Time-series station in the NW subarctic Pacific ST

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Time-series station in the NW subarctic Pacific ST Powered By Docstoc
					            Time-series station in the NW subarctic Pacific:
                ST. KNOT 44N, 155E, 1998-2000




Presenter: M.Chierici (NIES, Japan)
P.I: Yukihiro Nojiri (NIES, Japan)
N.Tsurushima, K.Imai, S. Watanabe                                        Funded by CREST/
others
                            WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
  Planning of time series observation for
  Kyodo North pacific Ocean Time series
• JGOFS/North Pacific Task Team proposal for a new
  ocean time series station in the NW Subarctic Pacific
  (1996 Nov., Mutsu Symposium)
   – East/west comparison, subarctic/subtropical comparison
     with existing stations, P and HOT

• Trial of time series occupations by R/Vs of
  opportunity
   – Cooperative (Kyodo) program within Japanese institutions
   – Funded by JST/CREST for 1998-2000 intensive survey
     period
                       WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
KNOT observation in the campaign period (Jun. 1998 to 2000 Oct.)

         R/V         Date              R/V        Date                       R/V        Date
         1998 time series              1999 time series                      2000 time series
 Jan                  -                             -                       MIRAI        1/17
 Feb                  -                             -                       MIRAI         2/4
 Mar                  -                             -                                     -
 Apr                  -                             -                                     -
 May                  -               MIRAI      5/10, 23                   MIRAI      5/11, 22
 Jun    Hokusei     6/3, 26          Hokusei・ 6/3, 27,28                    MIRAI・     6/5,9,25
                                      Hakuho                                 Hokusei
 Jul    Hokusei         7/20          Hokusei      7/22                                            -
 Aug    Hokusei         8/13         Hokusei・    8/14,16                                           -
                                      Hakuho
 Sept                     -                         -                                            -
 Oct     Bosei         10/8, 14        Bosei    10/13, 18                     Bosei           10/13, 17
 Nov     MIRAI           11/9                       -                                            -
 Dec     MIRAI          12/11                       -                                            -

                  #8                              #10                                     #9
Dense coverage from May to October, Less coverage from November to April

                                  WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                     SK01-34: March 29, 1995 - March 17, 1999
            70N


            60N
                                                    WSG
            50N
 Latitude




            40N



            30N                                                       P
                            KNOT
            20N
              120E   130E   140E   150E   160E   170E     180 170W 160W 150W 140W 130W 120W 110W
                                                           Longitude
M/S Skaugran ship route of observation (Mar.1995-Mar.1999, 34
trips) and selected bands for seasonal functions.
1 million of pCO2 data. Data north of 34N were served for analysis using pCO2 seasonal
functions. Zeng et al., 2002
M/S Alligator Hope from Dec 1999 to March 2001(16 trips),
dense coverage in subarctic NP. Chierici et al. to be submitted
                                           WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                       KNOT in the NW Subarctic Pacific has the largest seasonal
                          amplitude in SST (HOT=3, P=7, KNOT=14 C).
                                          March
                             70N

                                                                                                             0
                                                                                                                                                                           March
                             60N                                                 4




                                                                      2 64
                                                                                                      0                 2
                                                                                          0

                             50N                                                                                                                  8


                                                                             0                                                        P
                                                              2


Produced by Dr. Jiye Zeng,(zeng@nies.go.jp)              0
                             40N
Global Environmental Forum, Japan                      4          6     4
                                                                        6
Mon Sep 06 11:17:02 1999                                8                 0
                                                                        112                                                                                12
                                                         10                 14
                                               6                       16                          KNOT
                                                                                                                                                                14
                                              14 218
                                                1 0




                                                                                                                                                      16
                                               116




                                                                                              18
                                                 8




                             30N                                                                                                 20
                                              20            22                                                       HOT                                              18
                                              24                                                                                            22
                             20N                                                                                                                                      22
                                   120E 130E 140E 150E 160E 170E September 160W 150W 140W 130W 120W 110W
                                                                  180 170W

                             70N
                                                                                                                 4
                                                                                                                                                                           September
                                                                                                             8




                             60N
                                                                             12
                                                                                     10




                                                                                                                       10
                                                                                                                                                 14
                             50N
                                                                                          10
                                                                         12




                                                                 20
                                                                 22
                                                                             16                18                                     P
                             40N                                        20
                                                                                                 22




                                                                                                                                                       16
                                                       24              24                          KNOT
                                              24
                                                                                                                                                                18
                                                                                                                                                 20
                             30N               26
                                                                                                                     HOT

                                                                                                                                                                 22
                                          28




                                                                                                                                       24


                                                                                                                                                                     26
                                                                                                                            26




                             20N
                                   120E 130E 140E 150E 160E 170E 180 170W 160W 150W 140W 130W 120W 110W

                                                                                                          WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
SeaWiFS image for North Pacific
 similar surface chlorophyll with station P




              WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                          Seasonal Amplitude of Nitrate (mmol/L)
           70N


           60N

                                                         12              15.0
                                                            .5                           10.0
           50N                                                                            7.5
Latitude




                                          15.0




                                                                                        7.5
                                                                       5.0                                  2.5
           40N                    12.5
                                  7.5
                                  5.0




                                                                 5.0
           30N
                                                                                P
           20N         KNOT
             120E   130E   140E    150E     160E     170E        180 170W 160W 150W 140W 130W 120W 110W
                                                                  Longitude

New production map of North Pacific estimated from seasonal
amplitude of nitrate in surface water observed by M/S Skaugran
Contour is the seasonal amplitude of nitrate change in mM.
(Seasonal surface nutrient change) x (MLD) approximately proportional to new production.
Summer MLD in Stn.P is almost twice as deep as MLD at KNOT;
                                      i.e. similar new production for P and KNOT
                                                 WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
          Comparison of primary productivity
          between station KNOT and station P
                                                2
Table Comparison of average daily (mgC/m /day) at station P and station KNOT
                               2
station                  mgC/m /day                     gC/m2/year                References
           Spring Summer Fall           Winter Annual productivity
P          415     466      366           283                 140             Wong et al. (1993)

KNOT 518           232      183            48                  90             This study
                                                                       Imai et al. (2002)

                                   WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                         Zeng et al. (2002) DpCO2 based on M/S Skaugran data (1995 to 1999)
                  undersaturated                                                                                                                                                            oversaturated
          -90                      -75                        -60

                                                                           January
                                                                                      -45                         -30                    -15                         0              15                       30                        45

                                                                                                                                                                                                                                             February
                                                                                                                                                                                                                                                                      60                             75                     90
                                                                                                                                                                                                                                                                                                                                                      KNOT area:
60N                                                                                                                                                                  60N

                                                                45        45 60                                                                                                                                                         60          75          45                                                                                    outgassing in winter




                                                                                                                                                                                                                             60
                                                                                                              15                                                                                                                                                                                  15
                                         30
50N                                                                                                                        -15         -15                           50N                                                                                                                                   -15       -15
                                                                                                                                                   -15 0




                                                                                                                                                                                                                                                                                                                                 -30
40N       0
         -30
         -45
                30


                                                                                                                           -4
                                                                                                                                                                     40N      30
                                                                                                                                                                               0
                                                                                                                                                                               -30
                                                                                                                                                                                       45



                                                                                                                                                                                                                                                                                 5
                                                                                                                                                                                                                                                                                                                                                      Largest oversaturation in February (45)




                                                                                                                                                                                                                                         -30
                      -60                                                                                                     5                                               -45                                                                                            -4                   -60
                                                                                                                                                                                       -60

30N                                                                                                                                                                30N
  140E      150E            160E             170E             180          170W            160W             150W            140W             130W             120W   140E       150E              160E               170E             180          170W               160W                 150W           140W             130W                120W
                                                                          March                                                                                                                                                                    April
60N                                                                                                                                                                  60N

-400        -350               -300                      -25060 -200
                                                                  4 5 30
                                                                                                  -150
                                                                                                                  15
                                                                                                                       -100                    -50                   0        50                  100                      150               200 5
                                                                                                                                                                                                                                               30
                                                                                                                                                                                                                                                           1
                                                                                                                                                                                                                                                                     -15   250
                                                                                                                                                                                                                                                                                               15
                                                                                                                                                                                                                                                                                                   300                350                      400
                                                                                                                                                                                                                                                                                                                                                      Early spring: sharp decrease in pCO2sw




                                                                                                                                                                                                                                                                                         0
50N                                                                                                                                                                  50N                                                                                                                                       -15
                                                                                                                                             -30                                                                                                                                                                                  -45




                                                                                                                                                                                            0
                                                                                                                                                                                 -                                                                                                                                                   -30
         15                                                                                                                                                                    -3015
40N       0                                                                                                                                                          40N
         -15
                                                                                                                                             -30




                                                                                                                                                                                  5
                                                        -30                                                   5                                                                -4




                                                                                                                                                                                                                                                                                                         -30
           -45                                                                                              -4                                                                   -30

30N
  140E      150E            160E             170E             180          170W
                                                                           May
                                                                                           160W             150W            140W             130W             120W
                                                                                                                                                                     30N
                                                                                                                                                                       140E     150E              160E               170E             180          170W
                                                                                                                                                                                                                                                   June
                                                                                                                                                                                                                                                                      160W                 150W           140W             130W                120W
                                                                                                                                                                                                                                                                                                                                                      Summer and fall
                                                                                                                                                                                                                                                                                                                                                      undersaturated by ~ 40 matm
60N                                                                                                                                                                  60N

                                                                     0           -4
                                                                               -30 5        -60                                                                                                                                              -30           -75
                                                                                                              0                                                                                                                                                             -6-0 5
                                                                                                                                                                                                                                                                               4
                                                                                                      -15




                                                                                                                                                                                                                                                                                     -15
                                                                                                                                                                                                                 0
50N                                                                                                                                                                  50N
                                                                                                                                  5




                                                                                                                                                                                                            0
                                                                                                                                  -1




                                                                                                                                                                                                     -30                                                                                                                   -30
                                                                                                                                                   -4                                                                                                                                                                                -60
                                    15                                                            -15
                         5




                                                                                                                                                     5                                                                                                                                                                               -4
                      -1




                                                                                                                                                                                                                                                                                                                                        5
                                                                                                                                                        -3                                                                                                                   -15
            -45




                                                                                                                                                                                -60




                                                                                                                                                          0
                                                                                                                                                                                                                                                                                                                                     -1
          -60




                                                                                                                                                                                                                                                                                                                                       5
                                                                                                                                                                                5




40N                                                                                                                                                                  40N
                                                                                                                                                                              -7




                                                                                                                                                                              -45
         -30 -15                                                                                                                                                              -15 0                                                                                                  0
                                                                0




                                                                                                                       0




                                                                                                                                                                                                                                                                                                          15
                                                                                                                                                                                                                                                                                                           5
30N                                                                                                                                                                  30N
  140E      150E            160E             170E             180          170W            160W             150W            140W             130W             120W     140E     150E              160E               170E             180          170W               160W                 150W           140W             130W                120W
                                                                           July                                                                                                                                                                August
60N                                                                                                                                                                  60N

                                                                     -45                                                                                                                                                                           -45                     -60
                                                                                             -7-5 0
                                                                                                6
                                                                                                   -30




                                                                                                                                                                                                                            -3
                                             -1




                                                                                                                                                                                                                              0
                                              15




50N                                                                                                                                                                  50N                                                                                                                       -15
                                                                                                                                                                                                         -15 0




                              -45                                                                                                                                                                                                                                                                                          -15
                                                                                                                                                                                                           -3




                                                                                                                                                    -4
                                                                                                                                                   -3




                                                                                                                                                      5
                                                                                                                                                   0




                                                                                                                                                                                            -45




                                                                                                                                                                                                                                                                                                                                     -30 -15
                  5




                                                                                                                                                                                                                                                                                                                                         -
               -4




                                                                                                                                                                                -45
                                                                                                                                                    -1
           0
         -6




                                                                                                                                                       5




40N                                                                                                                                                                  40N      -15
         -30                                                                                                                                                                                                                                                                                                                           15
                                                                                                                                                                                                                                                                                  0
                                                                                                                                                                                                                                                               -15




                                                                                                                                                         15
         -15                                                                                                                                                                                                               -15
                                                                                                                                                                                                                                                                                             30
                                                                                                  0


                                                                                                              30




                                                                                                                                                                                                                                                   0




                                                                                                                                                                                                                                                                                                               45
                                                               0




30N                                                                                                                                                                  30N
  140E      150E            160E             170E             180          170W            160W             150W            140W             130W             120W     140E     150E              160E               170E             180          170W               160W                 150W           140W             130W                120W
                                                                    September                                                                                                                                                                October
60N                                                                                                                                                                  60N

                                                                    -15                                                                                                                                                           0                    0
                                              -15                                                   -30                       5                                                                                                                                      -15
                                                                                                                           -1                                                                                                                                                                            -15
50N                                                                                                                                                                  50N                          -3                                                           -30
                                                                                                                                                                                                     0                                                                                                                           0
                                                                           0
                      -45




                                                                                                                                                                                                                       0
                                                                                                                                                    -
                                                                                                                                                    -15




                                                    0
                                                                                              -15




            -45
                                                                                                                                                                                                                                                                                     -15




40N       -30                                                                                                                                             0          40N                                                                                                                                                                0
         -15                                                                                                                            30                                    -45
                                                                     -15               -30
                                                                                                                                                                                                                                                           -30
                                                                                                            15




                                                                                                                                                                                                                                                                                                         15




                                     -30                                                                                                                                                                                                                                                                        30

30N                                                                                                                                                                  30N
  140E      150E            160E             170E             180          170W            160W             150W            140W             130W             120W     140E     150E              160E               170E             180          170W               160W                 150W           140W             130W                120W
                                                                    November                                                                                                                                                                 December
60N                                                                                                                                                                  60N

                                                                                15                                                                                                                                                                         30
                                                               15                                                                                                                                                                       30                                                           0
                                         0




50N                          -15                                                                                                                                     50N                                                                                                                                              -15
                                                                                                                                                                                                                 15




                                                                                     -30                                                -15         15
                                                                                                                                                      0                                                                                                                                                                                 0
                                                                                                                                                                                            0




                                                                                                                                                                                       0
                -45                                                                                                                                                                 -15
         -60                                                                                                                                                                  -30
40N      -75                                                                                                                                                         40N      -45
                                                                                      -45                                                                                     -60
                                                                                                        -30




                                                                                                                                                                                                                                                                                         -45
                                                                                                                                                                                                                 -60
                                                                                                                              0




         -45

30N                                                                                                                                                                  30N
  140E      150E            160E             170E             180          170W            160W             150W            140W             130W             120W     140E     150E              160E               170E             180          170W               160W                 150W           140W             130W                120W



                                                                                                                                                                                                                                        WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
Summer MLD
  < 20 m                      Potential Temp. (°C)                                                       Salinity
                  0   2   4       6    8    10   12    14   16                     32.0     32.5       33.0     33.5   34.0   34.5
             0                                                                     0




            100                                                                   100


                                   Winter mixing depth
            200                                                                   200
                                                                                        halocline of 1 ppt
depth (m)




                                                                      depth (m)
                                       1999
                                                                                           1999
            300                              5 June                               300
                                                                                                   5 June
                                            27 June                                                27 June
                                            22 July                                                22 July
                                            14 Aug.                                                14 Aug.
            400                                                                   400




            500                                                                   500
       · ¼ 
          ª z                                                                        
                                                                                    ª ¼ ª z
       27 June, 14 Aug.: 
 Halocline at 100-200 Im. Thermocline
                         T ^  È ¦ Ñn
                                  100-120                                                              
                                                                                    27 June, 14 Aug.: T ^ I È ¦ Ñ n 
                                                                                   m, depending on winter climate.
                          Ñ n
       5 June, 22 July: M 
                                Ì e ¿ L è                                                               
                                                                                    5 June, 22 July: M Ñ n Ì e ¿ L è
 Shallow summer thermocline (<20 m).

                                                      WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                               100mmol/kg




Surface DIC and Alkalinity (S=35 normalized)
          Outliers are subtropical water intrusion.
                    WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                     20

                               Interannual variability of SST                              SST time series
                     15
                                                                                          at Station KNOT
Temperature (°C)




                     10                                                                    from 1998-2000
                     5
                                                                                     No clear interannual variability in SST


                     0
                               1998            1999                 2000

                     20
                                                                                      Seasonal variability for each year

                     15        1998
  Temperature (°C)




                               1999
                               2000                                                      Seasonal SST amplitude ~ 14 C
                     10
                                                                                               but no winter data
                                                                                  Perhaps summer 1999 warmer than 1998
                      5


                                                            WG I: KNOT...Understanding NP C-
                      0                                    cycle changes: workshop Seattle 2-4th
                          Jan Feb Mar Apr May Jun                         Dec
                                                    Jul Aug Sep Oct Nov June 2004
                      25


                      20
Nitrate (µmol / kg)




                                                                               DNO3 >17
                      15


                      10         1998
                                 1999
                                 2000
                      5


                      0
                           Jan Feb Mar Apr May Jun             Jul Aug Sep Oct Nov Dec

                              Surface nitrate time series
                                Outliers are subtropical water intrusion
                                           WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                                                Tsurushima et al., 2002

         fCO2sw ranged from 390 in May to 290 matm in Oct




                      Two minima




Observed seasonal change in surface fCO2 at KNOT

                  WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
                                                           Chierici et al., to be submitted
Using data obtained from VOS survey 2000 to take a look at KNOT area
 Monthly values for all parameters in 5 Lon grid: Sigmoidal function expressed by
   harmonic fit to observed data (Zeng et al. 2002)

 Example for fCO2sw, where t = time (month), c0 to c4 are seasonal terms

 fCO2sw (t) = c0 + c1 sin (2 t) + c2 cos (2 t) + c3 sin (4 t) + c4 cos (4 t)

430       matm
                             fCO2 sw
                                                     K 5 °Lon area
                                                                           Lack of data in March and
410                                                                         April at KNOT makes it
                                                     KNOT98
390                                                  KNOT99/2000           difficult to address whether
                                                                            KNOT acts as an oceanic
370
                                                                                 sink or source for
350         100                                                                 atmospheric CO2.
330
           matm
                                                                                and what does
310                                                                        the Grid data indicate….
290
      1     2    3   4   5     6   7      8     9     10     11      12
                               Month


                                   WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
            Sea-air CO2 fluxes at KNOT and from a 5Lon Grid
                                                                                              M/S Alligator Hope cruises in 2000

Wind speed from NCEP/NCAR Reanalysis
monthly averages of 6-hr winds
Flux parameterization: Wanninkhof, 1992


At KNOT: Oceanic sink of atm.CO2
in summer and fall 7 to 10 mmol C m-2 d-1,
Max. flux in Oct-99 of 14 mmol C m-2 d-1,                                                             WSG
                                                                                                  


          mmol C m -2 yr-1
 15                                  Sea-air CO2 flux
                                                                                                            5 Lon grid and WSG
                                                                                        KNOT                from study Chierici et al., to be submitted
                                                                       K-1998
 10
                                                                       K-1999-2000
                                                                       WSG 2000
  5
                                                                       K 5 °Lon area
                                                                                           However, using underway fCO2 data (VOS
  0                                                                                    program) we estimated the sea-air flux in a larger
                                                                                        area (5 Lon) and in the Western Subarctic Gyre
 -5
                                                                                       (WSG), where KNOT is located in the SW corner
-10                                                                                    (Chierici et al., to be submitted).

-15
          Summer: KNOT sink                                                            Underway data indicates small oceanic
-20
      1     2      3         4   5      6      7        8   9     10      11     12
                                                                                       sink of – 0.14 mol m-2 yr-1
                                         month
                                                                                                 Oct. flux agree
                                                                WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
Modeled seasonal change in surface dissolved inorganic carbon
in time series stations. DIC change of northern hemisphere station has a
same phase but different amplitude.
                          WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
 Results of time series KNOT (1998-2000)

• 27 visits but uneven seasonal coverage
  – Only MIRAI visit in true winter (2000)
  – Absence of occupation in March and April, minimum
    SST period of vertical mixing
  – Confirming maximum seasonal amplitudes in SST,
    nutrients and DIC in the time series stations
  – Shallow mixed layer depth in the productive period
  – Relatively small annual average PP (primary
    production), large seasonal amplitude in PP, and
    extremely low PP in winter
                    WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
 What learned from time series KNOT
• Difficulty in the open ocean time series
   – 2-3 days of sailing to the time series location, minimum
     of two week cruise
   – Ship time sharing with regular research cruise,
     unnecessarily long cruise for time series members
   – Analytical quality control within different institutions,
     fortunately successful by standards and inter-calibration
• HOT and BATS time series
   – Open ocean time series with neighboring island base,
     monthly visit by a fixed R/V of one week cruise
• Restart of KNOT time series occupation?
• Data set publication through JODC
                      WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004
               KNOT data web site
               (in preparation)




               Special thanks:
               KNOT core members
               scientists of participating
               institutes and universities
               participating research vessels

               KNOT program is funded by
               JST/CREST.
WG I: KNOT...Understanding NP C-cycle changes: workshop Seattle 2-4th June 2004