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Remote sensing application for Remote sensing application for monitoring and assessment of monitoring and assessment of
eutrophicationeutrophicationin the NOWPAP regionin the NOWPAP region
JojiJoji IshizakaIshizaka(Nagasaki University)(Nagasaki University)
OutlineOutline
•• Definition and Consequence of Definition and Consequence of EutrophicationEutrophication
•• Toyama BayToyama Bay•• South Sea of Korea Red TideSouth Sea of Korea Red Tide•• East China Sea and Yellow SeaEast China Sea and Yellow Sea•• AriakeAriake Bay Red TideBay Red Tide
Definition of EutrophicationDefinition of Eutrophication
•• Accumulation of nutrients and organic Accumulation of nutrients and organic matter to lake and coastal environments matter to lake and coastal environments and resulted changes of ecosystem.and resulted changes of ecosystem.
•• Natural: Long term succession.Natural: Long term succession.
•• Anthropogenic (HumanAnthropogenic (Human--made): Discharge made): Discharge of waist, fertilizer etc. of waist, fertilizer etc.
2
Consequence of EutrophicationConsequence of Eutrophication
•• Increase of Red Tide (HAB: harmful algal Increase of Red Tide (HAB: harmful algal bloom)bloom)
•• Decrease of Low Dissolved Oxygen Decrease of Low Dissolved Oxygen ConditionCondition
•• Mass Mortality to OrganismsMass Mortality to Organisms
BottomBottom--up Control up Control ((vs. Topvs. Top--down Control)down Control)
Fish YieldFish Yield
⇑⇑Ecosystem Structure (Ecosystem Structure (trophictrophic level)level)
⇑⇑Primary ProductionPrimary Production
⇑⇑Environments Environments (Nutrients)(Nutrients)
Food Food ChainChain
Lalli and Parsons
3
Global CHLGlobal CHL--aaMost of the ocean is Most of the ocean is oligotrophicoligotrophic!!
Paradox of EutrophicationParadox of Eutrophication
•• Phytoplankton: Primary ProducerPhytoplankton: Primary ProducerOligotrophicOligotrophic Environment Environment –– Low ProductivityLow Productivity
•• Large Area is Large Area is OligotrophicOligotrophicFishing Ground Fishing Ground –– Upwelling Area (Natural Upwelling Area (Natural
Eutrophication)Eutrophication)
Appropriate Amount of Nutrient is Appropriate Amount of Nutrient is Necessary!Necessary!
What is Appropriate Amount?What is Appropriate Amount?
BeforeBefore EutrophicationEutrophication
OrganicMaterials
NutrientsFishingHarvest
OrganicMaterials
Nutrients Phytoplankton
Zooplankton Fish/Clam
NutrientsOrganic
Materials
Sedimentation
4
After Artificial EutrophicationAfter Artificial Eutrophication
OrganicMaterials
FishingHarvest
Nutrients Phytoplankton
Zooplankton
Fish/Clam
NutrientsOrganic
Materials
Sedimentation
Human Pollution
OxygenDepletion
Red Tide
Blue Tide
How we can use remote sensing to How we can use remote sensing to monitoring of eutrophication.monitoring of eutrophication.
•• Direct observation of changeDirect observation of change•• Check of appropriate location of ship Check of appropriate location of ship
observationobservation•• Check of background level Check of background level
•• -- chlorophyllchlorophyll--a, red tidea, red tide•• -- SST, altimeter,,SST, altimeter,,
Toyama Bay ProjectToyama Bay ProjectMonitoring in situ Survey of Toyama BayMonitoring in situ Survey of Toyama Bay–– Observed Variable with VesselObserved Variable with Vessel
Temperature, Salinity, Water Color,Temperature, Salinity, Water Color,Transparency, Remote Sensing ReflectanceTransparency, Remote Sensing Reflectance
–– Analyzed Variable in LabAnalyzed Variable in LabDissolved Oxygen, CODDissolved Oxygen, CODPhosphate, Nitrogen and SilicatePhosphate, Nitrogen and SilicateChlChl--a, Suspended Solid, CDOM, a, Suspended Solid, CDOM,
5
Analysis of MODIS Analysis of MODIS ChlChl--a Daily Imagesa Daily Images
Anti-clockwise flow pattern
Monthly Monthly SeaWiFSSeaWiFS ChlChl--a a Data Data AanalysisAanalysis (98(98--03)03)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
1998
1999
2000
2001
2002No valide dataavailable
2003
Two peaks of Chl-a concentration one in early spring and the other in fall every year
Chl-a concentration of inner are of the Bay become higher every summer
Seasonal Variability Seasonal Variability of Satellite of Satellite Chlorophyll a Chlorophyll a
1997~20021997~2002
Chlorophyll a Chlorophyll a >> 0.8 0.8 μμg lg l--11
(Yamada et al.)
6
Seasonal variability of Seasonal variability of SeaWiFSSeaWiFS Chl.aChl.a from each from each sampling pointssampling points
Outer
Inner
Middle
InterInter--annual Variation annual Variation of Coastal of Coastal SeaWiFSSeaWiFSChlChl--a Concentration a Concentration
(98(98--03)03)
1998 1999 2000 2001 2002 2003
Validation of Validation of SeaWiFSSeaWiFS DataData
7
Strong positive correlation(R = 0.87, N =86)
Less variability was found in spring and summer.
Comparison of in situ Comparison of in situ ChlChl--a and a and COD (Chemical Oxygen Demand)COD (Chemical Oxygen Demand)
Transport ofC. Polykrikoides
Red Tide?(MODIS, JAXA)
3. Results and Discussions
(a)
(b)
(c)
(d)
(e)
Aug. 19, 2002 Sep. 8 , 2002 True Color from MODIS bands (645, 555,469 nm).
MODIS Chlorophyll Con.
1. 10 sub-samples collected from various water condition based on true color and chlorophyll images
(NFRDI, 2004)(Son, Y.B. et al., In prep.)
8
3. Results and Discussions : Spectral characteristic of sub-samples
Bright color (B1, B2) : Radiance peaks at green band.High radiance and particulate backscattering but phytoplankton absorption is minimal
High chlorophyll and red tide (H, R) : Radiance peaks at green band High absorption of the phytoplankton and gelbstoff/detritus .
Particulate backscattering values are ~3-4 times lower than in bright color samples.Low and moderate chlorophyll (L, M) : Radiance peaks from 412 nm to 531 nm (blue to green bands)
absorption and backscattering of the phytoplankton, gelbstoff, and detritus in all visual wavelengths
3. Results and Discussions : Scheme for identifying the water types
667 nm >678 nm
Turbid Water Mixed Water
Highest peak at 412 nm
Red Tide
Clear Water
Intermediate Water
No values at748 and 869 nm
Yes No
Yes
Yes
Yes
Step 1Step 3
Step 4-2
Step 4-3
Step 2-1
Step 2-2
Max(531 & 551 nm)
Radiance ratio of 412/443 is greater than that of 531/551
Step 4-1
Highest peak at 551 nm
Radiance ratio of 412/488 is greater than that of 531/551
Step 2
No
No
No
Step 4
Yes
Yes
Yes
No
No
No
Step 1: The maximum peaks in blue-to-green wavelengths to separate largely two different water types.Step 2: Determining intermediate and clear waters.
step 2-1 used the highest peak at nLw(412). Step 2-2 used that the values of nLw(748) and nLw(869) are zero.
Step 3: Turbid and mixed waters included red tide water. Turbid water used nLw(667) > nLw(678) and mixed water as nLw(667) < nLw(678).
3. Results and Discussions : Identify the water types
LC CW IW TW MW LC CW IW TW MW
19% 81%
72%
9%3%
16%
44%56%
1%
43%33%
23%
Aug. 19, 2002 Sep. 8, 2002
Step 1 Step 1
Step 2
Step 2
Step 2
Step 2
Step 3:nLw(667)>nLw(678)
Step 3:nLw(667)<nLw(678)
Step 3:nLw(667)>nLw(678)
Step 3:nLw(667)<nLw(678)
9
3. Results and Discussions : HABs DetectionSep. 8, 2002Aug. 19, 2002
Step 4-1 : nLw(551) is highest peak among The 9 visible bands of MODIS
Step 4-2 :
Step 4-3 :
(NFRDI, 2004)(NFRDI, 2004)
Increase Increase of China of China Coastal Coastal Area in Area in the East the East China China SeaSea
((Zhu, Zhu, 20032003))
Jan Feb Mar Apr
AugMay June July
Sep Oct Nov Dec
10-year average Chl-a
10
Jan Feb Mar Apr
May June July Aug
Sep Oct Nov Dec
10-year average nLw555 (Sediment)
High High chl.achl.a area and area and Low Salinity WaterLow Salinity Water
(Kim et al., Submitted)
Distribution of month of maximumDistribution of month of maximum
11
Distribution of month of maximumDistribution of month of maximum
浙江
省
長江
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10JFMAMJJASOND02468
10JFMAMJJASOND
02468
10
JFMAMJJASOND02468
10JFMAMJJASOND
02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10JFMAMJJASOND
02468
10
Seasonal Changes in Each AreaSeasonal Changes in Each Area
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10 Area 4
JFMAMJJASOND02468
10 Area 5JFMAMJJASOND
02468
10JFMAMJJASOND
02468
10
JFMAMJJASOND02468
10JFMAMJJASOND
02468
10 Area 9
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10 Area 11
JFMAMJJASOND02468
10 Area 12
JFMAMJJASOND02468
10 Area 13
JFMAMJJASOND02468
10 Area 14
JFMAMJJASOND02468
10 Area 15JFMAMJJASOND
02468
10 Area 16
浙江
省
長江
Changjiang Diluted Water
(Yamaguchi et al., In prep.)
12
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10 Area 4
JFMAMJJASOND02468
10 Area 5JFMAMJJASOND
02468
10JFMAMJJASOND
02468
10
JFMAMJJASOND02468
10JFMAMJJASOND
02468
10 Area 9
JFMAMJJASOND02468
10
JFMAMJJASOND02468
10 Area 11
JFMAMJJASOND02468
10 Area 12
JFMAMJJASOND02468
10 Area 13
JFMAMJJASOND02468
10 Area 14
JFMAMJJASOND02468
10 Area 15JFMAMJJASOND
02468
10 Area 16
浙江
省
長江
Changjiang Diluted Water
Interannual Variability of Chl-a and Changjiang Discharge on May-Oct.
0x100 2x104 4x104 6x104 8x10402468
1012
0x100 2x104 4x104 6x104 8x1040
0.20.40.60.8
11.2
0x100 2x104 4x104 6x104 8x1040
1
2
3
4
0x100 2x104 4x104 6x104 8x1040
1
2
3
4
0x100 2x104 4x104 6x104 8x1040
0.20.40.60.8
11.21.4
R=0.27P=0.12
R=0.43P<0.01
R=0.57P<0.01
R=0.67P<0.01
(Lag= 0)
(Lag= 0)
(Lag= 1)
(Lag= 2)
R=0.70P<0.01
(Lag= 2)
CRD (m3/s)
chl-a
(mg/
m3 )
Correlation between Chl-a and Discharge with Lag 0-2 months
13
Interannual Variability in the Yellow Sea
ChangjiangDischarge
Chl.a ○
nLw555
Spring Summer
Increase of Frequency of Intense Increase of Frequency of Intense Algal Blooms in the Yellow SeaAlgal Blooms in the Yellow Sea
Nutrient Changes in the Yellow SeaNutrient Changes in the Yellow Sea
14
YOC Verification ProjectYOC Verification Project((Yellow Sea Large Marine Yellow Sea Large Marine
EcosystemEcosystem-- Ocean Color ProjectOcean Color Project))
Standard_chlorophyll_concentration
New_chlorophyll_concentration
15
Location Location of the of the Ariake Ariake SoundSound
50
40
30
20
120 130 140 150
129.5 130.0 130.5 131.0
33.5
33.0
32.5
32.0
Isahaya Bay
Reclamation Area1996~
Eutrophication in Eutrophication in AriakeAriake Bay?Bay?
-- Symptom of eutrophicationSymptom of eutrophication•• Red tide increaseRed tide increase•• Low oxygen conditionLow oxygen condition
However:However:•• No nutrient load increaseNo nutrient load increase•• Dike Construction on 1998Dike Construction on 1998
諫早湾干拓(諫早湾干拓(ASTERASTER))
16
IsahayaIsahaya DikeDike
Red Tide in Ariake Bay in Winter 2000Red Tide in Ariake Bay in Winter 2000--0101NoriNori (red algae) Culture(red algae) Culture40% ($200M!) Loss40% ($200M!) Loss
Comparison with Red Tide Map Comparison with Red Tide Map Produced by Nagasaki Fisheries Produced by Nagasaki Fisheries Experimental StationExperimental Station
:Observed Area)(
有明海
Nov. 9-Dec. 6, 2001
July 8-13, 2001有明海
Jul 9,2001
Nov 22,2001
17
RelcamationArea
Red Red TideTidein in AriakeAriakeBayBay
SeaWiFS (2000.11.23SeaWiFS (2000.11.23--2001.4.1)2001.4.1)
0404
0303
0202
0101
0000
9999
9898
121211111010998877665544332211
Monthly SeaWiFS Chl.a 0.01 0.1 10 64
18
Turbidity and Turbidity and Chlorophyll Chlorophyll Change with Change with Tidal CycleTidal Cycle
SEA
LEVEL
(cm
)
6410
1
0.050.1
31
0.10.05
3 5 9 10 11 14 16 24
5
October, 2002
700600500400300200100
SpringNeapSpring
Chl
.anL
w 5
55
Chl.a
(m
g m
-3) n
Lw
555
(mW
cm-2
μm
-1 sr
-1)
48
1216
1.01.52.02.53.020
(SeaWiFS)
Red Tide Red Tide Number Number in in AriakeAriakeSoundSound((IsobeIsobe,,20002000))
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00
3030--year Increase of transparencyyear Increase of transparencyValue (m) % Change
19
AriakeAriake Bay HypothesisBay Hypothesis
•• Decrease of Tidal Flat (Not only Decrease of Tidal Flat (Not only IsahayaIsahayaBay)Bay)
•• Decrease of Tidal CurrentDecrease of Tidal Current•• Decrease of TransparencyDecrease of Transparency•• Increase of Available Light to Increase of Available Light to
PhytoplanktonPhytoplankton•• Increase of Red TideIncrease of Red Tide•• Increase of Low Oxygen WaterIncrease of Low Oxygen Water• D f ClDec ease of Clam
Use of Remote Sensing for Use of Remote Sensing for EutrophicationEutrophication MonitoringMonitoring
•• Large Spatial CoverageLarge Spatial Coverage•• High FrequencyHigh Frequency•• Low PriceLow Price
HoweverHowever•• Period is still limited for 10 years.Period is still limited for 10 years.•• Accuracy have to be checked.Accuracy have to be checked.•• Cause and effect is not clear.Cause and effect is not clear.
•• Combination with shipCombination with ship--observation is necessary.observation is necessary.