The LMG data acquisition systems continuously log data from a suite of instrumentation throughout the cruise. This document describes the format of that data and its location on the distribution CDs. It also contains important information which may affect how this data is processed such as instrument failures or other known problems with acquisition.

The data collected during this cruise is distributed on a CD-ROM written in ISO9660 level-1 format. This data format has very strict requirements on filenames and organization. However, it is readable by virtually every computing platform.

The data is contained in Unix tar archives called lmgjgof1.tar, lmguw.tar, and lmgnav.tar. All of the data has been compressed using Unix "gzip" compression. Gzipped files have a ".gz" extension. Tools are available on all platforms for uncompressing and de-archiving these formats. On Macintosh, Stuffit Expander with DropStuff will open a tar archive and uncompress gzipped and Unix compressed files. For Windows9X, WinZip, a shareware utility included on this CD (remember, it is shareware) will open these files.

It is often useful to know exactly how an archive was produced when expanding its contents. Tar files were created using the following commands:

To create a list of the files in the archive:

To extract the files from the archive:

G-zipped files will have a ".gz" extension on the filename. These files can be decompressed after de-archiving, using:

The directories in the archive are structured in the following manner:

Adcp/

The ADCP data set is broken up into files representing 24 hours of data collection. The files are contained in the pingdata.zip archive and are named pingdata.xxx (xxx representing a sequential day number starting from 000). Note that these extensions do NOT represent Julian day numbers. Please refer to the file’s creation date.

Additionally, Gentoo data is contained in Gentoo.zip. The files are named ADCP2001.xxx (xxx representing the julian day number).

Some ADCP data is also transmitted to RVDAS. East and North vectors for ship’s speed relative to the reference layer and ship’s heading are archived in the navigational data section of RVDAS.

Ctd/

All CTD data acquired on the cruise can be found within this ctd directory. The data for each station consists of four files archived in the RAW folder. Each filename consists of the station number and extension: either .dat, .con, .bl, or .hdr. The type of data in each file is listed below.

The Data collected was post-processed using seasoft standard processing and is stored in the PROCESS directory.

.cnv ‘Converted’ engineering unit data file

b.cnv ‘Converted’ engineering unit data file with data averaged into pressure bins

.ros Scans marked with the bottle fire confirmation bit

.btl A summary of the data in the .ros file

.asc The data portion of the .cnv converted data file written in ascii

.hdr Header file

Within the ctd directory, the setup directory contains SeaSoft v4.242, which can be used to replay, display, or manipulate the data.

Processing Note: SEASOFT modules search the current directory for DSP, PLT, and CFG files. SEASOFT modules search the ‘input data path’ for CON, HEX, DAT, and CNV files. One exception is SEACON which searches the current directory for CON files.

JPG cruise track plots have been produced for this cruise: station1.jpg thru station5.jpg and final maps, with and without CTD points plotted. Additionally, the cruise track file (LMG01_04.trk) is also included and contains the latitude and longitude in one minute intervals.

A total of 23 MOC10 and 18 MOC1 hauls were made during this cruise. Each haul’s data is recorded in three separate and different text files and one graphics file. The format of each of these is summarized below. "M01" prefix = 1m2 MOCNESS, "M10" prefix = 10m2 MOCNESS.

Processed filename *.pro

This file contains the processed data for each tow, written in ASCII to disk in a simple configuration, which consists of:

Rows 1-5 header information about sensors and the tow

time Julian day, hours and minutes expressed as decimal

pres depth (m)

temp temperature degrees C

theta potential temperature, formulae from Fofonoff and Millard 1983

sal salinity ppt

sigma potential density, formulae from Fofonoff and Millard 1983

angle angle 0-90

flow flow counts 0000-9999

hzvel horizontal velocity (knots)

vtvel vertical velocity (m/min)

vol seawater volume filtered (m3)

net net number

fluor fluorescence (0-5 volts)

ptran extinction coefficient (0-5 volts)

oxycurrent 0-5 volts

oxytemp 0-5 volts internal to the probe

oxygen dissolved oxygen (ml/l)

lat latitude decimal degrees

lon longitude decimal degrees

Raw filename *.raw

Rows 1-5 header information about sensors and the tow

• N1 net count, counts of left response switch, 00-99
• N2 net count, counts of right response switch, 00-99
• AA net angle in degrees, 00-99
• FFFF flow counts, 0000-9999. Reset to 0000 with every net response or increment net # button command
• PPPPP pressure value, converted to decibars by the deck computer
• PTPT a decimal number derived from the temperature sensor in the pressure sensor which is used to improve the pressure calibration
• TTTTTT averaged SeaBird temperature period. The frequency from the SeaBird temperature sensor is measured and processed in the NCU to generate the value TTTTTT, a 6-digit decimal number. This number is scaled as follows:

- CCCCCC averaged SeaBird conductivity period, handled exactly like the temperature frequency and the same scaling factor should be used

• BBB battery voltage (divide value by 10)
• $GPGLL latitude and longitude in decimal degrees

Tab filename *.tab

The statistical summary for a given *.pro file. For each net, the following parameters are included:

pmin,pmax,pavg minimum,maximum and average depth of net

tmin,tmax,tavg minimum,maximum and average temperature of net

smin,smax,savg minimum,maximum and average salinity of net

amin,amax,aavg minimum,maximum and average angle of net

spmin,spmax,spavg minimum,maximum and average horizontal velocity (kt) of net

armin,armax,aravg minimum,maximum and average vertical velocity (m/sec) of net

#obs total number of observations while net was open

vol total seawater volume filtered for net

Captured screens, filenames *.jpg

PUV-GUV/

All GUV files, both binary and ASCII, have been zipped and placed in zip archives called csvfiles.zip and logfiles.zip respectively.

The GUV files were converted to CSV (Comma Separated Value) format using the Biospherical Instruments’ PUVPROF program.

The columnar format of the CSV file is listed below:

Isobars/

Analysis of mean sea level pressure from the National Center for Environmental Prediction's Medium Range Forecast Model. Updated every 12 hours.

Report/

Copies of this report in MS Word, HTML, and text formats. The weekly science reports in text format may be included upon request of the Principal Investigator.

JGOF/

rvdas/

RVDAS (Research Vessel Data Acquisition System) was developed at Lamont-Doherty Earth Observatory of Columbia University and has been used on the R/V Maurice Ewing for several years. It was adapted for use on the Nathaniel B. Palmer and her sister ship, the R/V Laurence M. Gould.

Below you will find detailed information on the data included. Be sure to read the "Significant Acquisition Events" section below for important information about data acquisition during this cruise.

Data File Names and Structures

RVDAS data is divided into two broad categories, Underway and Navigation. The groups are abbreviated "uw" and "nav". Thus, these two tar files, lmguw.tar and lmgnav.tar exist under the top-level rvdas directory. The instruments are broken down as shown. Each data file is g-zipped to save space on the distribution. Not all data types are collected everyday or on every cruise.

RVDAS data files are named following the convention: LMG[FileID].dDDD.

• The FileID is a 4-character code representing the system being logged, for example: lmet (for meteorology)
• DDD is the Julian day of the data collection

Data is received by the RVDAS system via RS-232 serial connections. The data files that comprise the rvdas data set are described below. A time tag is added to each line of data received and the data is written to disk.

Where, YY: two-digit year, DDD: Julian Day, HH: 2 digit hours, MM: 2 digit minutes SS.SSS: seconds. All times are UTC.

The delimiters used to separate fields in the raw data files are usually spaces and commas, but other delimiters are used (::, =, @) and occasionally there is no delimiter. Care should be taken when reprocessing the data that the fields separations are clearly understood. An example data

99+099:00:18:19.775 hf,305.2,lf,304.3

00+040:00:00:00.928 16-10-97 00:01:19 005.53 005.53 005.69 145 141 005.15 005.12 005.15

146 148 004.4 004.4 004.4 94.07 94.06 94.07 0981.40 -0.023 00.292 00.315

00+348:01:59:52.128 1539.40

00+040:00:00:06.153 6926 15.8827 0.2010 2.9218 3.239 4.334e-01

00+019:23:59:59.099 $PUHAW,UVH,-1.48,-0.51,250.6