NBP0701
Data Report

 

 

 

 

 

 

 

 

 

 

 

Prepared by:

Jennifer Ayers,

Raytheon Polar Services Company

US Antarctic Program

22 December 2006 - 29 January 2007



Table of Contents

 

1     Introduction..................................................................................................................... 1

1.1      Archive Commands................................................................................................... 1

1.2      Distribution Contents at a Glance.......................................................................... 2

1.3      Obtaining Data from the MGDS............................................................................... 2

1.4      Research Overview.................................................................................................. 3

2     Distribution Contents................................................................................................... 5

2.1      Cruise Information.................................................................................................. 5

2.1.1      Cruise Track................................................................................................................. 5

2.1.2      Satellite Images............................................................................................................. 5

2.1.3      Science Reports............................................................................................................. 5

2.2      Seismic Data............................................................................................................ 5

2.3      NBP Processed Data Products................................................................................. 1

2.3.1      JGOFS......................................................................................................................... 1

2.3.2      MGD77........................................................................................................................ 1

2.4      Science of Opportunity............................................................................................. 3

2.4.1      ADCP.......................................................................................................................... 3

2.4.2      pCO2.......................................................................................................................... 3

2.5      Ocean Science.......................................................................................................... 3

2.5.1      XBT............................................................................................................................ 3

2.5.2      CTD............................................................................................................................ 4

2.6      RVDAS..................................................................................................................... 4

2.6.1      Sensors and Instruments................................................................................................. 4

Underway Sensors................................................................................................................................................................................ 4

Meteorology and Radiometry...................................................................................................................................................... 4

Geophysics........................................................................................................................................................................................ 5

Oceanography................................................................................................................................................................................... 5

Navigational Instruments.................................................................................................................................................................. 5

2.6.2      Raw Data..................................................................................................................... 5

Underway Data....................................................................................................................................................................................... 6

Sound Velocity Probe (svp1)....................................................................................................................................................... 6

Meteorology (met1)........................................................................................................................................................................ 6

Gravimeter (grv1)............................................................................................................................................................................ 7

Bathy 2000 (bat1)........................................................................................................................................................................... 8

Knudsen (knud)............................................................................................................................................................................... 9

Simrad EM120 (mbdp)................................................................................................................................................................... 9

Simrad EK500 (sim1)................................................................................................................................................................... 10

Thermosalinograph (tsg1).......................................................................................................................................................... 10

Fluorometer (flr1)......................................................................................................................................................................... 10

pCO2................................................................................................................................................................................................. 10

Navigational Data.............................................................................................................................................................................. 11

Seapath GPS (seap)....................................................................................................................................................................... 11

Trimble (P-Code) GPS (PCOD).................................................................................................................................................. 13

Gyro Compass (gyr1)................................................................................................................................................................... 14

ADCP Course (adcp)..................................................................................................................................................................... 14

Sound Velocity Probe (svp1).................................................................................................................................................... 15

2.6.3      Processed Data............................................................................................................ 15

pCO2-merged...................................................................................................................................................................................... 15

tsgfl........................................................................................................................................................................................................ 15

3     Calculations................................................................................................................... 16

3.1      TSG........................................................................................................................ 16

3.2      PAR........................................................................................................................ 17

3.3      PIR......................................................................................................................... 17

3.4      PSP........................................................................................................................ 17

4     Acquisition Problems and Events............................................................................ 18

5     Appendix:  Sensors and Calibrations....................................................................... 19

5.1      Shipboard Sensors.................................................................................................. 19

5.2      Calibrations.......................................................................................................... 19

Anemometer (Port)............................................................................................................................................................................. 20

Anemometer (Starboard).................................................................................................................................................................. 21

Anemometer (Starboard) – Replacement..................................................................................................................................... 22

Barometer............................................................................................................................................................................................. 23

Humidity / Wet Temp........................................................................................................................................................................ 24

PIR.......................................................................................................................................................................................................... 25

PSP......................................................................................................................................................................................................... 26

PAR........................................................................................................................................................................................................ 27

GUV........................................................................................................................................................................................................ 28

Underway Conductivity................................................................................................................................................................... 29

Underway Temperature Sensor....................................................................................................................................................... 30

Underway Remote Temperature Sensor........................................................................................................................................ 31

Underway Transmissometer............................................................................................................................................................ 32

Gravity Tie Start (New Zealand)..................................................................................................................................................... 33

Gravity Tie End (McMurdo............................................................................................................................................................. 34

5.3      Seismic Data Details.............................................................................................. 35

 

 


1       Introduction

The NBP research vessel data acquisition systems (RVDAS) continuously log data from the instruments used during the cruise.  This document describes:

 

·       The structure and organization of the data on the distribution media

·       The format and contents of the data strings

·       Formulas for calculating values

·       Information about the specific instruments in use during the cruise

·       A log of acquisition problems and events during the cruise that may affect the data

·       Scanned calibration sheets for the instruments in use during the cruise

The data is distributed on a DVD-R written in ISO9660 level-1 format.  It is readable by virtually every computing platform.   All data has been packaged in Unix tar archive files. Most files inside the tar archive have been compressed to reduce size. Compressed files are identified by the extension “gz”. Tools are available on all platforms for uncompressing and de-archiving these files:

 

·       On Macintosh, use Stuffit Expander with DropStuff or the command line utilities. 

·       On Windows, use WinZip or the freeware program 7zip (installer is located in /other/7zip.exe).

·       tar, gzip, and gunzip are standard tools on all Unix and Unix-like systems.

·       Multibeam data is distributed separately.

IMPORTANT:  Read the last section, “Acquisition Problems and Events,” for important information that may affect the processing of this data.

1.1      Archive Commands

All archives were created using the command:

tar [z]cvf archive_name files_to_archive     

with [z] being used to create “.tgz” archives.

 

To create a list of the files in the archive, use the Unix command:

tar [z]tvf  archive_name  > contents.list

where contents.list is the name of the file to create

 

To extract the files from the archive:

tar [z]xvf  archive_name file(s)_to_extract

 


1.2      Distribution Contents at a Glance

 

NBP0701 RVDAS Data

 

 

NBP0701.be.gmt

NBP0701.gmt

NBP0701.mgd

NBP0701.ps

NBP0701.trk

NBP0701.doc

NBP0701.pdf

NBP0701_watch.xls

 

 

imagery/             

0701Imag.tar

 

 

 

ocean/   

0701xbt.tar

 

process/

0701JGOF.tar

0701MGD.tar

0701PCO2.tar

0701PROC.tar

0701QC.tar

 

rvdas/nav/

0701adcp.tar  

0701gp02.tar

0701gyr1.tar

0701PCOD.tar

0701seap.tar

0701sp1b.tar

0701sp2a.tar

0701trax.tar

 

rvdas/uw/

0701bat1.tar

0701bird.tar

0701eng1.tar

0701flr1.tar

0701grv1.tar

0701mag1.tar

0701mbdp.tar

0701met1.tar

0701oyo1.tar

0701pco2.tar

0701pguv.tar

0701sssg.tar

0701svp1.tar

0701syn1.tar

0701tsg1.tar

 

 

1.3      Obtaining Data from the MGDS

The complete data set is distributed on DVDs and tapes at the end of the cruise; additionally, a complete copy will be sent to the Antarctic Multibeam Synthesis at the MGDS (http://www.marine-geo.org/). You can locate the all information for and download data from this cruise at the web site by selecting your cruise name from the data link tool. You can also download and use the java application GeoMapApp to interactively access multibeam and other data sets. Data sent to the database will not be downloadable until the proprietary hold has been released. You can contact the MGDS at:

 

MGDS Data Manager

Lamont-Doherty Earth Observatory

61 Route 9W

Palisades NY 10964 USA

845-818-3745 Phone/Fax

info@marine-geo.org

 

1.4      Research Overview

Collaborative Research: The Connection Between mid-Cenozoic Seafloor Spreading and the Western Ross Sea Embayment

Principle Investigators: Dr. Steve Cande, Dr. Joann Stock

 

Cruise NBP0701 conducted a marine geophysical survey to study the structural relationship between the Adare Basin, east of Cape Adare, and the Northern and Central basins of the Ross Embayment.  Previous cruises on the Palmer have documented that there was 170 km of seafloor spreading between East and West Antarctica from 40 to 26 Ma (in the mid−Cenozoic). This episode of seafloor spreading produced new seafloor in the Adare Basin, but the relationship of this seafloor spreading episode to the continental basins of the Ross Embayment, to the south, has not been established.

 

NBP0701 acquired magnetic, gravity, swath bathymetry, and seismic data from the southern end of the Adare Basin south into the Northern Basin and Central Basin of the Ross Embayment in order to test between two hypotheses:

 

1)     There is complete structural continuity southward from the Adare Basin into the Northern Basin, and that the Northern Basin of the Ross Sea also experienced 170 km of extension; or

2)     Some displacement was transferred sideways into the Central Basin of the Ross Embayment.

 

The results have important implications for the overall geological history of Antarctica during the mid−Cenozoic, and also for processes that control the transition from continental to oceanic rifting, which is a topic of interest to many scientists worldwide.

 

Collaborative Research: Constraining the Petrogenesis and Mantle Source of Adare Basin Seamount Lavas

Principle Investigators: Dr. Paterno Castillo, Dr. Kurt Panter

 

The fundamental cause of Cenozoic magmatism in west Antarctica has been explained by a variety of models based primarily on geochemical evidence gathered from igneous rocks collected from continental west Antarctica and from Ross Island. The primary objective of this project is to analyze critical age, petrographic, petrochemical, and isotopic data that can be used to assess these existing but often conflicting models on mantle geodynamics and control on magmatism in the region.

 

To accomplish this goal, NBP0701 collected samples by dredging from the numerous

but relatively small volcanic seamounts in the Adare Basin in western Ross Sea, Northern Victoria Land, which we collectively called Adare Basin Seamounts (ABS). By establishing that these seamounts are of Cenozoic age and genetically related to other Cenozoic igneous rocks in west Antarctica, we should be able to constraint better the "pristine" mantle source composition of west Antarctic magmas by virtue of their small-volume, oceanic form of intraplate magmatism.

 

Our investigation for the first time provides geochronologic and geochemical data for submarine intraplate magmatism in the Adare Basin and can potentially be pivotal in the study of magmatism not only in the west Antarctic, but also in the entire SW Pacific region.

 

Hydroacoustic Study to Calibrate Nuclear Test Monitoring Systems

Mr. Scott Jenkins and Dr. Donna Blackman

 

The hydroacoustic study provided information to calibrate a component of the United Nations International Monitoring System (IMS) for nuclear test monitoring. Small explosive charges (4-lb SUS charges) designed to fire at water depths of 200-600 m were deployed at stations spaced approximately 200 nm apart along the transit. These very brief impulsive signals propagated to distant hydrophone receivers. Documentation of differences between predicted (based on IMS hydroacoustic modeling approaches) and measured arrival time and frequency content of the recorded signal will be used to quantify the uncertainty introduced by high temperature/salinity gradients that characterize the Antarctic Convergence Zone (ACZ). The zone's oceanographic conditions alter the path of sound propagation and can cause frequency-dependent loss of signal energy due to scattering. Although our signals were quite small, particularly relative to a clandestine nuclear test in the oceans, the travel-time and loss frequencies that we document can be extended to address relevant test scenarios. Obtaining information from across the ACZ has been a US Dept. of Energy priority for the past three years.

 

2       Distribution Contents

2.1      Cruise Information

2.1.1     Cruise Track

The distribution DVD includes a GMT cruise track file (NBP0701.trk).  It contains the longitude and latitude at one-minute intervals extracted from the NBP0701.gmt file.

A plot of the cruise track is available in postscript, pdf, and jpeg formats, in the files: NBP0701.track.jpg, NBP0701.track.pdf, and 0701trk.ps.  These images are located in the trkmaps.tar file.

2.1.2     Satellite Images

Satellite, weather, and isobar images processed during this cruise can be found in the directory /images in three tar files: ice.tar, isobar.tar, and wx.tar (weather).

2.1.3     Science Reports

Weekly cruise science reports are located in the directory /scirep.

2.2      Seismic Data

Seismic data has been distributed on sets of 22 DVDs.  Appendix 5.3 describes the particulars of the seismic data collected.

 

The diagram below illustrates the seismic instrument configuration used on NBP0701.



2.3      NBP Processed Data Products

Two primary datasets are created on each cruise: JGOFS and MGD77.

The data processing scripts used to produce JGOFS and MGD77 data sets create a number of intermediate files.  These files are included on the data distribution media in a file called 0701proc. They are included to make re-processing easier in the event of an error, but no extensive detail of the formats is included in this document. For information, please contact itvessel@usap.gov.

2.3.1     JGOFS

The JGOFS data set may be found on the distribution media in the file /process/0701JGOF.tar.  The archive contains one file produced for each day named jgDDD.dat.gz, where DDD is the year-day the data was acquired. The “.gz” extension indicates that the individual files are compressed before archiving. Each daily file consists of 22 columnar fields in text format as described in the table below. The JGOFS data set is created from calibrated data decimated at one-minute intervals. Several fields are derived measurements from more than a single raw input.  For example, Course Made Good (CMG) and Speed Over Ground (SOG) are calculated from gyro and GPS inputs. Daily plots during the cruise are produced from the JGOFS data set. Note:  Null, unused, or unknown fields are indicated as “NAN” or 9999 in the JGOFS data.

Field

Data

Units

01

UMT date

dd/mm/yy

02

UMT time

hh:mm:ss

03

NGL latitude (negative is South)

tt.tttt

04

NGL longitude (negative is West)

ggg.gggg

05

Speed over ground

Knots

06

GPS HDOP

-

07

Gyro Heading

Degrees (azimuth)

08

Course made good

Degrees (azimuth)

09

Mast PAR

mEinsteins/meter2 sec

10

Sea surface temperature

°C

11

Sea surface conductivity

siemens/meter

12

Sea surface salinity

PSU

13

Sea depth (uncorrected, calc. sw sound vel. 1500 m/s)

meters

14

True wind speed (max speed windbird)

meters/sec

15

True wind direction (max speed windbird)

degrees (azimuth)

16

Ambient air temperature

°C

17

Relative humidity

%

18

Barometric pressure

mBars

19

Sea surface fluorometry

volts (0-5 FSO)

20

Not used

-

21

PSP

W/m2

22

PIR

W/m2

2.3.2     MGD77

The MGD77 data set is contained in a single file for the entire cruise.  It can be found in the top level of the distribution data structure as NBP0701.mgd.  The file NBP0701.gmt is created from the MGD77 dataset using the “mgd77togmt” utility.  NBP0701.gmt can be used with the GMT plotting package. 

 

The data used to produce the NBP0701.mgd file can be found at the root of the distribution media and in the file /process/0701proc.tar.  The data files in the archive contain a day’s data and follow the naming convention Dddd.fnl.gz, where ddd is the year-day. These files follow a space-delimited columnar format that may be more accessible for some purposes. They contain data at one-second intervals rather than one minute and are individually “gzipped” to save space. Below is a detailed description of the MGD77 data set format. 

 

All decimal points are implied. Leading zeros and blanks are equivalent.  Unknown or unused fields are filled with 9s.  All “corrections”, such as time zone, diurnal magnetics, and EOTVOS, are understood to be added.

Col

Len

Type

Contents

Description, Possible Values, Notes

1

1

int

Data record type

Set to “5” for data record

2-9

8

char

Survey identifier

 

10-12

3

int

Time zone correction

Corrects time (in characters 13-27) to UMT when added; 0 = UMT

13-16

4

int

Year 

4 digit year

17-18

2

int

Month 

2 digit month

19-20

2

int

Day

2 digit day

21-22

2

int

Hour

2 digit hour

23-27

5

real

Minutes x 1000

 

28-35

8

real

Latitude x 100000

+ = North

- = South. (–9000000 to 9000000)

36-44

9

real

Longitude x 100000

+ = East

- = West.  (–18000000 to 18000000)

45

1

int

Position type code

1=Observed fix

3=Interpolated

9=Unspecified

46-51

6

real

Bathymetry, 2- way travel time

In 10,000th of seconds.  Corrected for transducer depth and other such corrections

52-57

6

real

Bathymetry, corrected depth

In tenths of meters.

58-59

2

int

Bathymetric correction code

This code details the procedure used for determining the sound velocity correction to depth

60

1

int

Bathymetric type code

1 = Observed

3 = Interpolated (Header Seq. 12)

9 = Unspecified

61-66

6

real

Magnetics total field, 1ST sensor

In tenths of nanoteslas (gammas)

67-72

6

real

Magnetics total field, 2ND sensor

In tenths of nanoteslas (gammas), for trailing sensor

73-78

6

real

Magnetics residual field

In tenths of nanoteslas (gammas).  The reference field used is in Header Seq. 13

79

1

int

Sensor for residual field

 

1 = 1st or leading sensor

2 = 2nd or trailing sensor

9 = Unspecified

80-84

5

real

Magnetics diurnal correction

In tenths of nanoteslas (gammas).  (In nanoteslas) if 9-filled (i.e., set to “+9999”), total and residual fields are assumed to be uncorrected; if used, total and residuals are assumed to have been already corrected.

85-90

6

F6.0

Depth or altitude of magnetics sensor

(In meters) 

+ = Below sea level 

3 = Above sea level

91-97

7

real

Observed gravity

In 10th of mgals.  Corrected for Eotvos, drift, tares

98-103

6

real

EOTVOS  correction

In 10th of mgals.

E = 7.5 V cos phi sin alpha + 0.0042 V*V

104-108

5

real

Free-air anomaly

In 10th of mgals

G = observed

G = theoretical

109-113

5

char

Seismic line number

Cross-reference for seismic data

114-119

6

char

Seismic shot-point number

 

120

1

int

Quality code for navigation

5=Suspected, by the originating institution

6=Suspected, by the data center

9=No identifiable problem found

2.4      Science of Opportunity

2.4.1     ADCP

The ADCP system measures currents in a depth range up to 1200 m (OS38 in deep profiling mode). In bad weather, ice, or unfavorable sea state the range is reduced, and sometimes no valid measurements are made.  ADCP data collection is the OPP-funded project of Eric Firing (University of Hawaii) and Teri Chereskin (Scripps Institution of Oceanography).  Data is collected on both the LMG and the NBP for the benefit of scientists on each cruise, and for the long-term goal of building a profile of current structure in the Southern Ocean.

 

Matlab “.mat” files containing current contour and vector data have been placed in the file /adcp/0701MAT.tar. Please note that these files must be considered preliminary only. Data are not a “final product” until post-processing has been performed by the principal investigators. For more information on data format, post-processing, and for data download, please visit: http://currents.soest.hawaii.edu.

 

 A data feed is sent from the ADCP system to RVDAS whenever a reference layer is acquired. This feed contains east and north vectors for ship’s speed, relative to the reference layer, and ship’s heading. This data is saved in files located in 0701adcp.tar in the directory /rvdas/nav.

2.4.2     pCO2

The NBP carries a pCO2 measurement system from Lamont-Doherty Earth Observatory (LDEO). pCO2 data is recorded by RVDAS and transmitted to LDEO at the end of each cruise. pCO2 data is archived in the file 0701pco2.tar in the /process directory, which contains the pCO2 instrument’s data merged with GPS, meteorological and other oceanographic measurements.  For more information contact Colm Sweeney (csweeney@ldeo.columbia.edu).

2.5      Ocean Science

2.5.1     XBT

During the cruise, eXpendable BathyThermographs were used to obtain water column temperature profiles. XBT profiles allow corrections to the sound velocity profile for the multi-beam system.  The data files from these launches are included as 0701xbt.tar in the /ocean directory.

2.5.2     CTD

During the cruise, CTDs were used to obtain water column Conductivity, Temperature and Depth profiles.  The data files from these launches are included as 0606ctd.tar in the /ocean directory.

 

2.6      RVDAS

The Research Vessel Data Acquisition System (RVDAS) was developed at Lamont-Doherty Earth Observatory of Columbia University and has been in use on its research ship for many years.  It has been extensively adapted for use on the USAP research vessels.

 

Daily data processing of the RVDAS data is performed to calibrate and convert values into useable units and as a check of the proper operation of the DAS. Both raw and processed data sets from RVDAS are included in this data distribution. Quality-control plots for most instruments are created daily, and may be found in postscript format in the file /process/0701QC.tar. The tables below provide detailed information on the sensors and data. Be sure to read the “Significant Acquisition Events” section for important information about data acquisition during this cruise.

2.6.1     Sensors and Instruments

RVDAS data is divided into two general categories, underway and navigation.  Raw data will be found on the distribution media as subdirectories under the top level rvdas directory:  /rvdas/uw, and /rvdas/nav. Each instrument or sensor produces a data file named with its channel ID.  Each data file is g-zipped to save space on the distribution media.  Not all data types are collected every day or on every cruise.

The naming convention for data files produced by the sensors and instruments is: NBP[CruiseID][ChannelID].dDDD.  Example: NBP0701met1.d365.

 

·       The CruiseID is the numeric name of the cruise, in this case, NBP0701.

·       The ChannelID is a 4-character code representing the system being logged.  For example the meteorology designation is “met1”.

·       DDD is the day of year the data was collected.

Underway Sensors

Meteorology and Radiometry

Measurement

Channel ID

Collect. Status

Rate

Instrument

Air Temperature

met1

Continuous

1 sec

R. M. Young 41372LC

Relative Humidity

met1

Continuous

1 sec

Wind Speed/Direction

met1

Continuous

1 sec

R.M. Young 5106

Barometer

met1

Continuous

1 sec

R.M. Young 61201

PIR (LW radiation)

met1

Continuous

1 sec

Eppley PIR

PSP (SW radiation)

met1

Continuous

1 sec

Eppley PSP

PAR

met1

Continuous

1 sec

BSI QSR-240

GUV

guv

Continuous

2 sec

BSI PUV-2511

PUV

puv

Continuous

 

BSI PUG-2500

Geophysics

Measurement

Channel ID

Collect. Status

Rate

Instrument

Gravimeter

grv1

Continuous

10 sec*

LaCoste & Romberg

Magnetometer

mag1

Not collected

15 sec

EG&G G-866

Bathymetry

bat1

Per direction

Varies

ODEC Bathy 2000

Bathymetry

knu1

Per direction

Varies

Knudsen 320B/R

Bathymetry

sim1

Not collected

Varies

Simrad EK500 Sonar

*Data is output every second but only changes every 10 seconds.

Oceanography

Measurement

Channel ID

Collect. Status

Rate

Instrument

Conductivity

tsg1

Continuous

6 sec

SeaBird SBE-21

Salinity

tsgfl

Continuous

6 sec

Calc. from pri. temp

Sea Surface Temp

tsg1

Continuous

6 sec

SeaBird 3-01/S

Fluorometry

flr1

Continuous

1 sec

Turner 10-AU-005

Fluorometry

flr1 & tsg1

Continuous

6 sec

Transmissometry

tsg1

Continuous

6 sec

WET Lab C-Star

pCO2

pco2

Continuous

70 sec

(LDEO)

ADCP

adcp

Continuous

varies

RD Instruments

 

Navigational Instruments

Measurement

Channel ID

Collect. Status

Rate

Instrument

Trimble GPS

PCOD

Continuous

1 sec

Trimble 20636-00SM

Gyro

gyr1

Continuous

0.2 sec

Yokogawa Gyro

SeaPath

seap

Continuous

1 sec

SeaPath 200

 

2.6.2     Raw Data

Data is received from the instrument system via RS-232 serial connections. A time tag is added by RVDAS at the beginning of each line of data in the form,

yy+dd:hh:mm:ss.sss [data stream from instrument]

where

yy = two-digit year
ddd = day of year
hh =  2 digit hour of the day
mm =  2 digit minute
ss.sss =  seconds

 

All times are reported in UTC.  The delimiters that separate fields in the raw data files are often spaces and commas but can be other characters such as :  =  @.  Occasionally no delimiter is present.  Care should be taken when reprocessing the data that the field’s separations are clearly understood. 

 

In the sections below a sample data string is shown, followed by a table that lists the data contained in the string. 

Underway Data

Sound Velocity Probe (svp1)

00+348:01:59:52.128  1539.40

Field

Data

Units

1

RVDAS Time tag

 

2

Sound velocity in ADCP sonar well

m/s

Meteorology (met1)

01+322:00:03:27.306 04.5 292 010 05.7 294 010 0959.6 000.2 093.1

-000.1537 0001.0886 0012.8248

Field

Data

Units

1

RVDAS time tag

 

2

Port anemometer speed (relative)

m/s

3

Port anemometer direction (relative)

deg

4

Port anemometer standard deviation

deg

5

Starboard anemometer speed (relative)

m/s

6

Starboard anemometer direction (relative)

deg

7

Starboard anemometer standard deviation

deg

8

Barometer

mBar

9

Air temperature

°C

10

Relative humidity

%

11

PSP (short wave radiation)*

mV

12

PIR (long wave radiation)*

mV

13

PAR (photo synthetically available radiation)*

mV

*See page 20 for calculations.


Gravimeter (grv1)

There are two sets of fields output by the gravity meter. The data record is output once per second, and identified by “$DAT” in the id field. A summary of sensor environmental data is output every ten seconds, identified by “%ENV” in the id field.

 

Data record ($DAT):

05+194:00:00:27.995 $DAT,2005/ 7/13, 0: 7: 7.36,194, 9050.37, 9050.06,    5410.86,   -0.00,   -0.01,   -0.02,    0.00,    0.00,    0.70,    0.19,   -0.12,   -0.25,    0.00, -69.45711315, -54.32181487,  0.000, 285.200,

Field

Data

Conversion

Units

1

RVDAS time tag

 

 

2

Text string (id field)

$DAT for data record

 

3

Date

YYYY/MM/DD

 

4

Time

HH:MM:SS.SS

 

5

Day of Year

DDD

 

6

Gravity count

mgal = count x 1.0046 + offset

count

7

Spring Tension

 

CU

8

Beam Position

Volts x 750,000

 

9

VCC

 

 

10

AL

 

 

11

AX

 

 

12

VE

 

 

13

AX2

 

 

14

XACC2

 

 

15

LACC2

 

 

16

CROSS ACCEL

 

GAL

17

LONG ACCEL

 

GAL

18

EOTVOS CORR

 

MGAL

19

LONGITUDE

 

Degrees

20

LATITUDE

 

Degrees

21

HEADING

 

Degrees

22

VELOCITY

 

Knots

 

Environmental record ($ENV)

05+183:19:13:10.945 %ENV,2005/ 7/ 2,19:19:52.16,183,S-036/V1.5,    3.34,   47.19,   20.34,1.111840E-1,-0.57700,-0.10591, 0.40180, 2.55260, 0.43000,   1, 300

Field

Data

Conversion

Units

1

RVDAS time tag

 

 

2

Text string (id field)

$ENV for environmental record

 

3

Date

YYYY/MM/DD

 

4

Time

HH:MM:SS.SS

 

5

Day of Year

DDD

 

6

Meter ID

 

 

7

Meter Pressure

 

inch-Hg

8

Meter temp

 

°C

9

Ambient temp

 

°C

10

K-Factor

 

 

11

VCC Coeff

 

 

12

AL Coeff

 

 

13

AX Coeff

 

 

14

VE Coeff

 

 

15

AX2 Coeff

 

 

16