Prospects for Using Prospects for Using Historical Transmissometer Data Historical Transmissometer Data

in Large-Scale Assessment of in Large-Scale Assessment of Particular Organic CarbonParticular Organic Carbon

A.V. Mishonov, W.D. Gardner, A.V. Mishonov, W.D. Gardner,

& M.J. Richardson& M.J. Richardson

Department of Oceanography, Department of Oceanography,

Texas A & M University, Texas A & M University,

College Station, TX, USA, 77843.College Station, TX, USA, 77843.

2

Data SetData Set

Transmissometer data have been collected using Transmissometer data have been collected using instruments provided by our group over the last decade in instruments provided by our group over the last decade in collaboration with WOCE, JGOFS, and other large-scale collaboration with WOCE, JGOFS, and other large-scale hydrographic programs. hydrographic programs.

These data include basin-wide transects in the North and These data include basin-wide transects in the North and South Atlantic, North and South Pacific, Indian, and South Atlantic, North and South Pacific, Indian, and Southern Oceans. Southern Oceans.

We have proposed to analyze these data and convert the We have proposed to analyze these data and convert the beam attenuation values to POC using the beam beam attenuation values to POC using the beam attenuation:POC relationships derived by our group attenuation:POC relationships derived by our group during JGOFS Process studies. during JGOFS Process studies.

3

ApproachApproach

Stramski et al. (1999, Science, 285: 239-242) have Stramski et al. (1999, Science, 285: 239-242) have introduced algorithms to estimate POC from satellite introduced algorithms to estimate POC from satellite backscatter data for the Southern Ocean for both surface backscatter data for the Southern Ocean for both surface values and euphotic zone integrations. values and euphotic zone integrations.

In a similar manner, our basin-wide data will be compared In a similar manner, our basin-wide data will be compared with satellite backscattering data on appropriate seasonal with satellite backscattering data on appropriate seasonal and space scales to establish region-specific algorithms. and space scales to establish region-specific algorithms.

A compilation of historic hydrographic/optical data has A compilation of historic hydrographic/optical data has been compared by season with recent satellite data by been compared by season with recent satellite data by Mishonov et al. (1999, IUGG-99, Vol. B., p. 242) and the Mishonov et al. (1999, IUGG-99, Vol. B., p. 242) and the results further validate our proposed global synthesis of results further validate our proposed global synthesis of POC in Case I waters (non-coastal) using satellite-derived POC in Case I waters (non-coastal) using satellite-derived data.data.

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Comparison of SeaWiFS &Comparison of SeaWiFS & in-situ in-situ SamplingSampling

Data: 37Data: 37thth cruise of cruise of RV RV Academician Academician

Vernadsky,Vernadsky, Aug - Sep 1988Aug - Sep 1988

-60 -50 -40 -30

0

10

0

10

-60 -50 -40 -30

0

10

0

10

Sep’98Sep’98

SeaWiFS chlorophyllSeaWiFS chlorophyll

-50 -40 -30

0

10

-50 -40 -30

0

10

Dominant WavelengthDominant Wavelength

-50 -40 -30

0

10

-50 -40 -30

0

10

Forele-Ule ScaleForele-Ule Scale

-50 -40 -30

0

10

-50 -40 -30

0

10

Secchi DiskSecchi Disk

-50 -40 -30

0

10

-50 -40 -30

0

10

Chlorophyll-aChlorophyll-a

Calculated by regression

Sep’98Sep’98Data fromData fromData fromData from

5

-60 -50 -40 -30

0

10

-60 -50 -40 -30

0

10

-60 -50 -40

0

10

-60 -50 -40

0

10

Dominant Dominant WavelengthWavelength

-60 -50 -40

0

10

-60 -50 -40

0

10

Chlorophyll-aChlorophyll-a

-60 -50 -40

0

10

-60 -50 -40

0

10

Forele-UleForele-UleScaleScale

-60 -50 -40

0

10

-60 -50 -40

0

10

Secchi DiskSecchi Disk

Feb’98Feb’98

SeaWiFS chlorophyllSeaWiFS chlorophyll

Data: 41Data: 41stst cruise of cruise ofRV RV Academician Academician

Vernadsky,Vernadsky,Feb - May 1990Feb - May 1990

Feb’98Feb’98 Data fromData fromData fromData from

Comparison of SeaWiFS &Comparison of SeaWiFS & in-situ in-situ SamplingSampling

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Initial Data SetInitial Data Set

15 cruises from February 1992 till June 1997;15 cruises from February 1992 till June 1997; 2027 Stations in Pacific, Indian and Atlantic 2027 Stations in Pacific, Indian and Atlantic

oceans;oceans; 1817 Transmissometer Casts;1817 Transmissometer Casts; Accompanied hydrological data on Accompanied hydrological data on

Temperature, Salinity and Dissolved Oxygen;Temperature, Salinity and Dissolved Oxygen; More data will be added from JGOFS, SAVE, More data will be added from JGOFS, SAVE,

WOCE, etc. legs. WOCE, etc. legs.

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Partial WOCE Cruise Partial WOCE Cruise ListList

TermsWOCE Line Ship name

Start Finishs04p Akademik IOFFE 22-Feb-92 29-Mar-92p14c Knorr 01-Sep-92 13-Sep-92

p16a/ p17a Knorr 08-Oct-92 24-Nov-92p17e/ p19s Knorr 14-Dec-92 18-Jan-93

p19c Knorr 23-Feb-93 10-Apr-93p17n Th. Thompson 16-May-93 26-Jun-93p14n Th. Thompson 07-Jul-93 29-Aug-93i09s Knorr 24-Jan-95 05-Mar-95

i05e/ i08n Knorr 10-Mar-95 15-Apr-95i03 Knorr 24-Apr-95 05-Jun-95

i04 / i05w / i07c Knorr 11-Jun-95 11-Jul-95i07n Knorr 15-Jul-95 24-Aug-95i10 Knorr 11-Nov-95 24-Nov-95s04i N. Palmer 03-May-96 02-Jul-96

ACCE-A24 Knorr 30-May-97 28-Jun-97

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Station Coverage:Station Coverage: WOCE, JGOFS & other WOCE, JGOFS & other datadata

Loaded Loaded Not loadedNot loaded

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Transmissometer Data SetTransmissometer Data Set

73

153

323

125

207

456

203183

68 54

133

49

050100150200250300350400450500

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Monthly DistributionMonthly Distribution

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Pacific Ocean Pacific Ocean SectionSection

Th.Thompson,Th.Thompson, Jul-Aug.93, p14n line Jul-Aug.93, p14n line

0 500 1000 1500 2000 2500 3000 3500 4000

-6000

-5000

-4000

-3000

-2000

-1000

0

0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95

0 500 1000 1500 2000 2500 3000 3500 4000

-6000

-5000

-4000

-3000

-2000

-1000

0

0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95

Beam AttenuationBeam Attenuation

Distance, nmDep

th, m

SouthSouthNorthNorth

0 500 1000 1500 2000 2500 3000 3500 4000-500

-400

-300

-200

-100

0

-500

-400

-300

-200

-100

0

357911131517192123252729

33.0

33.5

34.0

34.5

35.0

35.5

36.0

180°185°

-10°0°10°20°30°40°50°

AVHRR SSTAVHRR SSTJuly 1993July 1993

Data fromData fromData fromData from

t, °Ct, °C

S, p.s.u.S, p.s.u. Stations PositionStations Position

TemperatureTemperature

SalinitySalinity

Upper 500 metersUpper 500 meters

Pacific Ocean Pacific Ocean SectionSectionTh.Thompson,Th.Thompson, Jul-Aug.93, p14n Jul-Aug.93, p14n lineline

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0 500 1000 1500 2000 2500 3000 3500 4000-500

-400

-300

-200

-100

0

-500

-400

-300

-200

-100

0

2 1

2 2

2 3

2 4

2 5

2 6

2 70 . 3 8

0 . 4 8

0 . 5 8

0 . 6 8

0 . 7 8

180°185°

-10°0°10°20°30°40°50°

SeaWiFS CHLSeaWiFS CHLJuly 1998July 1998

Data fromData fromData fromData from

Kg/mKg/m33

CC m m-1-1

Stations PositionStations Position

DensityDensity

Beam AttenuationBeam Attenuation

Upper 500 metersUpper 500 meters

Pacific Ocean Pacific Ocean SectionSectionTh.Thompson,Th.Thompson, Jul-Aug.93, p14n line Jul-Aug.93, p14n line

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Indian Ocean Indian Ocean Section Section

KnorrKnorr, Feb. 95, i09s line, Feb. 95, i09s line

90°E

95°E

-30° -25° -20° -15° -10° -5° 0° 5° 10° 15° 20°

0 500 1000 1500 2000 2500 3000

-6000

-5000

-4000

-3000

-2000

-1000

0

0.38 0.40 0.42 0.44 0.46 0.48 0.50 0.52 0.54 0.56Distance, nm

Dep

th, m

Beam AttenuationBeam Attenuation

NNSS

Stations Stations PositionPosition

0 500 1000 1500 2000 2500 3000

-400

-200

0

9

11

13

15

17

19

21

23

25

27

29

-400

-200

0

32

32

33

33

34

34

35

35

36

36AVHRR SSTAVHRR SST

Feb 1995Feb 1995t, °Ct, °CS, p.s.u.S, p.s.u.

Stations PositionStations Position

TemperatureTemperature

SalinitySalinity

Upper 500 metersUpper 500 meters

Indian Ocean Indian Ocean Section Section

KnorrKnorr, Feb. 95, i09s line, Feb. 95, i09s line

Data Data fromfromData Data fromfrom

NorthNorth

90°E

95°E

-30° -25° -20° -15° -10° -5° 0° 5° 10° 15° 20°

90°E

95°E

-30° -25° -20° -15° -10° -5° 0° 5° 10° 15° 20°

0 500 1000 1500 2000 2500 3000

-400

-200

0

21

22

23

24

25

26

27

-400

-200

0

0.40

0.45

0.50

0.55

SeaWiFS CHLSeaWiFS CHLFeb, 1998Feb, 1998

Stations PositionStations Position

Upper 500 metersUpper 500 meters

Indian Ocean Indian Ocean Section Section

KnorrKnorr, Feb. 95, i09s line, Feb. 95, i09s line

Data Data fromfromData Data fromfrom

Density Density

Beam AttenuationBeam AttenuationCC m m

-1-1

NorthNorth

Kg/mKg/m33

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Future plans: 1Future plans: 1

Transmissometer database: Transmissometer database: – Process 17 WOCE cruises of transmissometer Process 17 WOCE cruises of transmissometer

data;data;– Add processed transmissometer & POC data from Add processed transmissometer & POC data from

19 JGOFS cruises;19 JGOFS cruises;– Add processed transmissometer data from other Add processed transmissometer data from other

basin-scale cruises where we have data (9basin-scale cruises where we have data (9++).). Beam attenuation / POC relationship:Beam attenuation / POC relationship:

– Use algorithms developed during JGOFS, NABE, Use algorithms developed during JGOFS, NABE, EqPAC, Indian Ocean and Southern Ocean EqPAC, Indian Ocean and Southern Ocean expeditions;expeditions;

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Future plans: 2Future plans: 2

Compile SeaWiFS back-scatter data for Compile SeaWiFS back-scatter data for comparable times of POC + Beam attenuation comparable times of POC + Beam attenuation measurements; measurements;

Refine algorithms for predicting POC from Refine algorithms for predicting POC from SeaWiFS data;SeaWiFS data;

Examine hydrography of each area:Examine hydrography of each area:– Mixed layer depth;Mixed layer depth;– Subsurface maxima.Subsurface maxima.

Correlate POC standing stock by ocean basin & Correlate POC standing stock by ocean basin & season;season;

Analyse data in context of JGOFS Synthesis & Analyse data in context of JGOFS Synthesis & Modelling Program.Modelling Program.

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Thank You!Thank You!