R/V OCEANUS Athena metadata file Tue 25/May/2004 01:25:53 Current time zone: GMT Standard Time ============================== 12kHz depth ( Depth12) Format: Depth (meters) Depth in meters obtained from the 12 kHz channel of the Knudsen bathymetry system. 5 meter depth of transducer has been applied. __________________________________________________ 3.5kHz depth ( Depth35) Format: Depth (meters) Depth in meters obtained from the Knudsen 3.5 kHz channel. 5 meter transducer depth correction has been applied. __________________________________________________ Sea Surface Conductivity (SSCND) Falmouth Scientific TSG (OCM-S-212) sea surface conductivity Format: Conductivity (mmho/cm or milli-Siemens/centimeter) OCM sensor is mounted in the bow thruster room on the suction side of the clean sea water distribution pump. Sea water intake is from a bow inlet pipe located 12 feet below the waterline. Calibration - 05/11/2002 Installation - 01/03/2003 __________________________________________________ Sea Surface Temperature (SSTMP) Falmouth Scientific TSG (OTM-S-212) sea surface conductivity (degrees C) Format: Sea surface temperature OTM sensor is mounted in the bow thruster room on the suction side of the clean sea water distribution pump. Sea water intake is from a bow sea chest located 12 feet below the waterline. Calibration - 20/08/2002 Installation - 01/2003 __________________________________________________ GPS course over ground (GPS_COG) Course over ground (true) obtained from NMEA GPS_VTG data sentence. Format: Course __________________________________________________ Latitude (GPS_Lat) Latitude from GPS NMEA GGA data sentence formatted for display. Format: dd mm.sss, N/S __________________________________________________ Longitude (GPS_Lon) Longitude from GPS NMEA GGA data sentence formatted for display. Format: ddd mm.sss, E/W __________________________________________________ GPS Navigation data (GPS) Complete NMEA data output from the primary GPS receiver. The datum used by both the P-Code and Northstar GPS receivers is WGS84. The single digit following the position information in the GPS_GGA data string indicates the type of GPS fix as follows: 0=No valid fix; 1=Standard; 2=Differential; 3=P-Code NMEA GPS_GGA data sentence: Header , UTC of position, Latitude, N/S, Longitude, E/W, Quality indicator, Number of satellites in use, Horizontal dilution, Altitude, M (meters), Geoidal seperation, M (meters), Age of differential data (secs), Differential reference station I.D. * checksum. (Lat & Lon values are "degrees minutes.decimal_minutes") NMEA GPS-VTG data sentence: Header, Course, T (degrees true), Course, M (magnetic), Speed, N (knots), Speed, K (km/hr) * checksum. __________________________________________________ GPS speed over ground (GPS_SOG) Speed over ground (knots) obtained from NMEA GPS_VTG data sentence. Format: Speed __________________________________________________ GPS type (GPS_TYPE) GPS position type (Std, Diff, P-Code) GPS position type indicator is obtained from the "quality indicator" included as part of the GPS NMEA GGA data sentence. __________________________________________________ Gyro heading (Gyro) Ship's heading (degrees true) obtained from the Gyro NMEA HEHDT data sentence. Format: Heading (degrees true) __________________________________________________ IMET Wind (IMET_WND) Format: X, Y, Total, Max, Min, LastVane, LastCompass, C1, C2 Wind X (m/sec), Positive for a stbd to port wind Wind Y (m/sec), Positive for a bow to stern wind Wind Total (m/sec), Averaged over previous minute Wind Max (m/sec, 15 sec interval), Wind Min (m/sec, 15 sec interval), Last Vane Reading (deg), Last Compass Reading (deg), Counter1 ("0"), Counter2 ("4") Note - Wind direction is not provided as a single quantity. Direction values are ship relative. The wind sensor does not have a compass installed (value should always be 0.0). Calibration - Jan 2003 __________________________________________________ IMET Air Temperature (Air_Temp) Format: Temp (C) Data is obtained from IMET_HRH primary sensor. __________________________________________________ IMET Barometric Pressure (IMET_BPR) Format: Barometric pressure (milli-bars) Calibration - Jan 2003 __________________________________________________ IMET Precipation (IMET_PRC) Format: Precipitation (millimeters) Last minute (mm/min) Last hour (mm/hr) Present level (mm) Calibration - Jan 2003 __________________________________________________ IMET relative humidity (HRH) Format: Humidity (%RH) Data is obtained from IMET_HRH primary sensor. __________________________________________________ IMET Shortwave Radiation (IMET_SWR) Format: Radiation (watts/square meter) Calibration - Jan 2003 __________________________________________________ IMET Humidity (IMET_HRH) Format: Humidity (%RH), Temperature (C) Note - IMET humidity and air temperature data are both obtained from this instrument. Calibration - Jan 2003 __________________________________________________ Knudsen bathymetry ( PKEL99) Depth data obtained from the Knudsen bathymetry system. Values have been corrected for transducer depth (5 meters). Format: Header ($PKEL99), 12 kHz depth (meters), 3.5 kHz depth (meters), Speed of sound (m/s), Lat (dd mm.mmm N/S), Lon (ddd mm.mmm E/W) __________________________________________________ NMEA Gyro (HEHDT) Ship's heading obtained from the Sperry Gyro. NMEA format: Header ($HEHDT), Heading (degrees), T (true), Heading (degrees), M (magnetic) * checksum. Version 2.20 (1/1/97) of the NMEA 0183 standard does not show magnetic heading in this data sentence and the validity of this item is questionable. __________________________________________________ Position from GPS receiver (Lat_Lon) Latitude & Longitude in decimal degrees. Format: +/- dd.dddddd +/- ddd.dddddd (N & E are "+") __________________________________________________ SBE21 Temp & Cond ( SBE21_TC) Temperature - degree C (-5 to +35, +/- 0.01) Conductivity - mmho/cm (0 to 70, +/- 0.01) 1 Siemens/meter = 10 mmho/cm __________________________________________________ SBE21 conductivity ( sbe21cnd) Format: dd.ddd mmho/cm (0-70, +/- 0.01) Based on ITS90 temperature calculations 1 Siemens/meter = 10 mmho/cm __________________________________________________ SBE21 temperature ( sbe21Tmp) Format: dd.ddd degrees C (-5 to +35, +/- 0.01) Based on ITS90 calibration coefficients (T68 = 1.00024 * T90) __________________________________________________ SBE21 thermosalinograph ( sbe21) Format: ttttcccc T & C raw frequency values (hex) Temperature sensor s/n 3004, Calibration date = 20 June, 2000 Conductivity sensor s/n 3004, Calibration date = 20 June, 2000 Instrument installed January 2, 2003 __________________________________________________ Salinity (Salinity) Format: Salinity Salinity calculated from sea surface temperature and conductivity data values in accordance with UNESCO 44. __________________________________________________ Sea surface fluorometer ( Fluorometer) WetLabs Wet-Star fluorometer located in the clean seawater system. A MetraByte A/D converter is used to convert the 0-5 vdc fluorometer output to serial data. This device sets the output decimal point as necessary for best resolution which results in a 1 vdc fluorometer value being represented as +01000.00 in the raw MetraByte serial stream. __________________________________________________ Sound velocity ( SSV) Format: Sound_Velocity (meters/sec) Surface sound velocity calculated from sea surface temperature and conductivity data values. Intermediate salinity values are calculated in accordance with UNESCO 44. __________________________________________________ Sperry speedlog ( SPDLG) Format: Timestamp ddd.d, ss.s (speed value is in knots) (ddd.d data is unknown) __________________________________________________ True wind direction (Wnd_Dir) Format: Wnd_dir (degrees) Wind direction obtained from the IMET wind sensor and corrected for ship heading (gyro) plus ship course and speed (GPS SOG & COG). __________________________________________________ True wind speed (Wnd_Spd) Format: Wnd_spd (meters/sec) Wind speed obtained from the IMET wind sensor and corrected for ship heading (gyro) plus ship course and speed (GPS SOG & COG). __________________________________________________ True wind speed & direction (TWind) Format: Speed, Direction (meters/sec, degrees) Wind direction is given in meteorological terms; a 0 degree wind comes from the north. Ship speed and direction of travel are obtaned from GPS data (GGA SOG & COG). Sensor mounting orientation is corrected using the direction the ship is pointing obtained from the gyro (the ship is not necessarily moving in the direction its pointing). __________________________________________________ Turner fluorometer data (TF10_data) Fluorometer data from Turner Designs Model 10. Full scale = 1 volt (1000.00 from MetraByte A/D module). Exact value is not in agreement with instrument's front panel meter due to the characteristics of the calibration resistor. Science party is responsible for recording comparative readings during the cruise if needed. __________________________________________________ Turner fluorometer range (TF10_Range) Fluorometer range setting from Turner Designs Model 10 (full scale = 1 volt). Actual values reported by the MetraByte A/D module (1000.00=1 volt) are not in agreement with the value indicated in the Turner manual due to the accuracy of the calibration resistor. Actual readings are per the following table (science party should check these values at some point during the cruise): Range Expected Actual X0 0.0v 000.10 X3.16 0.4v 488.60 X10 0.7v 831.00 X31.6 1.0v 9999.99 __________________________________________________ Defined constants: WindSensorOffset = 0.0 __________________________________________________ Auxiliary information: Time stamp formats: Individual items in Athena ".dat" data files are time stamped with two different formats. The first time stamp value is in the format used by Microsoft Visual Basic: the number of days since December 31, 1899 (Dec. 31 is day 1, not day 0). Its primary purpose is to provide a continuously increasing date and time indicator for use in data graphing applications. The VB format facilitates this for some applications but converting the number to the normal human readable form can be painful. The second time stamp value (hh:mm:ss format) in combination with the file header's date information may eliminate the need for this conversion. If not, the following may be helpful: 00.00 is 00:00:00 on Dec. 30, 1899. 00.50 is 12:00:00 (noon) on the same day. 35390.58333 is 14:00:00 May 15, 1998.