SCruise Report R/V Roger Revelle Cruise RR0901 10 January 2009 to 24 February 2009 Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean DIMES Cruise US1 Deployment Cruise Chief Scientist James R. Ledwell Woods Hole Oceanographic Institution [email protected] Brian Guest, Leah Houghton, and Cynthia Sellers Woods Hole Oceanographic Institution Stewart C. Sutherland Lamont-Doherty Earth Observatory Peter Lazarevich and Nicolas Wienders Florida State University Ryan Abernathey and Cimarron J. L. Wortham Massachusetts Institution of Technology Byron Kilbourne University of Washington Magdalena Carranza and Uriel Zajaczkovski University of Buenos Aires Jonathan Meyer and Meghan K. Donohue Scripps Institution of Oceanography 2 November 2012 Acknowledgements Captain David Murline and the crew of R/V Roger Revelle provided excellent and steadfast support during this cruise. The marine operations and science support groups at Scripps Institution of Oceanography were thorough, professional and helpful, especially Jonathan Meyer and Meghan Donohue, the marine technicians on the cruise. Lawrence Anderson, Valery Kosneyrev, and Dennis McGillicuddy at the Woods Hole Oceanographic Institution helped enormously by calculating and sending estimates, including animations, of sea surface height from AVISO satellite altimetry data. Marjorie Parmenter, also of Woods Hole Oceanographic Institution, provided editorial assistance for this report. Funding for the project is from the National Science Foundation, Grants OCE 0622825 and OCE 1232962. ii Cruise Report R/V Roger Revelle Cruise RR0901 10 January 2009 to 24 February 2009 Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean DIMES Cruise US1 Deployment Cruise iii This page intentionally left blank iv Table of Contents Acknowledgments ............................................................................................................. ii 1. Introduction ....................................................................................................................1 1.1 Objectives ..................................................................................................................1 Fig. 1.1.1. Neutral density at 105°W from WOCE Section P18 ..................................1 2. Cruise Narrative .............................................................................................................2 2.1. Underway Measurements .......................................................................................2 Table 2.1.1. Underway Data Streams ...........................................................................2 2.2. Mooring Deployments .............................................................................................2 Fig. 2.2.1. Cruise track and operations .........................................................................3 2.3. Front Identification .................................................................................................3 Fig. 2.3.1. Absolute Dynamic Topography (ADT) Map ..............................................4 Fig. 2.3.2. XBT profiles from north and south of the Polar Front ................................5 2.4. CTD/ADCP Line .....................................................................................................5 Fig. 2.4.1. Absolute Dynamic Topography (ADT) along 105oW ................................6 Fig. 2.4.2. Neutral density and zonal geostrophic velocity sections ............................7 2.5. XBT Series ...............................................................................................................7 Fig. 2.5.1. Temperature profiles from 50oS to 58oS along 105oW ...............................8 Fig. 2.5.2. Location of XBT drops ...............................................................................9 2.6. RAFOS Deployments ..............................................................................................9 2.7. Surface Drifters .......................................................................................................9 2.8. Medical Evacuation - End of Leg 1 ........................................................................9 2.9. Tracer Release .......................................................................................................10 Table 2.9.1. Injection Statistics ..................................................................................10 Fig. 2.9.1. Tracer injection and sampling tracks ........................................................11 2.10. Shearmeter Floats ...............................................................................................11 2.11. EM-APEX Floats .................................................................................................12 2.12. CTD Box Survey around the Tracer Patch ......................................................12 Fig. 2.12.1. CTD stations and geostrophic velocity at 1500 dbar ..............................13 Fig. 2.12.2. Geostrophic surface velocity ...................................................................14 2.13. Surveying of the Tracer Patch ...........................................................................14 v Fig. 2.13.1. Tracer concentration versus height; CTD Cast 38 ..................................15 Fig. 2.13.2. Sampling Array .......................................................................................16 Fig. 2.13.3. Time series of temperature from the sampling array ..............................17 Fig. 2.13.4. Tracer profiles from sampler Tows 1, 2, and 3 .......................................18 Fig. 2.13.5. Tracer transects from the 50-chamber sampler .......................................19 Fig. 2.13.6. Mean tracer concentration as a function of σ1500 ....................................20 Fig. 2.13.7. Mean depth as a function of σ1500 ...........................................................20 Fig. 2.13.8. Mean tracer profile as a function of depth ..............................................21 2.14. Initial Diapycnal Distribution of the Tracer Patch ..........................................21 Table 2.14.1. Statistics of the Initial Tracer Distribution ...........................................22 2.15. CTD Calibrations ................................................................................................22 2.16. Cruise Time Line .................................................................................................22 3. Meteorological and Surface Seawater Measurements ..............................................23 3.1. Location of the Instruments .................................................................................23 Fig. 3.1.1. R/V Roger Revelle portside plot ...............................................................23 3.2. Description of the Sensors ....................................................................................23 Table 3.2.1. Meteorological and Underway Seawater System Sensor Specifications .............................................................................28 Table 3.2.2. Surface Seawater Sensors .......................................................................29 Table 3.2.3. Meteorological Sensors ..........................................................................29 3.3. Data Processing and Results ................................................................................30 Fig. 3.3.1. Barometric Pressure, Wind Speed, and Direction at the MET mast, 12–21 Jan 2009 .........................................................................................32 Fig. 3.3.2. True Wind Speed at the MET and Main masts, 12 Jan–20 Feb 2009 .......32 Fig. 3.3.3. True Wind Direction at the MET and Main masts, 12 Jan–20 Feb 2009 .33 Fig. 3.3.4. Air Temperature at the MET mast and with the RH module, 12 Jan–20 Feb 2009 ..................................................................................33 Fig. 3.3.5. Air Temperature and Relative Humidity at the MET mast, 12–25 Jan 2009 .........................................................................................34 Fig. 3.3.6. Dew Point and Precipitation at the MET mast, 12–20 Jan 2009 ..............35 Fig. 3.3.7. Long and Short wave radiation records, 12–25 Jan 2009 .........................36 Fig. 3.3.8. Flow rates in TSG #1 and #2, 12 Jan–20 Feb 2009 ..................................37 vi Fig. 3.3.9. Surface Temperature measured in TSG #1 and #2, 12 Jan–20 Feb 2009 .................................................................................37 Fig. 3.3.10. Surface Salinity measured in TSG #1 and #2, 12 Jan–20 Feb 2009 .......38 Fig. 3.3.11. Temperature and Salinity from the CTD at 4 m minus SST and SSS from TSG #1 .............................................................................38 Fig. 3.3.12. Surface Temperature, Surface Salinity, and σt from TSG #1, 12–25 Jan 2009 .......................................................................................39 Fig. 3.3.13. Surface Temperature recorded at TSG #1 along the ship’s track ...........40 Fig. 3.3.14. Surface Salinity derived from TSG #1 along the ship’s track ................40 Fig. 3.3.15. O2, O2 Saturation, Chl, and Surface PAR, 12–25 Jan 2009 ....................41 3.4. Guide to Underway Data and Processing Software ...........................................41 4. Hull Mounted Acoustic Doppler Current Profilers (ADCPs) ..................................43 4.1. RDI 150 kHz Narrowband ADCP .......................................................................43