| Contributors | Affiliation | Role |
|---|---|---|
| Smith, Walker O. | Virginia Institute of Marine Science (VIMS) | Principal Investigator, Contact |
| Friedrichs, Marjorie A.M. | Virginia Institute of Marine Science (VIMS) | Co-Principal Investigator |
| Heywood, Karen J. | University of East Anglia (UEA) | Co-Principal Investigator |
| Gegg, Stephen R. | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
These results were published in:
Kaufman et al. (2014): peer-reviewed paper describing the project and the physical-biological results.
Smith et al. (2014): peer-reviewed paper describing the results in conjunction with other ongoing projects in the area.
Quest et al. (2015): peer-reviewed paper describing the results of the oxygen dynamics.
All of the above have maps showing the study area and data.
Latitude and longitude (parameter names lat and lon) were measured at the surface and linearly interpolated when the glider was at depth. Parameter name GPS value id indicates measurements while glider was at the surface (value = 1) or interpolated while diving (value = 0). No interpolation or smoothing was performed on other data.
Temperature and salinity (parameter names temp and sal): Temperature and salinity data were calculated using pre deployment calibration coefficients. A first-order lag correction was applied to raw measurements of temperature and conductivity (due to temperature latency). For each dive, out of range measurements and spikes (3 interquartile ranges above or below the median in windows of 15 contiguous measurements) were flagged and replaced with NaNs, which were repopulated by linear interpolation. Data were smoothed with an 11-point median filter. Parameters potemp and sigma_0 were calculated from the smoothed temp and sal datasets.
Dissolved oxygen, O2 (parameter name O2_cal): Oxygen data from the Aanderaa optode were corrected for time lags in oxygen and temperature. The resulting oxygen has an error of ±2 µmol kg-1.
Particulate backscattering coefficients, bbp (parameter names bbp470, bbp700): Backscattering digital counts were converted to at 117° by subtracting factory-provided dark counts and β multiplying by factory calibration scale factors.
Particulate organic carbon (POC) derived from bbp(700) (parameter name POC_bbp): The regression to convert ship downcast bbp at 700 nm to POC is: POC (mg C m-3) = 19607*bbp700 + 17.621; R2 = 0.85, p < 0.01. Because all backscatter sensors were cross calibrated with the ship CTD downcast, this regression was directly applied to glider bbp at 700 nm to compute glider POC.
Chlorophyll fluorescence (parameter names chl_raw): Chlorophyll fluorescence measured by glider ECOPuck BB2F was calibrated with discrete chlorophyll samples taken from calibration profiles. The regression was CHL = (FL -141)*0.00225 (R2 = 0.94, p < 0.01).
Data Processing: All data were analyzed for peaks and lost data, and if unexplained values were recorded, replaced by a smoothed average from +/- ten points above and below the spike. Sigma-T values are calculated using standard algorithms.
BCO-DMO Processing Notes
- Generated from original file: "SG502.csv" contributed by Walker Smith
| File |
|---|
GOVARS_SG502.csv (Comma Separated Values (.csv), 55.02 MB) MD5:aa4e9d4fa1cac6d22566bc6659672637 Primary data file for dataset ID 532608 |
| Parameter | Description | Units |
| dive_id | dive identification number | dimensionless |
| date | date (UTC) start of sampling | YYYYMMDD |
| julian_day_yr0 | time when sample was taken in decimal days since Jan-0-0000 | dimensionless |
| lat | latitude (South is negative) | decimal degrees |
| lon | longitude (West is negative) | decimal degrees |
| GPS_id | GPS value id; measurement taken while on surface (value=1) or interpolated while diving (value=0) | integer |
| depth | depth at which sample was taken | meters |
| temp | Temperature | degrees Celsius |
| potemp | Potential Temperature | degrees Celsius |
| sal | Salinity | dimensionless |
| sigma_0 | potential density minus 1000 | kilograms/meter^3 |
| O2_cal | dissolved oxygen concentration measured from Aanderaa Optode 3830 oxygen sensor | micromol/kilogram |
| POC_bbp | particulate organic carbon from bbp(700); based on POC and bbp(700) measurements | milligrams/meter^3 |
| bbp470 | particulate backscattering coefficient at 470 nm; bbp(470) from ECOPuck BB2F;based on factory calibrations | β(θc) /m /sr |
| bbp700 | particulate backscattering coefficient at 700 nm; bbp(700) from ECOPuck BB2F; intercalibrated with KN19303 bbp(700) measurements | (θc) /m /sr |
| chl_raw | chlorophyll fluorescence (raw output minus dark counts) | milligrams/meter^3 |
| Dataset-specific Instrument Name | Aanderaa Oxygen Optodes |
| Generic Instrument Name | Aanderaa Oxygen Optodes |
| Generic Instrument Description | Aanderaa Oxygen Optodes are instrument for monitoring oxygen in the environment. For instrument information see the Aanderaa Oxygen Optodes Product Brochure. |
| Dataset-specific Instrument Name | Druck PDCR 4020 |
| Generic Instrument Name | Druck PDCR 4020 pressure sensor |
| Generic Instrument Description | The PDCR 4000 Series provides a complete range of mV output pressure transducers offering advanced levels of measurement accuracy stability and flexibility from a standard production device. |
| Dataset-specific Instrument Name | Seaglider |
| Generic Instrument Name | Seaglider |
| Generic Instrument Description | The Seaglider is an autonomous underwater vehicle developed through a collaboration between The Applied Physics Laboratory -University of Washington and the University of Washington School of Oceanography. These small, free-swimming vehicles can gather conductivity-temperature-depth (CTD) data from the ocean for months at a time and transmit it to shore in near-real time via satellite data telemetry. Seagliders make oceanographic measurements traditionally collected by research vessels or moored instruments. They can survey along a transect, profile at a fixed location, and can be commanded to alter their sampling strategies throughout a mission. |
| Dataset-specific Instrument Name | Wet Labs ECO Puck BB2F-VMG |
| Generic Instrument Name | Wet Labs ECO Puck BB2F-VMG |
| Generic Instrument Description | The ECO BB measures scattering at 117 degrees, the angle determined as a minimum convergence point for variations in the volume scattering function (VSF) induced by suspended materials and water itself. As a result, the signal measured by this meter is less determined by the type and size of the materials in the water and is more directly correlated to the concentration of the materials. Conversely, the meter provides unparalleled accuracy for any single-angle measurement in determining the optical backscattering coefficient: an important parameter for remote sensing and in many in-water bio-optical applications. |
| Website | |
| Platform | iRobot Seaglider |
| Start Date | 2010-11-22 |
| End Date | 2011-01-20 |
| Description | Southern Ross Sea, bounded by -77.436° and 169.517E°, and extending to -76.3403° and 180°; the glider made two long transects near the 76.5° line from the eastern side of the Ross Sea polynya to the dateline, and back; recovery was by the NB Palmer |
Extracted from the NSF award abstract:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
The Ross Sea is a highly productive area within the Southern Ocean, but it experiences substantial variability in both physical (temperature, ice concentrations, salinity, winds, and current velocities) and biogeochemical (chlorophyll, productivity, micronutrients, higher trophic level standing stocks, gases, etc.) conditions. Understanding the temporal and spatial oceanographic variations in physical forcing is essential to understanding the ecological functioning within the Ross Sea. There are a number of models of the physical oceanography of the Ross Sea that characterize the observed circulation. Unfortunately, data on the appropriate time scales (daily, monthly, seasonal, and interannual) to completely evaluate those models are lacking. The proposed research is a demonstration project to characterize the physical and biological oceanography of the southern Ross Sea using newly developed Glider technology to sample the region continuously through the growing season, to collect temperature, salinity, fluorescence, oxygen and optical transmission data. These field data will be used to assist in evaluation of an eddy-resolving ROMS-based coupled circulation-biological model, and, along with satellite ocean color information, will be assimilated into an ecosystem model. Data assimilation techniques will reduce the model uncertainties of the circulation and food webs of the region. The intellectual merit of this effort arises from the combination of field-based investigations using a novel technology (one that is far more cost-effective than ship-based studies) with state-of-the-art biological-physical models and advanced data assimilation techniques. The research will provide new insights into the complex oceanographic phenomena of the Antarctic continental shelves and is a novel method of continuing the studies of the southern Ross Sea. Broader impacts of the proposed research include training of graduate and undergraduate students and partnership with several ongoing outreach programs dealing with scientific research in the Southern Ocean. At least 2 graduate students will be supported by this research, and it will be a critical component of a variety of outreach programs in Virginia, including a High School Marine Science Day, Boy and Girl Scout education, and middle school curriculum improvement. The investigators also will create a web site to foster immediate release of the data collected by the glider, and seek a linkage with schools at various levels (middle, high school and Universities) that potentially could incorporate the data into classroom activities
Related files:
1. Kaufman et al. (2014): peer-reviewed paper describing the project and the physical-biological results (kaufman et al. 2014 DSR.pdf)
2. Smith et al. (2014): peer-reviewed paper describing the results in conjunction with other ongoing projects in the area (smith et al. 2014 oceanogr.pdf)
3. Quest et al. (2014): peer-reviewed paper (in press) describing the results of the oxygen dynamics (quest et al. 2014 ant sci.pdf)
| Funding Source | Award |
|---|---|
| NSF Antarctic Sciences (NSF ANT) |