Draft Cruise Report World Ocean Circulation Experiment Indian Ocean Hydrographic Program Section I2 R/V KNORR Voyage 145-14 2 December 1995 - 22 January 1996 A. Cruise Narrative A.1. Highlights WOCE Hydrographic Program Section I2 (EXPCODE 316N145/14) was carried out aboard the R/V KNORR on voyage 145-14. This voyage began in Singapore on 2 December 1995 and ended in Mombasa, Kenya on 22 January 1996 with an intermediate port call in Diego Garcia from 28 to 30 December 1995. The chief scientist from Singapore to Diego Garcia was Gregory Johnson: NOAA/Pacific Marine Enviromental Laboratory, Ocean Climate Research Division, 7600 Sand Point Way NE Bldg. 3, Seattle WA 98115, USA, gjohnson@pmel.noaa.gov. The chief scientist from Diego Garcia to Mombasa, Kenya was Bruce Warren: Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, bwarren@whoi.edu. A.2. Cruise Summary The work done during this cruise comprised WOCE Hydrographic Program Section I2, a transindian ocean section along nominal latitude 8oS, and three diversions to nearby gaps in ridges to explore possible avenues for flow of deep and bottom water between various deep basins. During the cruise a total of 168 CTD/O2 stations were occupied within 10 m of the bottom with a 36 position 10-l bottle frame equipped with a lowered ADCP. Discounting one test station, 139 of these stations were occupied along the I2 section. The nominal station spacing along the I2 section is 40 nm in the interior, reduced near boundaries, mid-ocean ridges, and other places where narrow currents might exist. The average station spacing along the section is 32 nm. The positions of the CTD stations are plotted in Fig. 1, and the distribution of points along the main section at which water samples were drawn is plotted in Fig. 2. Special attention was given to the bottom topography in laying out the station positions because of the opportunity offered for the exploration of the three major deep flows in the South Indian Ocean. The deep western boundary current of the eastern Indian Ocean, flowing northward along the Ninety east Ridge, had never been observed north of 18oS. The central deep boundary current had been inferred to divide near 15oS, with ill- defined branches flowing northward along the Chagos-Laccadive Ridge, Central Indian Ridge, and Mascarene Plateau. In the west the major deep and mid- depth flows between the Mascarene and Somali Basins could be documented on a complete section from the Mascarene Plateau to Madagascar. Three diversions were made from the main section to investigate flow of bottom water through deep gaps in mid-ocean ridges. The first diversion, 7 stations from 6o 50'S to 5oS around a mean longitude of 88o 28'E, mapped a westward flow of bottom water from the West Australian Basin to the Central Indian Basin across a deep gap in the Ninety east Ridge at 5oS. The second diversion consisted of 11 stations between 11oS - 10oS and 88oE - 88o 25'E to investigate a similar flow across a gap in the ridge at 10oS. The third diversion consisted of 10 stations between 4o 00'S - 2o 30'S and 71o 45'E - 73o 20'E, placed within and on the western flank of a deep gap in the Chagos- Laccadive Ridge. This diversion explored, for the first time, suspected flow of bottom water through this gap between the Central Indian Basin and the Arabian Basin. The ship left Singapore at 0900L on 2 December 1995 without the Indonesian observers, who had elected not to participate since clearance to work within the Indonesian Exclusive Economic Zone was not obtained. After a roughly 3 day steam, stations 1077 and 1078 were occupied at the location of station 1075, occupied ten days earlier during I10, at 9o S, 105o 38'E; these served as test stations for equipment and personnel. Stations 1079 though 1084 went from 105o 10'E to 102oE along 9o 7.5'S. By station 1090 the line reached 8oS at 98oE, after skirting the offshore edge of the Indonesian Exclusive Economic Zone (EEZ). The ship crossed the Ninetyeast Ridge at station 1105, and the Chagos-Laccadive Ridge at 1154. Stations 1106-1112 and 1116-1126 comprised the first two diversions from the main section along 8oS. The cruise broke off after station 1156 for a 48 hour port call in Diego Garcia, where Gregory Johnson departed to join another cruise and the two Kenyan observers joined the ship. After departing Diego Garcia at 0900L 30 Dec 1995 the ship steamed north for the third diversion, at the Chagos- Laccadive gap, stations 1157- 1166. Returning to the 8oS line, it passed the crest of the Central Indian Ridge at station 1172, and that of the Mascarene Plateau at station 1185. At station 1194 at 54oE, the ship's course turned southwestward to cross the Amirante Passage (stations 1199-1201 in the Amirante Trench proper) and reached the northern tip of Madagascar at station 1215. After rounding the tip, the ship resumed stations heading northwestward toward Africa, taking a dog-leg track with turns at stations 1227 and 1232 to avoid the Tanzanian EEZ, and arriving in Mombasa on 22 January 1996 after completing station 1244. Twenty-seven Autonomous Lagrangian Circulation Explorer (ALACE) floats and twenty surface drifters were deployed during the course of the cruise. Serial numbers, launch dates, launch times, positions, and CTD station numbers corresponding to launch sites are listed in Tables 1 and 2, respectively. An underway program of meteorological, sea surface, and hull- mounted ADCP measurements was carried out along the entire cruise track outside the Indonesian EEZ. For a non-WOCE, adjunct project, 25-ml samples for barium analysis ashore were drawn from every Niskin bottle on alternate stations, and stored for shipment to the U.S. Table 1. WOCE-I2 ALACE Float Deployment Log. Date and time shown in GMT. After -SELF TEST- ---------------DEPLOYMENT----------- CTD S/N Date Time Date Time ----Lat---- ----Lon----- Stn# 1. 560 951206 1158 951206 1407 9o 07.70'S 103o 20.10'E 1082 2. 561 951208 1107 951208 1124 8o 22.42'S 98o 20.01'E 1088 3. 573 951212 1008 951212 1326 7o 59.91'S 91o 20.20'E 1100 4. 574 951214 2004 951214 2155 5o 00.22'S 88o 28.25'E 1109 5. 568 951216 1206 951216 1510 8o 00.14'S 87o 59.85'E 1115 6. 567 951218 0001 951218 0154 11o 00.06'S 88o 01.93'E 1120 7. 563 951221 1600 951221 1900 8o 00.06'S 83o 19.57'E 1133 8. 549 951223 0419 951223 0618 8o 00.31'S 79o 59.84'E 1138 9. 562 951225 0007 951225 0207 7o 59.92'S 75o 59.90'E 1144 10. 495 951226 1423 951226 1618 7o 59.88'S 72o 49.56'E 1150 11. 535 951227 1335 951227 1532 7o 59.71'S 70o 39.20'E 1156 12. 538 960104 1935 960104 2048 8o 00.06'S 67o 19.93'E 1172 13. 570 960106 1517 960106 1742 8o 00.28'S 62o 39.77'E 1179 14. 569 960107 0450 960107 0628 8o 00.45'S 61o 27.08'E 1181 15. 550 960107 2327 960108 0035 7o 59.96'S 59o 19.99'E 1185 16. 557 960109 1501 960109 1752 8o 00.10'S 55o 19.57'E 1192 17. 555 960111 0705 960111 1008 8o 56.92'S 53o 02.88'E 1200 18. 558 960112 0914 960112 1227 9o 32.84'S 51o 54.29'E 1205 19. 556 960113 1125 960113 1436 11o 12.53'S 50o 47.23'E 1209 20. 553 960114 0707 960114 0946 12o 12.24'S 49o 47.87'E 1213 21. 571 960114 2209 960115 0158 11o 54.06'S 48o 44.03'E 1218 22. 554 960116 0149 960116 0412 10o 16.80'S 47o 30.30'E 1223 23. 572 960117 0010 960117 0137 8o 44.88'S 46o 20.50'E 1226 24. 552 960117 2028 960117 2103 7o 00.47'S 45o 57.29'E 1229 25. 564 960119 0046 960119 0355 5o 02.51'S 45o 16.75'E 1233 26. 565 960120 0605 960120 0852 4o 33.47'S 42o 41.33'E 1237 27. 551 960121 0036 960121 0206 4o 15.63'S 40o 58.22'E 1240 Table 2. WOCE I2 Surface Drifter Deployment Log. Date and time shown in GMT. After ---------------DEPLOYMENT----------- CTD S/N Date Time ----Lat---- ----Lon----- Stn# 1. 21904 120595 1508 9o 07.98'S 105o 09.99'E 1079 2. 21903 120895 0346 8o 33.77'S 99o 59.65'E 1087 3. 21933 121095 1709 8o 00.41'S 95o 20.26'E 1094 4. 21932 121395 0254 7o 59.96'S 89o 59.84'E 1102 5. 21870 121495 0533 6o 00.10'S 88o 28.56'E 1106 6. 21871 121495 2200 5o 00.36'S 88o 28.49'E 1109 7. 21905 121695 1511 8o 00.20'S 87o 59.84'E 1115 8. 21901 121795 0520 10o 02.88'S 87o 59.98'E 1116 9. 21912 121895 1557 10o 59.99'S 88o 01.93'E 1120 10. 21913 122095 2148 7o 59.97'S 85o 19.97'E 1130 11. 21921 122395 0620 8o 00.33'S 79o 59.81'E 1138 12. 21920 122595 0918 7o 59.97'S 75o 19.88'E 1145 13. 21926 010196 0029 2o 30.30'S 72o 32.24'E 1160 14. 21928 010396 1956 7o 59.84'S 69o 59.86'E 1168 15. 21929 010596 1653 7o 59.95'S 65o 19.75'E 1175 16. 21927 010796 1724 7o 59.90'S 60o 09.62'E 1183 17. 21952 010996 1753 8o 00.10'S 55o 19.33'E 1192 18. 21951 011596 2134 10o 46.69'S 47o 52.15'E 1222 19. 21923 011796 2205 7o 00.40'S 45o 57.26'E 1229 20. 21922 012096 1515 4o 27.84'S 42o 06.66'E 1238 A.3. Principal Investigators 1. Gregory Johnson, Salinity Oxygen CTD/O2, NOAA/Pacific Marine Environmental Laboratory, Ocean Climate Research Division, 7600 Sand Point Way NE Bldg. 3, Seattle WA 98115-0070, USA, gjohnson@pmel.noaa.gov 2. Bruce Warren, Salinity Oxygen CTD/O2, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, bwarren@whoi.edu 3. John Toole, Salinity Oxygen CTD/O2, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, jtoole@whoi.edu 4. Louis Gordon, Nutrients, Oregon State University, College of Ocean and Atmospheric Sciences, 104 Ocean Administration Building, Corvallis OR 97331-5503, USA, lgordon@oce.orst.edu 5. John Bullister, CFCs (F11, F12) & Air Chemistry, NOAA/Pacific Marine Environmental Laboratory, Ocean Climate Research Division, 7600 Sand Point Way NE Bldg. 3, Seattle WA 98115-0070, USA, bullister@pmel.noaa.gov 6. William Jenkins, Shallow Helium/tritium, Woods Hole Oceanographic Institution, Chemistry Department, Woods Hole MA 02543, USA, wjenkins@whoi.edu 7. Peter Schlosser, Deep Helium, Lamont Doherty Earth Observatory, Columbia University, Pallisades NY 10964, peters@ldeo.columbia.edu 8. Robert Key, AMS C14 & Radium, Princeton University, Geology Department, Guyot Hall, Princeton NJ 08544, USA, key@wiggler.princeton.edu 9. Kelly Falkner, Barium, Oregon State University, College of Ocean and Atmospheric Sciences, 104 Ocean Administration Building, Corvallis OR 97331-5503, USA, kfalkner@oce.orst.edu 10. Chris Winn, Total Carbon & Alkalinity, Scripps Institution of Oceanography, Marine Physical Laboratory 0902, University of California at San Diego, 9500 Gilman Drive, La Jolla CA 92037, USA, cwinn@chiton.ucsd.edu 11. Douglass Wallace, Total Carbon & Alkalinity, Brookhaven National Laboratory, Building 318, Upton NY 11973, USA, wallace@bnl.gov 12. Peter Hacker, ADCP & LADCP, University of Hawaii, Joint Institute for Marine and Atmospheric Research, 1000 Pope Road, Honolulu HI 96882, USA, hacker@soest.hawaii.edu 13. Eric Firing, ADCP & LADCP, University of Hawaii, Joint Institute for Marine and Atmospheric Research, 1000 Pope Road, Honolulu HI 96882, USA, efiring@soest.hawaii.edu 14. Barrie Walden, Meteorology, Woods Hole Oceanographic Institution, Woods Hole MA 02543, USA, bwalden@whoi.edu 15. Russ Davis, ALACE Floats, Scripps Institution of Oceanography, University of California at San Diego 0230, 9500 Gilman Drive, La Jolla CA 92093-0230, USA, davis@nemo.ucsd.edu 16. Mark Bushnell, Surface Drifters, NOAA/Atlantic Oceanographic Marine Laboratory, 4301 Rickenbacker Causeway, Miami FL 33149, USA, bushnell@aoml.noaa.gov A.4. List of Cruise Participants 1. Gregory Johnson*, chief scientist, NOAA/Pacific Marine Environmental Laboratory, Ocean Climate Research Division, 7600 Sand Point Way NE Bldg. 3, Seattle WA 98115- 0070, USA, gjohnson@pmel.noaa.gov 2. Bruce Warrren**, co-chief scientist, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, bwarren@whoi.edu 3. Sara Zimmermann, CTD data processor, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, szimmermann@whoi.edu 4. George Knapp, oxygen analyst, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, gknapp@whoi.edu 5. Toshiko Turner (WHOI) salinity analyst, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, tturner@whoi.edu 6. H. Marshall Swartz, CTD electronics technician & CTD watch leader, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, mswartz@whoi.edu 7. Laura Goepfert, CTD watch leader, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, lgoepfert@whoi.edu 8. Paul Bennett, CTD watch stander, Woods Hole Oceanographic Institution, 110 High Park Place, Pittsburgh PA 15266, USA 9. Steven Jayne, CTD watch stander, Woods Hole Oceanographic Institution, Department of Physical Oceanography, Woods Hole MA 02543, USA, sjayne@whoi.edu 10. Arthur Voorhis, CTD watch stander, Woods Hole Oceanographic Institution, 54 Whitman Road, Woods Hole MA 02543, USA 11. Mela Swapp, CTD watch stander, University of Washington, P.O. Box 8231, Kirkland WA 98034, USA, swapp@pmel.noaa.gov 12. Deborah LeBel, CTD watch stander, University of Washington, School of Oceanography, Box 357940, Seattle WA 98195-7940, lebel@ocean.washington.edu 13. Stanley Moore, Nutrient analyst, Oregon State University, College of Ocean and Atmospheric Sciences, 104 Ocean Administration Building, Corvallis OR 97331-5503, USA, moores@ucs.orst.edu 14. Consuelo Carbonell-Moore, Nutrient analyst, Oregon State University, College of Ocean and Atmospheric Sciences, 104 Ocean Administration Building, Corvallis OR 97331-5503, USA, carbonec@oce.orst.edu 15. Elodie Kestenare, ADCP & LADCP watch leader, University of Hawaii, Joint Institute for Marine and Atmospheric Research, 1000 Pope Road, Honolulu HI 96882, USA, elodie@soest.hawaii.edu 16. Mark Majodina, ADCP & LADCP watch stander, University of Cape Town, Oceanography Department, Rondebosch 7700, SOUTH AFRICA, majodina@physci.uct.ac.za, 17. Frederick Menzia, CFC analyst, NOAA/Pacific Marine Environmental Laboratory, Ocean Climate Research Division, 7600 Sand Point Way NE Bldg. 3, Seattle WA 98115-0070, USA, menzia@pmel.noaa.gov 18. Bing-Sun Lee, CFC analyst, University of Washington, School of Oceanography, Box 357940, Seattle WA 98195-7940, blee@pmel.noaa.gov 19. Art Dorety, C-14 and Radium analyst, Princeton University, Geology Department, Guyot Hall, Princeton NJ 08544, USA, key@wiggler.princeton.edu 20. Dan Smith, Deep Helium-3 analyst, Lamont Doherty Earth Observatory, Columbia University, Pallisades NY 10964, dansmith@lamont.ldgo.columbia.edu 21. Scot Birdwhistell, Tritium/Helium-3 analyst, Woods Hole Oceanographic Institution, Chemistry Department, Woods Hole MA 02543, USA, sbirdwhistell@whoi.edu 22. Rolf Schottle, TCO2/Alkalinity analyst, Scripps Institution of Oceanography, Marine Physical Laboratory 0902, University of California at San Diego, 9500 Gilman Drive, La Jolla CA 92037, USA, rolfs@chiton.ucsd.edu 23. Jennifer Phillips, TCO2/Alkalinity analyst, University of Hawaii at Hilo, Department of Marine Science. 200 West Kawili St, Hilo HI 96720, jphillip@hawaii.edu 24. Angela Adams, TCO2/Alkalinity analyst, University of Hawaii, Department of Oceanography, 1000 Pope Road, Honolulu HI 96822, aadams@soest.hawaii.edu 25. Cathy Cipolla, TCO2/Alkalinity analyst, University of Rhode Island, Graduate School of Oceanography, Equipment Development Laboratory, South Ferry Road - Box 60, Narragnasett RI 02882-1197, USA, seabiz@gsosun1.gso.uri.edu 26. Stanley Rosenblad, Resident Technician, Woods Hole Oceanographic Institution, Woods Hole MA 02543, USA, srosenblad@whoi.edu 27. Michael Mutua Nguli***, Kenyan scientist, Kenya Marine and Fisheries Research Institute, P.O. box 81651, Mobassa, KENYA, modido@main.bib.uia.ac.be 28. Mika Oduor Odido***, Kenyan scientist, Kenya Marine and Fisheries Research Institute, P.O. box 81651, Mobassa, KENYA, modido@main.bib.uia.ac.be *Departed Ship in Diego Garcia **Chief Scientist from Diego Garcia to Mombasa ***Joined ship in Diego Garcia A.5. Special Notes Extraordinary time and effort were expended by the chief scientistand Indonesianscientists from the Bogor Agricultural University in an attempt to gainclearance to occupyhydrographic stations within the Indonesian EEZ as part of WOCE Section I2.Formalclearance was never granted. Late on 30 November 1995 one of theIndonesian scientistsinvolved called the Chief Scientist saying that he had obtained clearance.He requested athree day delay in the start of I2 to accommodate the schedules of theIndonesian militaryobservers. The stations to be allowed started 19 nm from the Indonesiancoast at about2000 m depth. After a brief consideration weighing the experience gainedin Indonesianclearance procedure from the preceding cruise, WOCE Section I10, a decisionwas made tostart the cruise on time and abandon hope of working within the IndonesianEEZ. Thislack of clearance was most unfortunate as measurent of the South JavaCurrent, most likelyflowing southeastward along Indonesia, had to be omitted from the program. B. Underway Measurements B.1. Navigation and Bathymetry To obtain bathymetric data, uncorrected sonic depths and times werelogged manuallyfrom the 12 khz PDR every 5 minutes by the CTD watch. These depths werethen mergedby time with the navigation data. B.2. Meteorological Observations The IMET system was calibrated prior to the departure of the Knorrand extra sensorswere aboard. The data were automatically recorded once per minute on the ship'scomputer. Variables measured included computer time, ship's heading (Gyrosyncro),ship's speed (EDO Speedlog), sea surface conductivity (mmho/cm), sea surfacetemperature (oC), port GPS 200 time & position, stbd GPS 200 time &position, GPScourse over ground, GPS speed over ground, GPS time & position, airtemperature (oC),barometric pressure (millibars), relative humidity (percent), precipitation(millimeters),short wave radiation (watts/sq m), compass reading (degrees), winddirection (shiprelative), and wind speed (m/s, ship relative). The quality of the windrecords may havebeen degraded sometimes when red-footed boobies (Sula sula) sat on the sensors. B.3. Acoustic Doppler Current Profilers Ocean velocity observations were taken using two acoustic Dopplercurrent profiler(ADCP) systems and accurate navigation data. The two systems are thehull-mountedADCP and a lowered ADCP mounted on the rosette with the CTD. The purposeof theobservations was to document the upper ocean horizontal velocity structurealong the cruisetrack, and to measure vertical profiles of the horizontal velocitycomponents at theindividual hydrographic stations. The observations provide absolutevelocity estimatesincluding the ageostrophic component of the flow. B.3.1. Hull-mounted ADCP The hull-mounted ADCP is part of the ship's equipment aboard the KNORR. The ADCP is a 150 kHz unit manufactured by RD Instruments. The instrument pings about once per second, and for most of the cruise the data were stored as 5-minute averages or ensembles. The user-exit program, ue4, receives and stores the ADCP data along with both the P-code navigation data from the ship's Magnavox receiver and the Ashtech gps receiver positions. The P- code data are used as navigation for the ADCP processing. The ship gyro provides heading information for vector averaging the ADCP data over the 5- minute ensembles. The user-exit program calculates and stores the heading offset based on the difference between the heading determination from the Ashtech receiver and from the ship gyro. The ADCP transducer is mounted at a depth of about 5 meters below the sea surface. The setup parameters were a blanking interval of 4 meters, a vertical pulse length of 16 meters, and a vertical bin size of 8 meters. We used a 5 minute sampling interval for the entire cruise. Bottom tracking was activated during the shallow water transits near Diego Garcia Atoll, and along the coasts of Madagascar and Mombasa. For the processing of the ADCP data aboard ship, we used a rotation amplitude of 1.0085, a rotation angle of -0.06 degrees (added to the gyro minus gps heading), and a time filter width of 0.0104 days (15 minutes). Final editing and calibration of the ADCP data has not yet been done. A couple of days before arriving at Diego Garcia, the performance of beam 4 became poorer than usual. During the second leg (Diego Garcia - Mombasa), the beam 4 failed and the three other beams were going slowly worse and worse. Several tests have been done: the results confirm that the main electronics works well but a problem occurs inside the transducers. We suspect that beam 4 (and maybe the three others) has flooded. A complete set of preliminary plots was generated during the cruise. The plots consist of: vector plots with velocity averaged over several depth intervals, and over a tenth or a twentieth of degrees in spatial grid; and contour plots of u (positive east) and v (positive north) typically averaged over 0.1 degree of longitude or latitude, depending on the track. The velocity was measured from a depth of 21 m to a depth of about 300 to 400 m, typically during the first leg and about 200 to 300 m during the second leg since a beam failed. B.3.2. Lowered ADCP The second ADCP system is the lowered ADCP (LADCP), which was mounted to the rosette system with the CTD. The LADCP yields vertical profiles of horizontal velocity components from near the ocean surface to near the bottom. Two LADCP were available: Teresa Chereskin's (Scripps Institution of Oceanography - SIO) and Eric Firing & Peter Hacker's (University of Hawaii - UH). Both units are a broadband, self-contained 150 kHz system manufactured by RD Instruments. The SIO instrument, used with an asynchronous signal (with alternating sampling intervals of about 1.2 and 1.8 seconds), allows one to decrease the number of samples contaminated by bottom interference. We used single ping ensembles. Vertical shear of horizontal velocity was obtained from each ping. These shear estimates were vertically binned and averaged for each cast. By combining the measured velocity of the ocean with respect to the instrument, the measured vertical shear, and accurate shipboard navigation at the start and end of the station, absolute velocity profiles are obtained (Fisher and Visbeck, 1993). Depth is obtained by integrating the vertical velocity component; a better estimate of the depth coordinate will be available after final processing of the data together with the CTD profile data. The shipboard processing results in vertical profiles of u and v velocity components, from a depth of 60 m to near the ocean bottom in 16-m intervals. These data have been computer contoured to produce preliminary plots for analysis and diagnosis (see enclosed figures). The SIO (newest) LADCP was used between CTD stations 1077 and 1094. The very poor performance of the instrument below 3000 m and then below 2000 m during these first 18 stations is due to a low transmit current inside the instrument (the HP module failed). The UH LADCP was used from station 1095 until the end of the cruise. Five stations (1015, 1118 - 1121) were missed owing to the use of an improper configuration file. One command required for proper LADCP operation with the new resistor (changed July 95) was not included correctly in the initial file. Also, the LADCP was not deployed during station 1215, because of shallow water (around 300 m). The deep casts often have noise problems below 3000 m or so owing to poor instrument range and interference from the return of the previous ping. B.3.3. Navigation The ship used a Trimble precision code (P-code) receiver for navigation, with data coming in once per second. These one-second data were stored for the entire cruise. The Ashtech receiver uses a four antennae array to measure position and attitude. The heading estimate was used with the gyro to provide a heading correction for the ADCP ensembles. The Ashtech data were stored by the ADCP user-exit program along with the ADCP data. B.4. Thermosalinograph Surface temperature and salinity from an FSI thermosalinograph were recorded on the ship's computer. The thermosalinograph was not calibrated prior to the departure of the Knorr from Woods Hole and will require station calibrations with the CTD/rosette system to obtain correct salinity data. B.5. Atmospheric Chemistry The CFC group ran 3/8" O.D. Dekaron air sampling lines (reinforced plastic tubing) from the CFC van to the bow and stern and their personell periodically analysed air for: CFC-11, CFC-12, CFC-113, carbon tetrachloride, and methyl chloroform. B.6. pCO2 Equilibrated seawater and surface air were monitored underway for pCO2 by the TCO2 and Total Alkalinity personell. Two separate systems were continuously monitoring pCO2. One system uses a shower type equilibrator and gas chromatographic detection. The other system uses a rotating disk equilibrator and infra-red detection. Sample analyses were typically completed within 12 hours of sample collection for discrete samples (TCO2 and Total Alkalinity). C. Hydrographic Measurements C.1. Water Sampling (Rosette) Equipment 2 SIO/ODF 36 position/10-liter frame with LADCP mounts. 1 WHOI/Bullister 25 position/4-liter frame. 1 WHOI 24 position/1.2 liter frame. 80 SIO/ODF 10-liter bottles with spares. 32 WHOI/Bullister 4-liter bottles with spares. 28 Bullister 4-liter bottles with spares. 36 WHOI/GO 1.2 liter bottles with spares. 3 GO 36-position pylons model 1016-36. 2 GO 24-position pylons model 1015-24. 2 GO 36-position surface control interfaces. 2 GO 24-position pylon deck units. 1 GO GO-FIRE external tonefire system for 36-position pylons. C.2. CTD Data acquisition and processing C.2.1. CTD Equipment 3 WHOI-modified EG&G Mk-IIIb CTD/O2 system with WHOI titanium pressure transducer and pressure temperature channel. 2 WHOI/FSI ICTD/O2 systems with separate fast temperature channels. 5 WHOI/FSI Ocean Temperature Modules (external platinum resistance thermometers) for redundancy on Mk-IIIb. 2 WHOI/FSI Ocean Conductivity Module for redundancy on Mk-IIIb. C.2.2. CTD Equipment Configuration Equipment used aboard Knorr for WOCE section I2 has been provided by both Woods Hole Oceanographic Institution CTD Operations, and the Scripps Institution of Oceanography's Shipboard Technical Services/ Ocean Data Facility (SIO STS/ODF). A total of 168 stations were taken during the cruise, which includes two test stations to check instrument performance. The underwater equipment was attached to an ODF-provided aluminum frame, capable of mounting thirty-six 10-liter bottles and a range of electronics. For this cruise two CTDs were usually used, along with a 36- position pylon, pinger, independent temperature modules and a lowered acoustic doppler current profiler (LADCP). Nearly all CTD data came from CTD-9, a WHOI-modified Neil Brown Mk-3b sampling at 23.8Hz, and incorporating a Sensormedics oxygen sensor assembly and a titanium pressure transducer with temperature sensor. Two early stations were taken with CTD-8, a General Oceanics-upgraded Mk3-c CTD. On most stations, one of two Falmouth Scientific (FSI) ICTDs were used in memory mode to provide an independent CTD trace. Both of the ICTDs provide 26Hz scan rate and Sensormedics oxygen sensors. Either can be configured for use in FSK mode to send data up the cable or in memory mode to internally record data and dump it at the end of a cast. Additionally, an FSI Ocean Temperature Module (OTM) was attached to each of the Mk-3 and ICTDs to give further temperature benchmarks. A General Oceanics (GO) model 1016-36 pylon and thirty-six ODF 10-liter bottles mounted in two concentric circles on the frame were provided by ODF. Also clamped into the frame were an Ocean Instrument Systems pinger for bottom-finding and an RDI LADCP and battery pack (see separate LADCP discussion). The underwater system was lowered from the Knorr's starboard Markey winch spooled with approximately 10,000 meters of Rochester 0.322 inch 3- conductor electromechanical cable. Standard lowering rates were 30 meters per minute to 200 meters wire out, and then 60 meters per minute to the target depth, as well as 60 meters per minute on the upcast. Significant backup equipment was available aboard but not used, including one spare 36-position frame complete with bottles from ODF, a WHOI-owned 25-position 4-liter bottle frame, two GO 1016-36 pylons, three GO 1015-24 pylons and two pingers. C.2.3. CTD Equipment Performance Of the 168 stations, 166 were taken with CTD-9, and two with CTD-8. The two FSI ICTDs took data on 137 stations, configured for internal recording and mounted on the frame at the same height as the Mk-3 to provide an independent CTD dataset. ICTD-1338 was used for 67 stations, and ICTD-1344 provided 70 stations. CTD-8 was not used further because of jumps in the multiplexed data channels, which resulted in unfittable data in the oxygen and pressure temperature channels. OTM data were integrated directly into the CTD data streams at the regular scan rate for that CTD. One OTM was replaced when it developed an intermittent output. Preliminary reviews have shown no obvious temperature shifts comparing the OTMs with either of the CTDs' temperature data. ICTD data were downloaded from the ICTD at the end of each station. Early problems maintaining connection to the downloading computer were traced to a faulty cable from the ICTD to the lab, and a replacement provided satisfactory performance. CTDs and OTMs used during the cruise are being returned to WHOI for post- cruise calibrations in WHOI's CTD Calibration Laboratory during early 1996. Power was maintained to the CTDs and pylon at all times to assure warmup conditions. Each of the three conductors of the seacable were used, one providing power and signal to/from the pylon, one for power and signal to/from the FSK mode CTD, and one providing power to the memory-mode CTD. The memory mode CTD was also provided with a backup battery in a pressure case to minimize the possibility of logging mode shutdown in the event of a power dropout. The starboard winch, wire and boom arrangement worked flawlessly. The seacable was reterminated approximately every 25 stations to avoid fatigue and corrosion failure, but in every case the wire was observed in apparently good to excellent shape at the termination. Retermination was not needed because of any cable problems. It should be noted that sea conditions were calm to moderate during the cruise. Winch operators were well-trained, attentive and proactive, making the CTD watch significantly smoother. Equipment provided by Scripps STS/ODF was in well maintained condition, and performed reliably during the cruise. There were occasional communications errors with the pylon traced to cross-talk from the CTD and pylon telemetry, but these were minor inconveniences. Special thanks go to the ODF group for their technical and logistics assistance and equipment support to WHOI in conducting this section as well as the I8S/I9S and I1 sections. C.2.4. CTD Data Acquisition and Processing Methods CTD data were acquired using a Neil Brown Instrument Systems Mk-III deck unit/display providing demodulated data to two personal computers running EG&G CTD acquisition software version 5.2 rev 2 (EG&G, Oceansoft acquisition manual, 1990). One computer provided graphical data to screen and plotter, the other provided a listing output. Two more personal computers were used, one for pylon control and one for recovering the data from the internal- recording ICTD. The pylon was driven by an ODF-provided pylon control system. Bottom approach of the CTD package was monitored by following the attached pinger's direct and bottom return signals on the ship-provided PDR trace. Following each station, the CTD data were forwarded to another set of personal computers running both EG&G CTD post-processing 5.2 rev 2 software and custom software from WHOI (Millard and Yang, 1993). The raw data were edited, pressure sorted, scaled and pressure centered into 2 decibar bins for final data quality control and analysis. A first pass fit of CTD salinity and oxygen to water sample salinity and oxygen was performed. C.2.5. CTD Calibration Summary C.2.5.1. Pre-cruise Laboratory Calibration: The pressure, temperature, and conductivity sensors of CTD-9, CTD-8, ICTD-1338 and ICTD-1344 were calibrated at the Woods Hole Oceanographic Institution's CTD Calibration Laboratory in November 1995 directly before the I2 cruise began. OTMs used during the cruise were also calibrated at that time. C.2.5.2. At-sea Pressure Correction: The pressure reading of the CTD before each station varied from 0.5 to 1.5 dbars on deck. To correct for this bias, the amount was subtracted from the pressure bias term so the calculated pressure read zero at the sea surface at the start of each station. C.2.5.3. At-sea Conductivity Calibration: The CTD conductivity data were fit to the water sample conductivity as described in Millard and Yang, 1993. CTD-9's conductivity sensor appeared quite stable. The sensor drifted 0.003 pss over the first 140 stations. C.2.5.4. At-sea Oxygen Calibrations: The CTD oxygen data were fit to the water sample oxygens to determine the six parameters of the oxygen algorithm (Millard and Yang, 1993). As with conductivity, the stations were fit when excessive drift in the sensor was noted. CTD-9's oxygen data, using the same six parameters to calculate oxygen show a drift of only 0.1 ml/l over the first 140 stations. C.2.6. Quality Control Notes For 2 Decibar CTD Data and .SEA Files Pressure difference: On deck difference in CTD-9's pressure between the start and end of cast was consistently close to 4.5 dbars. Comparing the pressure data with the ICTD logging in memory mode, it appears the 4.5 dbar change is occurring as the CTD is warming on the uptrace in the last few hundred meters. CTD-9 temperature and OTM-1326 difference: Difference in temperature at depth appears to have remained constant between these two instruments indicating there has been no temperature shift greater than 0.002oC since the OTM began collecting data on station 1090. Station 1078, CTD-8: The oxygen sensor assembly failed during downtrace at 875 dbar. Water had leaked into the assembly molding. Pressure temperature dropped 14oC, also at 875 dbars. While the oxygen data were not recoverable, the pressure temperature data were corrected by increasing the temperature after the drop by 14oC. The resulting corrected pressure temperature changed the calculated pressure by 5 dbars. Station 1079, CTD-8: The oxygen assembly from ICTD-1344 was put on to CTD-8, however oxygen current and oxygen temperature still did not look good. The oxygen data were unusable. Pressure temperature dropped again just at completion of the station. CTD-8 was removed from the package and replaced with CTD-9. Station 1090, CTD-9: OTM-1326 was connected to CTD-9 and successfully collected data through the end of the cruise. Stations 1100, 1101, 1102, CTD-9: Conductivity jumped low by 0.008 mmho during downtrace, most noticeably below 2.5oC potential temperature. Uptrace appeared fine. Station 1110, CTD-9: Conductivity drifted low by 0.005 mmho during downtrace, most noticeably below 2.5oC potential temperature. Station 1111 to 1174, ICTD-1338: ICTD-1338 was attached to package and successfully recorded and downloaded data from its internal memory. Station 1175 to end of cruise, ICTD-1344: ICTD-1338 was taken off package and replaced with ICTD-1344 and OTM- 1372 before station 1175 and used for the remainder of the cruise. C.3. Bottle Salinity Analysis A complete description of the salinity measurement techniques used during this cruise is presented in Knapp et al (1990). All measurements were made in a temperature controlled (23oC) van. The water sample salinities were collected by one of the CTD watch standers in 200 ml bottles with removable polyethylene inserts and caps. Bottles were rinsed three times, filled to the shoulder and securely capped. Samples were then allowed to reach laboratory temperature, and then measured with a Guildline Autosal Model 8400B salinometer (WHOI no. 11) that was standardized daily with IAPSO Standard Sea Water Batch P-128, dated 18 July 1995. Daily fluctuations of the Autosal standardization were usually less than 0.0002. Long-term drift of the instrument, from the beginning to the end of the cruise was approximately 0.001. The salinity measurements have an accuracy of 0.002. C.4. Dissolved Oxygen Analysis A complete description of the dissolved oxygen measurement techniques used during this cruise is presented in Knapp et al (1990). All measurements were made in a temperature controlled (23oC) van. Dissolved oxygen samples were also collected by a designated CTD watch stander from each watch. Aliquots of these samples were titrated within fourteen hours of collection. All oxygen reagents were prepared at WHOI in August, 1994, and loaded on the ship when she sailed from Woods Hole. A single batch of sodium bi-iodate standard was also prepared and loaded on the ship at that time. Post-cruise comparison of this standard will be made with a freshly prepared standard when the equipment returns to Woods Hole in March 1996, but based on comparisons made with oxygens measured on earlier legs of the expedition, it does not appear that this standard (17 months old at the end of the cruise) has deteriorated. Accuracy of these dissolved oxygen measurements is 0.5%. C.6. Nutrient Analyses C.6.1. Equipment and Techniques The analyses were performed using a Technicon AutoAnalyzer II (AAII) which is the property of Scripps Institution of Oceanography's Oceanographic Data Facility (ODF). This AutoAnalyzer has been used throughout the Indian Ocean WOCE Programme. A Keithley model 575 data acquisition system was used in parallel with analog stripchart recorders to acquire the absorbance data. The software used to process the nutrient data was developed at OSU. All of the reagent and standard materials were provided by OSU. The analytical methods are described in Gordon et al (1994). C.6.2. Sampling Procedures: Nutrient samples were drawn from all CTD/rosette casts at stations 1077 to 1244. High density polyethylene (HDPE) centrifuge tubes of approximately 50 mL volume were used as sample containers, and these same tubes were positioned directly in the autosampler tray. These sample tubes were routinely rinsed at least 3 times with one half to full volume of sample before filling. Sample tubes were rinsed twice with deionized water after sample runs, and were soaked in 10% HCl every other day. The nutrient samples were drawn following those for CFCs, helium, tritium, dissolved oxygen, carbon dioxide, alkalinity and salinity. At most stations, the AAII sample run was started before sampling was completed to reduce delay and minimize possible changes in nutrient concentration due to biological processes. C.6.3. Calibration and Standardization: Calibration standards for the nutrient analyses were prepared from high purity preweighed crystalline standard materials. The materials used were: Phosphate standard: J.T. Baker potassium di-hydrogen phosphate lot 3246. Nitrate standard: Alfa potassium nitrate lot 121881. Silicic acid standard: J. T. Baker sodium silicofluoride lot 21078 10A. Nitrite standard: MCB sodium nitrite lot 4205. The volumetric flasks and pipettors used to prepare standards were gravimetrically calibrated prior to the cruise. The Eppendorf Maxipettor adjustable pipettors used to prepare mixed standards typically have a standard deviation of less than 0.002 mL on repeated deliveries of 10 mL volumes. High concentration mixed standards containing nitrate, phosphate, and silicic acid were prepared at intervals of 7 to 10 days and kept refrigerated in HDPE bottles. For almost every station, a fresh "working standard" was prepared by adding aliquots of the high concentration mixed standard to low nutrient seawater. This working standard has nutrient concentrations similar to those found in Deep and Bottom waters. A separate nitrite standard solution was also added to these working standards. Corrections for the actual volumes of the flasks and pipettors were included in the preliminary data. The WOCE Operations Manual calls for nutrient concentrations to be reported in units of micromole/Kg. Because the salinity information required to compute density is not usually available at the time of initial computation of the nutrient concentrations, our concentrations are always originally computed as micromole/L. This unit conversion will be made using the corrected salinity data when it is available. Due to some problems with the nitrite analysis (see below), the nitrate values from station 1168 on reported in the .nut files include also nitrite. These values will be replaced later on after the appropriate correction is applied. C.6.4. Measurement of Precision and Bias: C.6.4.1. Short Term Precision and Bias: Throughout the cruise, replicate samples drawn in different sample tubes from the same Niskin bottle were analyzed to assess the precision of the AAII analyses. These replicate samples were analyzed both as adjacent samples (one after the other) and also at the beginning and end of sample runs to monitor deterioration in the samples or uncompensated instrumental drift. When the post cruise QC work is completed, these replicate analyses will be used to estimate short term precision and instrumental drift. C.6.4.2. Longer Term Precision: On most of the sample runs during I2, an "old" working standard from the previous station was run with the "new" working standard which had been freshly prepared. The "old" standards were kept refrigerated in plastic bottles. The average age of the "old" standards when reanalyzed was four to eight hours. The differences between these standards will be analyzed to assess the precision of standard preparation and handling and inter-station precision. C.6.5. Comparison with other data, long term precision and bias:. There were several crossings of other Indian Ocean WOCE lines along the I2 cruise track. Detailed comparisons with the nutrient data from these sections will be made after the post cruise QC work is complete. C.6.6. Nutrient Quality Control Notes: During the I2 cruise, no flagging of the nutrient data was performed, except for those bottles that were obvious leakers and for bottles whose values are average of two replicates. It is expected that during the post cruise QC work, questionable data can be corrected. In some stations the silicate analysis showed abnormally high values. These were due to an aberrant increase in the difference of the absorbance between the matrix (we use low nutrient seawater and distilled water, 25:1) and the distilled water reagent blank. The cause of this increase appears related to the presence of the surfactant used to decrease the noise in the absorbances and the sampler valving system. This actual process of this phenomenon is not clearly understood. However, it is possible to quantify the increase in values so a correction may be applied. There is an "ideal" LNSW-DDW value of ca. 12 absorbance units rather than the aberrant 20-40 we infrequently encountered. The nitrite analysis also showed problems. Beginning with station 1168, no nitrite values were reported. Artificially high values through the entire water column were obtained. Because those values do not really exist except for a couple near the surface, the subtraction of these values from the nitrite+nitrate analysis in order to get nitrate values would result in lower nitrate than the actual values. The nitrite correction will be reviewed at OSU and will be applied accordingly. C.7. CFC-11 and CFC-12 Analyses The transient tracers CFC-11 and CFC-12 were measured as a part of the overall program of measurements on WOCE leg I2. The technique to use CFC's to help describe ocean circulation is described in Gammon et al. (1981) and Bullister and Weiss (1983). C.7.1. Sample Collection Samples were collected at depth using 10 liter Niskin bottles. Aliquots of seawater were transferred to 100 cm^3 precision ground-glass syringes for the CFC analysis. Owing to the short length of time between legs I-10 and I-2 (3 days), cleaning of the Niskin bottles and o-rings was not necessary. All the 36 bottles in use remained outside on deck throughout the cruise. None of them showed CFC contamination during the cruise. C.7.2. Equipment and Methods Chlorofluorocarbons CFC-11 and CFC-12 were measured on a total of 158 stations. The analytical procedure is described by Bullister and Weiss (1988). Trapping is done on a length of 1/8 in. o.d. ss tubing packed with 5cm of Porasil C (80/100 mesh) and 5cm 0f Porapak T (80/100 mesh) cooled to -30oC using an ethanol bath cooled by a Neslab Cryocool. The trapped sample is desorbed using a 100oC water bath. A Shimadzu Mini-II GC is used to analyze the samples. It contains a 15cm precolumn and a 3m analytical column, both are 1/8 in o.d. stainless steel and are packed with 80/1 00 mesh Porasil C. Water samples are stored for analysis in a flow-through bath under clean sea water, after being drawn from the Niskin bottles. The analyses were completed typically within 5-10 hours of the sample collection, which is immediately after the CTD and rosette are brought on board. Air samples were run every 2 or 3 days from an air intake high up on the foremast and pumped from there to the lab van through a single length of Dekoron tubing using an Air Cadet diaphragm pump. C.7.3. Calibration Calibration curves used for determining CFC concentrations in air and water samples are generated by injection of various known volumes of standard gas. The calibration curves spanned the range of CFC concentrations in both the air and water samples. The standard is "clean" compressed air collected in the marine boundary layer and stored in Scott Aculife cylinders. The gas standard was calibrated at PMEL in Seattle WA. Intercalibrations of our standards have been carried out with other labs involved in WOCE. C.7.4. Data Data were reported as specified in the WOCE Operations Manual, WHP Office Report WHPO 91-1. Data were compared to historical data whenever possible. Historical data as well as real time observations were used as a guide for developing sampling strategies. C.8. Helium and Tritium Sampling During the I2 leg of WOCE Indian Ocean 370 helium/tritium sample pairs, one each helium and tritium taken from same bottle, were taken on 32 stations. The station spacing was approximately every 5 degrees of longitude along the 8oS line. The spacing was reduced to approximately every 1.5 degrees on the eastern and western boundaries and on the two short meridional lines near 88o & 72oE. These last two lines were sampled to further augment the overall spatial distribution of helium/tritium in the upper water column. The vertical distribution of the sampling was as follows: one station of 16 bottles sampled down to 1000m depth, followed by 8 bottle sampling down to a depth of 500m on the next helium/tritium station. On these same stations the deep helium sampling started where shallow helium/tritium ended to give complete helium profiles. This pattern of alternating 500m them 1000m samplings was carried out the whole length of the 8oS line including boundaries. The processing of the helium and tritium samples was carried out on board using "standard" high vacuum techniques. Both the helium extraction and the tritium degassing procedures involved using rotary mechanical pumps to achieve rough vacuum followed by diffusion pumping. The Varian pumps were charged with a poly phenyl ether based oil (Santovac 5), in conjunction with a cryogenic trapping of the water vapor. This procedure achieves pressures in the low to mid x10^-7 torr range. Once this starting pressure was reached on the all stainless steel vacuum system the samples were introduced into the system. The helium extraction was carried out using water vapor pumping as the means to strip and contain the helium sample until it could be sealed in a glass ampoule for storage. The tritum degassing system uses the same principle, water vapor pumping of the head space above the sample, stripping it of all gases, then shaking of the water sample to reequilibrate the head space. This procedure of stripping and reequilibration is repeated until head space pressure are in the low x10^-6 torr range. At this point the remaining degassed water sample is sealed in a glass bulb for storage. The helium and tritium samples are then transported back to the Helium Isotope Laboratory at the Woods Hole Oceanographic Institution for analysis by mass spectrometry. C.9. Deep Helium Sampling Report C.9.1 Sampling Eight hundred and sixteen deep helium samples were collected from Niskin bottles in stainless steel cylinders which are approximately 40 ml in volume. A total of 53 stations were sampled, spaced two degrees apart, with one degree spacing across spreading zones and through flow areas. Sixteen samples were taken at each station in an array between 1000 meters depth and the bottom of the cast. In some cases the sea floor was too shallow to permit sixteen samples, so all bottles fired in the given interval were sampled. C.9.2 Sample preparation methods Each water sample was stripped of dissolved gases using both high and ultra high vacuum technologies. A rotary pump was used to create the initial high vacuum (approximately 5.0 E-3 torr) and an oil diffusion pump using Santovac 5 (pentaphenyl ether) was used to create the ultra high vacuum (approximately 5.0 E-7 torr). A "water vapor pump" was created by applying a temperature gradient of 100 degrees across the evacuated space. The dissolved gases were pumped into glass ampoules and held there by the resulting pressure gradient until the ampoules were closed by flame sealing. The ampoules are being shipped back to the Lamont-Doherty Earth Observatory for analysis by mass spectrometer. C.10. Radiocarbon Sampling The Princeton University Ocean Tracers Lab was responsible for collecting samples for carbon 14 analysis on WOCE line I2. The data from this line together with data from the far western Pacific and other WOCE Indian Ocean lines will be used to characterize the water masses at particular points of interest. Such points include mapping the through flow of the deep boundary current along the 90oE Ridge, the deep flow around 3o 00'S across the Chagos-Laccadive Ridge and a mapping of the northern branch of the South Equatorial Current. This was a detailed leg and other locations were documented as well. Six hundred and fifty five samples were collected at 29 stations on this line. Full water profiles were collected at 14 stations; shallow profiles, 1800m or less, were collected at 15 stations. The samples will be analyzed at a later date in the land based Atomic Mass Spectrometry lab at Woods Hole Oceanographic Institution. C.11. Radium Sampling As a side project the Princeton University Ocean Tracers Lab has been collecting surface samples at various stations along the I2 track for analysis of radium 226 and 228. Samples are collected on stations of depths greater than 2500m to give the fiber, for 228 measurement, time to soak. Samples are collected about once a day if they are deep enough. The method for collection is as follows. For the surface soak, fiber is placed in a flow through, netted, cloth bag and cast over the side attached to a string on the ship. It soaks for the duration of the station and is then brought up, placed in a baggie, which is labeled and stored for shipment back to the Ocean Tracers Lab for processing and analysis. This is a large volume sample. Small volume samples are placed in 7 x 3/4 inch clear plastic tubes. A 25 liter jug with a spigot is then filled with surface water collected with a bucket cast over the side. The fiber tube is attached to the spigot with a flexible tube and the water in the jug is trickled through the fiber over an 8 to 12 hour period. When this is done this sample is also placed in a baggie, labeled and stored for shipment back to the lab. For LV (large volume) samples the fiber is leached and formed into a precipitate which is put into a small tube and measured in a gamma counter. SV samples are measured on a radon board by forcing gas through and measuring decay counts in special cells with photaic properties. The fiber is actually acrylic fiber that has been "cooked" at 100o C in potassium permanganate. The radium attaches to the manganate, and thus the reason long soaking times are needed. About 30 samples each of SV and LV were collected on I2 for later analysis back at Princeton. C.12. Total CO2 and Alkalinity Analyses C.12.1 Overall Objective: Documentation of the CO2 partial pressure, total inorganic carbon content and alkalinity of the ocean to discern the forces modulating rise in atmospheric CO2. These parameters were measured in conjunction with the overall program of measurements for the WOCE I2 leg. C.12.2 Sample Collection: Documentation of the CO2 partial pressure, total inorganic carbon content and alkalinity of the ocean to discern the forces modulating rise in atmospheric CO2. These parameters were measured in conjunction with the overall program of measurements for the WOCE I2 leg. C.12.3 Equipment and Methods: Total inorganic carbon (TCO2) and total alkalinity (TA) were measured on a total of 166 stations (75 full profiles/91 surface). A total of 3001 samples were analyzed for TCO2 (including replicates). A total of 3070 samples were analyzed for TA (including replicates). The analytical techniques employed are described in Dickson and Goyet (1994). A short description is as follows: TCO2- A known amount of seawater is dispensed into a stripping chamber, where it is acidified and purged with an inert gas. This gas stream is coulometrically titrated and compared to known amounts of CO2 gas. The final concentration is expressed in micromole/Kg of seawater. TA- A known amount of seawater is placed in a closed, thermostated, titration cell and titrated with a solution of hydrochloric acid. The titration is monitored by using a glass electrode/reference electrode and a non-linear least squares approach is applied to the resultant e.m.f. data. The final concentration is expressed in micromole/kg of seawater. C.12.4 Data: Data were reported as specified in the WOCE Operations Manual, WHP Office Report WHPO 91-1. Internal Data Quality Indicators incorporated into the sampling plan included field replicates and Certified Reference Materials. Review of these data indicated that the instrumentation performed within acceptable control limits throughout the cruise. The few minor instrumentation difficulties encountered during the cruise were quickly fixed and did not impact our ability to adhere to our original sampling/analysis scheme. D. Acknowledgments We are indebted to the officers and crew of R/V Knorr for their good- natured and unflagging support for the scientific work on the I2 leg of the WOCE Hydrographic Program Indian Ocean Expedition. The good spirit of the entire ship's company throughout this long voyage contributed greatly to making it such a pleasant and successful one. E. References Bullister, J. L. and R. F. Weiss. 1983. Anthropogenic chlorofluoromethanes in the Greenland and Norwegian Seas. Science, Vol. 221, pp. 265-268. Bullister, J. L. and R. F. Weiss. 1988. Determination of CCl3F and CCl2F2 in sea water and air. Deep-Sea Research, Vol. 35, No. 5, pp. 839-853. Dickson, A.G. and C. Goyet. 1994. Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water, Ver.2. DOE. Fisher, J. and M. Visbeck. 1993. Deep velocity profiling with self-contained ADCPs. J. Atmos. Oceanic Technol., 10, 764-773. Gammon, R. H., J. D. Cline and D. P. Wisegarver. 1981. Chlorofluoromethanes in the Northeast Pacific Ocean: measured vertical distributions and application as transient tracers of upper ocean mixing. Journal of Geophysical Research, Vol. 87, pp. 9441-9454. Gordon, L. I., J. C. Jennings, Jr., A. A. Ross and J. M. Krest. 1994. A suggested protocol for continuous flow automated analysis of seawater nutrients (phosphate, nitrate, nitrite and silicic acid) in the WOCE Hydrographic Program and the Joint Global Ocean Fluxes Study. In WOCE Operations Manual, WOCE Report No. 68/91. Revision 1, 1994. Knapp, G. P., M.C. Stalcup & R.J. Stanley. 1990. Automated Oxygen Titration and Salinity Determination. Woods Hole Oceanographic Institution Tech. Rep. WHOI-90-33, 25 pages. Millard, R. C. and K. Yang. 1993. CTD Calibration and Processing Methods Used At Woods Hole Oceanographic Institution. Woods Hole Oceanographic Institution Tech. Rep. WHOI-93-44, 96 pages. Oceansoft MKIII/SCTD Acquisition Software Manual. 1990. P/N Manual 10239. EG&G Marine Instruments. WHPO, 1991 WOCE Operations Manual. WHP Office Report WHPO 91-1 WOCE Report No 68/91. Woods Hole Mass, USA. F. Figure Captions Figure 1. WOCE Hydrographic Program Section I2 station locations (dots) with the 3000m isobath. Every fifth station number is shown for clarity. Figure 2. Vertical section of bottle positions for WOCE Hydrographic Program Section I2. Vertical exaggeration is 750:1. the longitude locations (oE) are plotted parametrically along the bottom axis. The station locations are plotted parametrically along the top axis. the bathymetry is plotted only at station locations.