black and white infrared photograph with photograph with sunglintsunglint


Absorption and Scattering

Attenuation in Pure Water

AbsorptionAbsorption and and Scattering Scattering

Attenuation in Attenuation in Pure WaterPure Water

Molecular water absorption dominates in the ultraviolet (<400 nm) and in the yellow through the near-infrared portion of the spectrum (>580 nm). Almost all of the incident near-infrared and middle-infrared (740 - 2500 nm) radiant flux entering a pure water body is absorbed with negligible scattering taking place.

Molecular water Molecular water absorptionabsorption dominates in the ultraviolet dominates in the ultraviolet (<400 (<400 nmnm) and in the yellow ) and in the yellow through the nearthrough the near--infrared infrared portion of the spectrum (>580 portion of the spectrum (>580 nmnm). Almost all of the ). Almost all of the incident nearincident near--infrared and infrared and middlemiddle--infrared (740 infrared (740 -- 2500 2500 nmnm) radiant flux entering a ) radiant flux entering a pure water body is absorbed pure water body is absorbed with negligible scattering with negligible scattering taking place. taking place.


Absorption and Scattering

Attenuation in Pure Water

Absorption and Absorption and ScatteringScattering

Attenuation in Attenuation in Pure WaterPure Water

Scattering in the water column is important in the violet, dark blue, and light blue portions of the spectrum (400 - 500 nm). This is the reason water appears blue to our eyes. The graph truncates the absorption data in the ultraviolet and in the yellow through near-infrared regions because the attenuation is so great.

ScatteringScattering in the water column in the water column is important in the violet, dark is important in the violet, dark blue, and light blue portions of blue, and light blue portions of the spectrum (400 the spectrum (400 -- 500 500 nmnm). ). This is the reason water This is the reason water appears blue to our eyes. The appears blue to our eyes. The graph truncates the absorption graph truncates the absorption data in the ultraviolet and in the data in the ultraviolet and in the yellow through nearyellow through near--infrared infrared regions because the attenuation regions because the attenuation is so great.is so great.


The best wavelength region for discriminating land from pure water is in the near-infrared and middle-infrared from 740 - 2,500 nm.

In the near- and middle-infrared regions, water bodies appear very dark, even black, because they absorb almost all of the incident radiant flux, especially when the water is deep and pure and contains little suspended sediment or organic matter.

The best wavelength region for discriminating land from pure The best wavelength region for discriminating land from pure water is in the nearwater is in the near--infrared and middleinfrared and middle--infrared from infrared from 740 740 -- 2,5002,500 nmnm. .

In the nearIn the near-- and middleand middle--infrared regions, water bodies appear infrared regions, water bodies appear very dark, even black, because they absorb almost all of the very dark, even black, because they absorb almost all of the incident radiant flux, especially when the water is deep and incident radiant flux, especially when the water is deep and pure and contains little suspended sediment or organic matter.pure and contains little suspended sediment or organic matter.

Monitoring the Surface Extent of Water BodiesMonitoring the Surface Extent of Water BodiesMonitoring the Surface Extent of Water Bodies


Water PenetrationWater PenetrationWater Penetration

SPOT Band 1 (0.5 - 0.59 μm) greenSPOT Band 1 (0.5 SPOT Band 1 (0.5 -- 0.59 0.59 μμm) m) greengreen SPOT Band 2 (0.61 - 0.68 μm) redSPOT Band 2 (0.61 SPOT Band 2 (0.61 -- 0.68 0.68 μμm) m) redred SPOT Band 3 (0.79 - 0.89 μm) NIRSPOT Band 3 (0.79 SPOT Band 3 (0.79 -- 0.89 0.89 μμm) m) NIRNIR

PalancarPalancar ReefReef Caribbean SeaCaribbean Sea

Cozumel Cozumel IslandIsland


When conducting water-quality studies using remotely sensed data, we are usually most interested in measuring the subsurface volumetric radiance, Lv exiting the water column toward the sensor. The characteristics of this radiant energy are a function of the concentration of pure water (w), inorganic suspended minerals (SM), organic chlorophyll a (Chl), dissolved organic material (DOM), and the total amount of absorption and scattering attenuation that takes place in the water column due to each of these constituents, c(λ

):

Lv = f [wc(λ) , SMc(λ) , Chlc(λ) , wc(λ) ].

It is useful to look at the effect that each of these constituents has on the spectral reflectance characteristics of a water column.

When conducting waterWhen conducting water--quality studies using remotely sensed data, we are usually quality studies using remotely sensed data, we are usually most interested in measuring the subsurface volumetric radiance,most interested in measuring the subsurface volumetric radiance, LLv v exiting the exiting the water column toward the sensor. The characteristics of this radiwater column toward the sensor. The characteristics of this radiant energy are a ant energy are a function of the concentration of pure water (function of the concentration of pure water (ww), inorganic suspended minerals ), inorganic suspended minerals ((SMSM), organic chlorophyll ), organic chlorophyll aa ((ChlChl), dissolved organic material (), dissolved organic material (DOMDOM), and the total ), and the total amount of absorption and scattering attenuation that takes placeamount of absorption and scattering attenuation that takes place in the water in the water column due to each of these constituents, column due to each of these constituents, c(c(λλ))::

LLvv = f = f [[wwcc((λλ)) ,, SMSMcc((λλ)) ,, ChlChlcc((λλ)) ,, wwcc((λλ)) ].].

It is useful to look at the effect that each of these constituenIt is useful to look at the effect that each of these constituents has on the spectral ts has on the spectral reflectance characteristics of a water column.reflectance characteristics of a water column.

Spectral Response of Water as a Function of Organic and Inorganic Constituents - Monitoring Suspended Minerals (Turbidity),

Chlorophyll, and Dissolved Organic Matter

Spectral Response of Water as a Function of Organic and Spectral Response of Water as a Function of Organic and Inorganic Constituents Inorganic Constituents -- Monitoring Suspended Minerals (Turbidity), Monitoring Suspended Minerals (Turbidity),

Chlorophyll, and Dissolved Organic MatterChlorophyll, and Dissolved Organic Matter


Minerals such as silicon, aluminum, and iron oxides are found in suspension in most natural water bodies. The particles range from fine clay particles ( 3 - 4 μm in diameter), to silt (5 - 40 μm), to fine-grain sand (41 - 130 μm), and coarse grain sand (131 - 1250 μm). Sediment comes from a variety of sources including agriculture erosion, weathering of mountainous terrain, shore erosion caused by waves or boat traffic, and volcanic eruptions (ash). Most suspended mineral sediment is concentrated in the inland and nearshore water bodies. Clear, deep ocean (Case 1 water) far from shore rarely contains suspended minerals greater than 1 μm in diameter.

Minerals such as silicon, aluminum, and iron oxides are found Minerals such as silicon, aluminum, and iron oxides are found in suspension in most natural water bodies. The particles in suspension in most natural water bodies. The particles range from fine clay particles ( 3 range from fine clay particles ( 3 -- 4 4 μμm in diameter), to silt m in diameter), to silt (5 (5 -- 40 40 μμm), to finem), to fine--grain sand (41 grain sand (41 -- 130 130 μμm), and coarse grain m), and coarse grain sand (131 sand (131 -- 1250 1250 μμm). Sediment comes from a variety of m). Sediment comes from a variety of sources including agriculture erosion, weathering of sources including agriculture erosion, weathering of mountainous terrain, shore erosion caused by waves or boat mountainous terrain, shore erosion caused by waves or boat traffic, and volcanic eruptions (ash). Most suspended mineral traffic, and volcanic eruptions (ash). Most suspended mineral sediment is concentrated in the inland and sediment is concentrated in the inland and nearshorenearshore water water bodies. Clear, deep ocean (Case 1 water) far from shore rarely bodies. Clear, deep ocean (Case 1 water) far from shore rarely contains suspended minerals greater than 1 contains suspended minerals greater than 1 μμm in diameter. m in diameter.

Spectral Response of Water as a Function of Inorganic and Organic Constituents

Spectral Response of Water as a Function of Spectral Response of Water as a Function of Inorganic and Organic ConstituentsInorganic and Organic Constituents


Space Shuttle Photograph of the

Suspended Sediment Plume at the Mouth of the Mississippi River near New

Orleans, Louisiana

Space Shuttle Space Shuttle Photograph of the Photograph of the

Suspended Sediment Suspended Sediment Plume at the Mouth Plume at the Mouth of the Mississippi of the Mississippi River near New River near New

Orleans, LouisianaOrleans, Louisiana

STS #51STS #51STS #51


Secchi DiskSecchi Secchi DiskDisk

Used to measure suspended sediment

in water bodies

Used to measure Used to measure suspended sediment suspended sediment

in water bodiesin water bodiesJensen, 2000Jensen, 2000Jensen, 2000

In situ Spectroradiometer Measurement of Water with Various Suspended Sediment and Chlorophyll a Concentrations

In situIn situ Spectroradiometer Measurement of Water with Spectroradiometer Measurement of Water with Various Suspended Sediment and Chlorophyll Various Suspended Sediment and Chlorophyll aa ConcentrationsConcentrations

Lodhi et al., 1997; Jensen, 2000;

LodhiLodhi et al., 1997; et al., 1997; Jensen, 2000;Jensen, 2000;

90 cm

165 cm15Þ

Spectroradiometer

35 cm diameter

water surface

diameter = 3.66 m

In situ Spectroradiometer Measurement of Clear Water

with Various Levels of Clayey and Silty Soil Suspended Sediment Concentrations

In situIn situ Spectroradiometer Spectroradiometer Measurement of Clear Water Measurement of Clear Water

with Various Levels of Clayey with Various Levels of Clayey and and SiltySilty Soil Suspended Soil Suspended Sediment ConcentrationsSediment Concentrations

Lodhi et al., 1997; Jensen, 2000

LodhiLodhi et al., 1997; et al., 1997; Jensen, 2000Jensen, 2000

clayclayclay

siltsiltsilt

400 450 500 550 600 650 700 750 800 850 9000

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400 450 500 550 600 650 700 750 800 850 9000

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450 500 550

a.

b.

Clayey soil

Silty soil Reflectance peak shifts toward longer wavelengths as more suspended sediment is added

Reflectance peak shifts toward Reflectance peak shifts toward longer wavelengths as more longer wavelengths as more suspended sediment is addedsuspended sediment is added

Plankton is the generic term used to describe all the living organisms (plant and animal) present in a waterbody that cannot resist the current (unlike fish). Plankton may be subdivided further into algal plant organisms (phytoplankton), animal organisms (zoolankton), bacteria (bacterioplankton), and lower platn forms such as algal fungi. Phytoplankton are small single-celled plants smaller than the size of a pinhead. Phytoplankton, like plants on land, are composed of substances that contain carbon. Phytoplankton sink to the ocean or water-body floor when they die. All phytoplankton in water bodies contain the photosynthetically active pigment chlorpohyll a. There are two other phytoplankton photosynthesizing agents: carotenoids and phycobilins. Bukata et al (1995) suggest, however, that chlorphyll a is a reasonable surrogate for the organic component of optically complex natural waters.

PlanktonPlankton is the generic term used to describe all the living organisms (is the generic term used to describe all the living organisms (plant plant and animal) present in a and animal) present in a waterbodywaterbody that cannot resist the current (unlike that cannot resist the current (unlike fish). Plankton may be subdivided further into fish). Plankton may be subdivided further into algal algal plant organisms plant organisms ((phytoplanktonphytoplankton), animal organisms (), animal organisms (zoolanktonzoolankton), bacteria (), bacteria (bacteriobacterio-- planktonplankton), and lower ), and lower platn platn forms such as forms such as algal algal fungifungi. . PhytoplanktonPhytoplankton are are small singlesmall single--celled plants smaller than the size of a pinhead. celled plants smaller than the size of a pinhead. PhytoplanktonPhytoplankton, , like plants on land, are composed of substances that contain carlike plants on land, are composed of substances that contain carbon. bon. Phytoplankton Phytoplankton sink to the ocean or watersink to the ocean or water--body floor when they die. All body floor when they die. All phytoplankton phytoplankton in water bodies contain the in water bodies contain the photosynthetically photosynthetically active active pigment pigment chlorpohyllchlorpohyll aa. There are two other . There are two other phytoplankton phytoplankton photosynthesizing agents: photosynthesizing agents: carotenoids carotenoids and and phycobilinsphycobilins. . Bukata Bukata et al (1995) et al (1995) suggest, however, that suggest, however, that chlorphyll chlorphyll aa is a reasonable surrogate for the organic is a reasonable surrogate for the organic component of optically complex natural waters. component of optically complex natural waters.

Spectral Response of Water as a Function of Organic Constituents - Plankton

Spectral Response of Water as a Function of Spectral Response of Water as a Function of Organic Constituents Organic Constituents -- PlanktonPlankton


Micrograph of A Photosynthesizing Diatom

Micrograph Micrograph of A of A Photosynthesizing DiatomPhotosynthesizing Diatom

Micrograph of Blue Reflected Light from a

Green Algae Cell (Micrasterias sp.).

Micrograph Micrograph of Blue of Blue Reflected Light from a Reflected Light from a

Green Algae Cell Green Algae Cell ((Micrasterias spMicrasterias sp.). .).

chloroplast material

cell wall


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Algae-Laden Water with Various Suspended Sediment Concentrations

Percent reflectance of algae-laden water with various concentrations of suspended sediment ranging from 0 - 500 mg/l

Percent reflectance of algaePercent reflectance of algae--laden laden water with various concentrations water with various concentrations of suspended sediment ranging of suspended sediment ranging from 0 from 0 -- 500 mg/l500 mg/l

Percent reflectance of clear and algae-laden water based on in situ spectroradiometer measurement. Note the strong chlorophyll a absorption of blue light between 400 and 500 nm and strong chlorophyll a absorption of red light at approximately 675 nm

Percent reflectance of clear and Percent reflectance of clear and algaealgae--laden water based onladen water based on in situin situ spectroradiometer measurement. spectroradiometer measurement. Note the strong Note the strong chlorophyll achlorophyll a absorption of blue light between absorption of blue light between 400 and 500 400 and 500 nm nm and strong and strong chlorophyll achlorophyll a absorption of red light absorption of red light at approximately 675 at approximately 675 nmnm

Han, 1997;Jensen, 2000Han, 1997;Han, 1997;

Jensen, 2000Jensen, 2000

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Chlorophyll in Ocean WaterChlorophyll in Ocean WaterChlorophyll in Ocean Water

A remote estimate of near-surface chlorophyll concentration generally constitutes an estimate of near-surface biomass (or primary productivity) for deep ocean (Case 1) water where there is little danger of suspended mineral sediment contamination.

Numerous studies have documented a relationship between selected spectral bands and ocean chlorophyll (Chl) concentration using the equation:

Chl = x [L(λ1 )/L(λ2 )]y

Where L(λ1 ) and L(λ2 ) are the upwelling radiances at selected wavelengths recorded by the remote sensing system and x and y are empirically derived constants.

The most important SeaWiFS algorithms involve the use of band ratios of 443/355 nm and 490/555 nm.

A remote estimate of nearA remote estimate of near--surface chlorophyll concentration generally constitutes surface chlorophyll concentration generally constitutes an estimate of nearan estimate of near--surface biomass (or primary productivity) for deep ocean surface biomass (or primary productivity) for deep ocean (Case 1) water where there is little danger of suspended mineral(Case 1) water where there is little danger of suspended mineral sediment sediment contamination.contamination.

Numerous studies have documented a relationship between selectedNumerous studies have documented a relationship between selected spectral bands spectral bands and ocean chlorophyll (and ocean chlorophyll (ChlChl) concentration using the equation:) concentration using the equation:

ChlChl = x [= x [L(L(λλ

11 )/L()/L(λλ

22 ))]]yy

Where Where L(L(λλ

11 )) and and L(L(λλ

22 )) are the upwelling are the upwelling radiances radiances at selected wavelengths at selected wavelengths recorded recorded by tby the remote sensing system and he remote sensing system and xx and and yy are empirically derived are empirically derived constants. constants.

The most important SeaWiFS algorithms involve the use of band raThe most important SeaWiFS algorithms involve the use of band ratios of 443/355 tios of 443/355 nm and 490/555 nm. nm and 490/555 nm.

Global Chlorophyll a (g/m3) Derived from SeaWiFS Imagery Obtained from September 3, 1997 through December 31, 1997Global Chlorophyll Global Chlorophyll aa (g/m(g/m33) Derived from SeaWiFS Imagery ) Derived from SeaWiFS Imagery Obtained from September 3, 1997 through December 31, 1997Obtained from September 3, 1997 through December 31, 1997


True-color SeaWiFS image of the Eastern U.S. on September 30, 1997 TrueTrue--color SeaWiFS image of the color SeaWiFS image of the

Eastern U.S. on September 30, 1997Eastern U.S. on September 30, 1997Chlorophyll a distribution

on September 30, 1997 derived from SeaWiFS data

Chlorophyll Chlorophyll aa distribution distribution on September 30, 1997 on September 30, 1997

derived from SeaWiFS dataderived from SeaWiFS dataJensen, 2000Jensen, 2000Jensen, 2000

Sunlight penetrates into the water column a certain photic depth (the vertical distance from the water surface to the 1 percent subsurface irradiance level). Phytoplankton within the photic depth of the water column consume nutrients and convert them into organic matter via photosynthesis. This is called primary production. Zooplankton eat the phytoplankton and create organic matter. Bacterioplankton decompose this organic matter. All this conversion introduces dissolved organic matter (DOM) into oceanic, nearshore, and inland water bodies. In certain instances, there may be sufficient dissolved organic matter in the water to reduce the penetration of light in the water column (Bukata et al., 1995). The decomposition of phytoplankton cells yields carbon dioxide, inorganic nitrogen, sulfur, and phosphorous compounds.

Sunlight penetrates into the water column a certain photicphotic depthdepth (the vertical distance from the water surface to the 1 percent subsurface irradiance level). Phytoplankton within the photic depth of the water column consume nutrients and convert them into organic matter via photosynthesis. This is called primary production. Zooplankton eat the phytoplankton and create organic matter. Bacterioplankton decompose this organic matter. All this conversion introduces dissolved organic matter (DOM) into oceanic, nearshore, and inland water bodies. In certain instances, there may be sufficient dissolved organic matter in the water to reduce the penetration of light in the water column (Bukata et al., 1995). The decomposition of phytoplankton cells yields carbon dioxide, inorganic nitrogen, sulfur, and phosphorous compounds.

Spectral Response of Water as a Function of Dissolved Organic Constituents

Spectral Response of Water as a Function of Spectral Response of Water as a Function of Dissolved Organic ConstituentsDissolved Organic Constituents


The more productive the phytoplankton, the greater the release of dissolved organic matter. In addition, humic substances may be produced. These often have a yellow appearance and represent an important colorant agent in the water column, which may need to be taken into consideration. These dissolved humic substances are called yellow substance or Gelbstoffe and can 1) impact the absorption and scattering of light in the water column, and 2) change the color of the water.

There are sources of dissolved organic matter other than phytoplankton. For example, the brownish-yellow color of the water in many rivers in the northern United States is due to the high concentrations of tannin from the eastern hemlock (Tsuga canadensis) and various other species of trees and plants grown in bogs in these areas (Hoffer, 1978). These tannins can create problems when remote sensing inland water bodies.

The more productive the phytoplankton, the greater the release of dissolved organic matter. In addition, humic substances may be produced. These often have a yellow appearance and represent an important colorant agent in the water column, which may need to be taken into consideration. These dissolved humic substances are called yellow substance or Gelbstoffe and can 1) impact the absorption and scattering of light in the water column, and 2) change the color of the water.

There are sources of dissolved organic matter other than phytoplankton. For example, the brownish-yellow color of the water in many rivers in the northern United States is due to the high concentrations of tannin from the eastern hemlock (Tsuga canadensis) and various other species of trees and plants grown in bogs in these areas (Hoffer, 1978). These tannins can create problems when remote sensing inland water bodies.

Spectral Response of Water as a Function of Dissolved Organic Constituents

Spectral Response of Water as a Function of Spectral Response of Water as a Function of Dissolved Organic ConstituentsDissolved Organic Constituents


GOES-East Images of the United States and Portions

of Central America on April 17, 1998

GOESGOES--East Images of the East Images of the United States and Portions United States and Portions

of Central America on of Central America on April 17, 1998April 17, 1998

GOES-East VisibleGOESGOES--East VisibleEast Visible GOES-East Thermal InfraredGOESGOES--East Thermal InfraredEast Thermal Infrared

GOES-East Water VaporGOESGOES--East Water VaporEast Water VaporJensen, 2000Jensen, 2000Jensen, 2000

Cloud Type Determination Based on Multispectral

Measurements in the Visible and Thermal Infrared

Regions of the Spectrum

Cloud Type Determination Cloud Type Determination Based on Multispectral Based on Multispectral

Measurements in the Visible Measurements in the Visible and Thermal Infrared and Thermal Infrared

Regions of the SpectrumRegions of the Spectrum

Cold

Warm

BrightDark Visible

Ther

mal

Infr

ared

tops of large convective clouds

middle level clouds or

semi-transparent high clouds

middle level convective clouds

low cumuliform clouds

landsea

Ther

mal

Infr

ared


Reflectance of Clouds and Snow in the Wavelength Interval 0.4 - 2.5 μmReflectance of Clouds and Snow in Reflectance of Clouds and Snow in

the Wavelength Interval 0.4 the Wavelength Interval 0.4 -- 2.5 2.5 μμmm


Sea-surface Temperature (SST) Maps Derived from A Three-day Composite of NOAA AVHRR Infrared Data Centered on March 4, 1999

SeaSea--surface Temperature (SST) Maps Derived from A Threesurface Temperature (SST) Maps Derived from A Three--day day Composite of NOAA AVHRR Infrared Data Centered on March 4, 1999Composite of NOAA AVHRR Infrared Data Centered on March 4, 1999

Adjusted to highlight nearshore temperature differences

Adjusted to highlightAdjusted to highlight nearshorenearshore temperature differencestemperature differences

Adjusted to highlight Gulf Stream temperature differences

Adjusted to highlight Gulf Stream Adjusted to highlight Gulf Stream temperature differencestemperature differences


Composite Sea-surface Temperature (SST) Map of

the Southeastern Bight Derived from AVHRR Data

Composite SeaComposite Sea--surface surface Temperature (SST) Map of Temperature (SST) Map of

the Southeastern Bight the Southeastern Bight Derived from AVHRR DataDerived from AVHRR Data

40

60

80

30

20

10

0

˚C

˚F


Worldwide Sea-surface Temperature (SST) Map Derived From NOAA-14 AVHRR Data

Worldwide SeaWorldwide Sea--surface Temperature (SST) Map surface Temperature (SST) Map Derived From NOAADerived From NOAA--14 AVHRR Data14 AVHRR Data

Three-day composite of thermal infrared data centered on March 4, 1999. Each pixel was allocated the highest surface temperature that occurred during the three days.

ThreeThree--day composite of thermal infrared data centered on March 4, 1999day composite of thermal infrared data centered on March 4, 1999. Each pixel . Each pixel was allocated the highest surface temperature that occurred duriwas allocated the highest surface temperature that occurred during the three days.ng the three days.


Reynolds Monthly Sea-surface Temperature (˚C) Maps Derived from

In situ Buoy and Remotely Sensed Data

Reynolds Monthly SeaReynolds Monthly Sea--surface surface Temperature (Temperature (˚̊C) Maps Derived from C) Maps Derived from

In situIn situ Buoy and Remotely Sensed DataBuoy and Remotely Sensed Data

Normal December, 1990

Normal Normal December, 1990December, 1990

La Nina December, 1988

La Nina La Nina December, 1988December, 1988

El NinoDecember, 1997

El NinoEl NinoDecember, 1997December, 1997


Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) Data Obtained on March 9, 1998

Tropical Rainfall Measurement Mission (TRMM) Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) Data Obtained on March 9, 1998Microwave Imager (TMI) Data Obtained on March 9, 1998


A passive microwave sensor that measures in five frequencies: 10.7 (45 km spatial resolution), 19.4, 21.3, 37, and 85.5 GHz (5 km spatial resolution). It has dual polarization at four of the frequencies. Swath width is 487 miles (780 km). The 10.7 GHz frequency provides a a linear response to rainfall.

A passive microwave sensor that measures in five frequencies: 10A passive microwave sensor that measures in five frequencies: 10.7 (45 km spatial resolution), 19.4, .7 (45 km spatial resolution), 19.4, 21.3, 37, and 85.5 21.3, 37, and 85.5 GHzGHz (5 km spatial resolution). It has dual polarization at four of(5 km spatial resolution). It has dual polarization at four of the frequencies. the frequencies. Swath width is 487 miles (780 km). The 10.7 Swath width is 487 miles (780 km). The 10.7 GHz GHz frequency provides a a linear response to rainfall.frequency provides a a linear response to rainfall.

Along-track cross-section of TRMM Precipitation Radar data obtained on March 9, 1998AlongAlong--track crosstrack cross--section of TRMM Precipitation Radar data obtained on March 9, 19section of TRMM Precipitation Radar data obtained on March 9, 199898

z(z(dBZdBZ))

100100 200200 300300 400400

AA

BB

Hei

ght (

km)

Hei

ght (

km)

BBAA

1010

Distance (km)Distance (km)

00 60602020 4040

55

TRMM Precipitation Radar (PR) data obtained on March 9, 1998

TRMM Precipitation Radar (PR) TRMM Precipitation Radar (PR) data obtained on March 9, 1998data obtained on March 9, 1998


Nonpoint Source Pollution Modeling Based on the Agricultural NonPoint Source (AGNPS) Pollution Water

Quality Model Applied to Two Subbasins in the Withers Swash Watershed in Myrtle beach, SC

Nonpoint Nonpoint Source Pollution Modeling Source Pollution Modeling Based on the Agricultural Based on the Agricultural NonPoint NonPoint Source (AGNPS) Pollution Water Source (AGNPS) Pollution Water

Quality Model Applied to Two Quality Model Applied to Two Subbasins Subbasins in the Withers Swash in the Withers Swash Watershed in Myrtle beach, SCWatershed in Myrtle beach, SC

Documents

Remote Sensing of WaterRemote Sensing of Wateraviris.gl.fcen.uba.ar/Curso_SR/biblio_sr/Chapter11_Water.pdfRemote Sensing of WaterRemote Sensing of Water • 74% of the Earth’s surface