Carolina Distinguished Professor Department of Geography University of South Carolina

Carolina Distinguished ProfessorCarolina Distinguished ProfessorDepartment of GeographyDepartment of Geography

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

[email protected]@sc.edu

Carolina Distinguished ProfessorCarolina Distinguished ProfessorDepartment of GeographyDepartment of Geography

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

[email protected]@sc.edu

Remote Sensing of WaterRemote Sensing of WaterRemote Sensing of WaterRemote Sensing of Water

•• 74% of the Earth’s surface is water74% of the Earth’s surface is water•• 97% of the Earth’s volume of water is in the saline oceans97% of the Earth’s 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%)

•• 74% of the Earth’s surface is water74% of the Earth’s surface is water•• 97% of the Earth’s volume of water is in the saline oceans97% of the Earth’s 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 PlanetEarth: The Water Planet

Jensen, 2000Jensen, 2000Jensen, 2000Jensen, 2000

The total radiance, (The total radiance, (LLtt) recorded by a remote sensing system over a waterbody is a ) recorded by a remote sensing system over a waterbody is a

function of the electromagnetic energy from four sources:function of the electromagnetic energy from four sources:

LLtt = L = Lpp + L + Lss + L + Lvv + L + Lbb

•• LLpp is the the radiance recorded by a sensor resulting from the downwelling solar (E is the the radiance recorded by a sensor resulting from the downwelling solar (E sunsun) )

and sky (Eand sky (Eskysky) 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 air-water interface is the radiance that reaches the air-water interface ((free-surface layerfree-surface layer or or boundary boundary

layerlayer) but only penetrates it a millimeter or so and is then reflected from the water ) 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 surface. This reflected energy contains spectral information about the near-surface characteristics of the water.characteristics of the water.

•• LLvv is the radiance that penetrates the air-water interface, interacts with the 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 organic/inorganic constituents in the water, and then exits the 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 water columninformation about the internal bulk characteristics of the water column

•• LLbb is the radiance that reaches the is the radiance that reaches the bottombottom of the waterbody, is reflected from it and of the waterbody, is reflected from it and

propagates back through the water column, and then exits the water column. This 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). radiance is of value if we want information about the bottom (e.g., depth, color).












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


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 radiance

LLss = free-surface layer = free-surface layer

reflectancereflectance

LLvv = subsurface volumetric = subsurface volumetric


LLbb = bottom reflectance= 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 radiance

LLss = free-surface layer = free-surface layer


LLvv = subsurface volumetric = subsurface volumetric


LLbb = bottom reflectance= bottom reflectanceJensen, 2000Jensen, 2000Jensen, 2000Jensen, 2000























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


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

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

Black and white infrared photograph Black and white infrared photograph of water bodies in Floridaof 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 Black and white infrared photograph with sunglintphotograph with sunglint

Black and white infrared Black and white infrared photograph with sunglintphotograph with sunglint


AbsorptionAbsorption and and Scattering Scattering

Attenuation in Pure Attenuation in Pure WaterWater

AbsorptionAbsorption and and Scattering Scattering


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

Molecular water Molecular water absorptionabsorption dominates in the ultraviolet dominates in the ultraviolet (<400 nm) and in the yellow (<400 nm) and in the yellow through the near-infrared through the near-infrared portion of the spectrum (>580 portion of the spectrum (>580 nm). Almost all of the nm). Almost all of the incident near-infrared and incident near-infrared and middle-infrared (740 - 2500 middle-infrared (740 - 2500 nm) radiant flux entering a nm) 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 Absorption and ScatteringScattering


Absorption and Absorption and ScatteringScattering


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 - 500 nm). the spectrum (400 - 500 nm). 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 near-infrared yellow through near-infrared regions because the attenuation regions because the attenuation is so great.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 - 500 nm). the spectrum (400 - 500 nm). 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 near-infrared yellow through near-infrared regions because the attenuation regions because the attenuation is so great.is so great.


The best wavelength region for discriminating land from pure The best wavelength region for discriminating land from pure water is in the near-infrared and middle-infrared from water is in the near-infrared and middle-infrared from 740 - 2,500740 - 2,500 nmnm. .

In the near- and middle-infrared regions, water bodies appear In the near- and middle-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.

The best wavelength region for discriminating land from pure The best wavelength region for discriminating land from pure water is in the near-infrared and middle-infrared from water is in the near-infrared and middle-infrared from 740 - 2,500740 - 2,500 nmnm. .

In the near- and middle-infrared regions, water bodies appear In the near- and middle-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 BodiesMonitoring the Surface Extent of Water Bodies


Water PenetrationWater PenetrationWater PenetrationWater Penetration

SPOT Band 1 (0.5 - 0.59 SPOT Band 1 (0.5 - 0.59 m) m) greengreenSPOT Band 1 (0.5 - 0.59 SPOT Band 1 (0.5 - 0.59 m) m) greengreen SPOT Band 2 (0.61 - 0.68 SPOT Band 2 (0.61 - 0.68 m) m) redredSPOT Band 2 (0.61 - 0.68 SPOT Band 2 (0.61 - 0.68 m) m) redred SPOT Band 3 (0.79 - 0.89 SPOT Band 3 (0.79 - 0.89 m) m) NIRNIRSPOT Band 3 (0.79 - 0.89 SPOT Band 3 (0.79 - 0.89 m) m) NIRNIR

Palancar ReefPalancar Reef Caribbean SeaCaribbean Sea

Cozumel IslandCozumel Island


When conducting water-quality studies using remotely sensed data, we are usually When conducting water-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 radiant energy are a water column toward the sensor. The characteristics of this radiant 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 ), and the total amount of absorption and scattering attenuation that takes place in the water total amount of absorption and scattering attenuation that takes place in the water

column due to each of these constituents, column due to each of these constituents, c(c())::

LLvv = f = f [[wwc(c()), SM, SMc(c()), Chl, Chlc(c()), w, wc(c()) ].].

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

When conducting water-quality studies using remotely sensed data, we are usually When conducting water-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 radiant energy are a water column toward the sensor. The characteristics of this radiant 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 ), and the total amount of absorption and scattering attenuation that takes place in the water total amount of absorption and scattering attenuation that takes place in the water

column due to each of these constituents, column due to each of these constituents, c(c())::

LLvv = f = f [[wwc(c()), SM, SMc(c()), Chl, Chlc(c()), w, wc(c()) ].].

It is useful to look at the effect that each of these constituents has on the spectral It is useful to look at the effect that each of these constituents 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 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

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 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 - 4 range from fine clay particles ( 3 - 4 m in diameter), to silt m in diameter), to silt (5 - 40 (5 - 40 m), to fine-grain sand (41 - 130 m), to fine-grain sand (41 - 130 m), and coarse grain m), and coarse grain sand (131 - 1250 sand (131 - 1250 m). 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 nearshore water sediment is concentrated in the inland and nearshore 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 m in diameter. m 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 - 4 range from fine clay particles ( 3 - 4 m in diameter), to silt m in diameter), to silt (5 - 40 (5 - 40 m), to fine-grain sand (41 - 130 m), to fine-grain sand (41 - 130 m), and coarse grain m), and coarse grain sand (131 - 1250 sand (131 - 1250 m). 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 nearshore water sediment is concentrated in the inland and nearshore 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 m in diameter. m in diameter.

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

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 #51STS #51


Secchi DiskSecchi DiskSecchi DiskSecchi Disk

Used to measure Used to measure suspended sediment suspended sediment

in water bodiesin water bodies

Used to measure Used to measure suspended sediment suspended sediment

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

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

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

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

90 cm165 cm15˚Spectroradiometer35 cm diameterwatersurface

diameter = 3.66 m 90 cm165 cm15˚Spectroradiometer35 cm diameterwatersurface

diameter = 3.66 m

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

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

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

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

clayclayclayclay

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

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

PlanktonPlankton is the generic term used to describe all the living organisms (plant is the generic term used to describe all the living organisms (plant and animal) present in a waterbody that cannot resist the current (unlike and animal) present in a waterbody that cannot resist the current (unlike fish). Plankton may be subdivided further into algal plant organisms fish). Plankton may be subdivided further into algal plant organisms ((phytoplanktonphytoplankton), animal organisms (), animal organisms (zoolanktonzoolankton), bacteria (), bacteria (bacterio-bacterio-planktonplankton), and lower platn forms such as ), and lower platn forms such as algal fungialgal fungi. . PhytoplanktonPhytoplankton are are small single-celled plants smaller than the size of a pinhead. Phytoplankton, small single-celled plants smaller than the size of a pinhead. Phytoplankton, like plants on land, are composed of substances that contain carbon. 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 sink to the ocean or water-body floor when they die. All phytoplankton in water bodies contain the photosynthetically active phytoplankton in water bodies contain the photosynthetically active pigment pigment chlorpohyll achlorpohyll a. There are two other phytoplankton . There are two other phytoplankton photosynthesizing agents: carotenoids and phycobilins. Bukata et al (1995) photosynthesizing agents: carotenoids and phycobilins. Bukata et al (1995) suggest, however, that suggest, however, that chlorphyll achlorphyll a 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 Spectral Response of Water as a Function of Organic Constituents - PlanktonOrganic Constituents - Plankton

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


Micrograph of A Micrograph of A Photosynthesizing DiatomPhotosynthesizing Diatom

Micrograph of A Micrograph of A Photosynthesizing DiatomPhotosynthesizing Diatom

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

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

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

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

chloroplastmaterial

cell wallchloroplast

materialcell wall


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

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

Percent reflectance of clear and Percent reflectance of clear and algae-laden water based onalgae-laden water based on in situ in 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 nm and strong 400 and 500 nm and strong chlorophyll achlorophyll a absorption of red light absorption of red light at approximately 675 nmat approximately 675 nm

Percent reflectance of clear and Percent reflectance of clear and algae-laden water based onalgae-laden water based on in situ in 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 nm and strong 400 and 500 nm and strong chlorophyll achlorophyll a absorption of red light absorption of red light at approximately 675 nmat approximately 675 nm

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

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

Perc

ent R

efle

ctan

cePe

rcen

t Ref

lect

ance

Chlorophyll in Ocean WaterChlorophyll in Ocean WaterChlorophyll in Ocean WaterChlorophyll in Ocean Water

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

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

ChlChl = x [ = x [L(L(11)/L()/L(22))]]yy

Where Where L(L(11)) and and L(L(22)) are the upwelling radiances at selected wavelengths are the upwelling radiances at selected wavelengths

recorded by the remote sensing system and recorded by the 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 ratios of The most important SeaWiFS algorithms involve the use of band ratios of 443/355 nm and 490/555 nm. 443/355 nm and 490/555 nm.

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

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

ChlChl = x [ = x [L(L(11)/L()/L(22))]]yy

Where Where L(L(11)) and and L(L(22)) are the upwelling radiances at selected wavelengths are the upwelling radiances at selected wavelengths

recorded by the remote sensing system and recorded by the 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 ratios of The most important SeaWiFS algorithms involve the use of band ratios of 443/355 nm and 490/555 nm. 443/355 nm and 490/555 nm.

Global 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

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

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

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

derived from SeaWiFS dataderived 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, 2000Jensen, 2000

Sunlight penetrates into the water column a certain photic depthphotic 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 photic depthphotic 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.

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.




GOES-East Images of the GOES-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 Images of the GOES-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 VisibleGOES-East VisibleGOES-East VisibleGOES-East Visible GOES-East Thermal InfraredGOES-East Thermal InfraredGOES-East Thermal InfraredGOES-East Thermal Infrared

GOES-East Water VaporGOES-East Water VaporGOES-East Water VaporGOES-East Water VaporJensen, 2000Jensen, 2000Jensen, 2000Jensen, 2000

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

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

The

rmal

Inf

rare

d


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


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

Sea-surface Temperature (SST) Maps Derived from A Three-day Sea-surface Temperature (SST) Maps Derived from A Three-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 Adjusted to highlight nearshore temperature differencestemperature differences

Adjusted to highlight nearshore Adjusted to highlight nearshore temperature differencestemperature differences

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

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


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

Southeastern Bight Derived Southeastern Bight Derived from AVHRR Datafrom AVHRR Data

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

Southeastern Bight Derived Southeastern Bight Derived from AVHRR Datafrom AVHRR Data


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

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

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

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


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

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

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

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

Normal Normal December, 1990December, 1990

Normal Normal December, 1990December, 1990

La Nina La Nina December, 1988December, 1988

La Nina La Nina December, 1988December, 1988

El NinoEl Nino December, 1997December, 1997

El NinoEl Nino December, 1997December, 1997


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

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, 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. 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.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: 10.7 (45 km spatial resolution), 19.4, 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. 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.Swath width is 487 miles (780 km). The 10.7 GHz frequency provides a a linear response to rainfall.

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

z(dBZ)z(dBZ)

100100 200200 300300 400400

AA

BB

Hei

ght

(km

)H

eigh

t (k

m)

BBAA

1010

Distance (km)Distance (km)

00 60602020 4040

55

TRMM Precipitation Radar (PR) TRMM Precipitation Radar (PR) data obtained on March 9, 1998data 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 Nonpoint Source Pollution Modeling Based on the Agricultural NonPoint Based on the Agricultural NonPoint Source (AGNPS) Pollution Water Source (AGNPS) Pollution Water

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

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

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

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Carolina Distinguished Professor Department of Geography University of South Carolina