ACE-1 R/V DISCOVERER STATUS FORM

DATE/TIME: (95112819)

PREPARED BY: Tim Bates

• LOCATION PRESENT: LATITUDE: 41 17.7S LONGITUDE: 143 11.0E
• LOCATION -6 HOURS: LATITUDE: 41 10.2S LONGITUDE: 143 12.8E
• LOCATION -12 HOURS: LATITUDE: 41 04.1S LONGITUDE: 143 18.4E
• LOCATION -18 HOURS: LATITUDE: 41 02.3S LONGITUDE: 143 19.2E

PRESENT WEATHER:

Winds 335 degrees at 12 m/s, pressure 1000.3 and falling, partly cloudy, dry bulb 13.2C, wet bulb 11.2C seawater 12.7C.

SEA STATE:

West southwesterly 3-4 M swell, wind waves from 335 at 2-3M

INSTRUMENTS/SYSTEMS STATUS

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• Sea Surface Measurements:

  1. DMS: Seawater DMS concentrations south of 42S are still relatively low (1nM+-0.5). The concentrations measured near Macquarie were typical of winter values in mid to high latitudes (0.5nM). In the region near Southern Surveyor station P1 DMS concentrations range from 2-3 nM. Concentrations are again lower at the coastal station (CG-1) (0.8-1.6). We should probably pick an average clean sector trajectory from Cape Grim and transit out roughly 360 nautical miles (nm) to get a one-day (24hr x 15 knots) trajectory upwind of the cape of surface DMS concentrations. Any suggestions as to the trajectory
  2. DMSP/DMSO: Samples collected every 8 hours for particulate and dissolved DMSP and DMSO.
  3. NH4+NH3/pH: NH4+NH3 concentration 0.5 umolar. pH 8.09.
  4. CO: Surface seawater concentrations have a diurnal cycle with a late night minimum of 0.6 and and an afternoon maximum of 1.3 nM.
  5. NMHC: Butane ~5ppb; Pentane ~0.4ppb in equilibrated air samples.
  6. CO2:
  7. Nitrate/Chlorophyll: Nitrate concentrations are approximately 0.2 uM. Seawater fluorescence is being recorded continuously. Surface seawater samples are being collected every 4 hours for discrete chlorophyll analysis.

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• Atmospheric Measurements:

  1. DMS: DMS concentrations south of Tasmania have generally ranged from 40-120 ppt with a few higher values. With the constantly changing meteorological conditions there has been no clear indication of a diurnal cycle in DMS concentrations. In the area west of Tasmania, atmospheric DMS concentrations have ranged from 50-250 ppt, with higher concentrations during periods of WNW winds and lower concentrations during periods of SW or N winds. We would like to find a time/region of relatively high seawater DMS concentrations and a consistent wind direction to look at DMS/SO2/sulfate diurnal cycles but have not yet had that opportunity. Never fear, we still have two weeks left.
  2. SO2: Concentrations range from 10-25ppt.
  3. NH3: Using oxalic acid coated filters. Concentrations measured with oxalic acid coated filters range from 3 to 10 pptv.
  4. CO: Concenctrations near 60ppb.
  5. NMHC: Butane ~300ppt; Pentane ~30ppt
  6. O3: Concentrations range from 20-24 ppb.
  7. Nitrogen oxides and PAN: NO up to ~80 ppt and NOy ~1800 ppt (preliminary values) in am. NO2 not operational.
  8. Radon:
  9. CO2:
  10. Solar Radiation:
  11. Aerosol physics: NW air stream, "open" size distribution, modes at 14, 30 and 110nm . UFCN = 800, CN = 750 pp/cc
  12. Aerosol chemistry: 2-stage and 7-stage impactors currently sampling for time periods ranging from 24 to 72 hours for IC, total organic carbon, speciated organics, and gravimetric analysis.
  13. Aerosol optical properties:
  14. TDMA-RH: Results from 11/27 showed low growth factors (1.5) due to air coming from the Australian continent. The particle production event in the morning of the 28th may be difficult to see because of the pollution.
  15. TDMA-Thermal:

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• ISS Status and Schedule:

  ISS status report for ACE-1 for today is here

  System operational with 4 sondes/day. An extra sonde was launched at 1400 to support aircraft operations.

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• Routine Weather Observations: Going well.
• Satellite Observations: None
• CTD Cast Schedule: A cast is scheduled for 2200.

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• SPECIAL PLANNED OBSERVATIONS (NEXT 24-HOURS):

  Return to and hold station (GC1) 20 nm from Cape Grim for air and surface seawater sampling and intercomparison with Cape Grim.

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• PAST 24-HR OPERATIONS SUMMARY: Helicopter operations to transport a transponder ashore were successful. After helicopter operations the ship steamed southwest to reach the frontal system. Subsidence of ultra-fine partilces was evident after the fronal passage. The ship held station in the clear air after the front for air and surface seawater sampling.
• OTHER COMMENTS: We have not received status reports from the other platforms for the past two days.