Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005

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Frequently-anticipated questions:


What does this data set describe?

Title:
Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005
Abstract:
Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine the importance of nutrient delivery to Chesapeake Bay via this pathway. Resource managers are concerned about nutrients that are entering the estuary via submarine groundwater discharge from this primarily agricultural watershed that may be contributing to eutrophication, harmful algal blooms, and fish kills. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the estuary in April and May 2007. Techniques used included continuous resistivity profiling (CRP), piezometer sampling, seepage meter measurements, and collection of a radon tracer time series. Better understanding of the style, locations, and rates of groundwater discharge could lead to improved models and mitigation strategies for estuarine nutrient over-enrichment in the Corsica River Estuary, and other similar settings.
  1. How should this data set be cited?

    Bratton, John F. , and Cross, VeeAnn A. , 2011, Raw and Modified Raw Continuous Resistivity Profile Data Collected in the Corsica River Estuary, Maryland on May 17, 2007 on USGS Cruise 07005: Open-File Report 2010-1094, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Cross, VeeAnn A. , Bratton, John F. , Worley, Charles R. , Crusius, John, and Kroeger, Kevin D. , 2011, Continuous resistivity profiling data from the Corsica River Estuary, Maryland: Open-File Report 2010-1094, U.S. Geological Survey, Coastal and Marine Geology Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -76.149917
    East_Bounding_Coordinate: -76.108067
    North_Bounding_Coordinate: 39.086267
    South_Bounding_Coordinate: 39.074783

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 17-May-2007
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Degrees and decimal minutes.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Local surface
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    John F. Bratton
    U.S. Geological Survey
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2254 (voice)
    (508) 457-2310 (FAX)
    jbratton@usgs.gov

    Contact_Instructions:
    Current address: NOAA/GLERL 4840 S. State Rd. Ann Arbor MI 48108-9719 734-741-2235 John.Bratton@noaa.gov


Why was the data set created?

The purpose of this dataset is to provide the raw resistivity data collected on May 17, 2007 in the Corsica River Estuary by the AGI SuperSting system. Modifications to the raw data were necessary in order to prepare the data for processing.


How was the data set created?

  1. From what previous works were the data drawn?

    (source 1 of 1)
    Source_Contribution:
    The continuous resistivity profile (CRP) system used on this cruise was an AGI SuperSting marine system described at the website: www.agiusa.com/marinesystem.shtml. The particular system used for this acquisition was a 50-m streamer with an 11 electrode array with electrodes spaced 5 meters apart. The source electrodes are graphite, while the receiver electrodes are stainless steel. A dipole-dipole configuration was used for the data collection in which two fixed current electrodes are assigned with the measurement of voltage potential between electrode pairs in the remaining electrodes. The maximum depth below the water surface the streamer can reach is approximately the streamer length. So for the 50-m streamer, maximum depth is about 12.5 meters. Each line of data acquisition records several files. The two files necessary for processing are the *.stg and the *.gps file. The STG file contains the resistivity data, while the GPS file contains the navigation information. The navigation system used in concert with the CRP system is a Lowrance LMS-480M with an LGC-2000 GPS antenna and a 200 kHz fathometer transducer. The transducer also contains a temperature sensor. Lowrance indicates the speed of sound used by the system is 4800 feet/second. Both the temperature and depth information are recorded in the logged GPS file. There are instances where no depth or temperature information is recorded due to an equipment problem. The CRP system images the subsurface electrical properties of an estuarine, riverine or lacustrine environment. Resistivity differences can be attributed to subsurface geology (conductive vs less conductive layers) and hydrogeologic conditions with fresh water exhibiting high resistivity and saline conditions showing low resistivity.

  2. How were the data generated, processed, and modified?

    Date: 2007 (process 1 of 5)
    The data were transferred from the logging computer via AGISSAdmin software version 1.3.2.165. The data files available for this day are L37F1*, L38F1*, L39F1*, L39F2*, L40F1*, L41F1*, L42F1*, L43F1*, L44F1*, L45F1*, L46F1*, L47F1*, L48F1*, L49F1*, L49F2*, L50F1*, L51F1*, L52F1*, L53F1*, L54F1*, L54F2*, L55F1*, L55F2*, L56F1*, L57F1*, L58F1*, l58F2*, L59F1*, L60F1*, L61F1*, L62F1*, L63F1*, L64F1*, L65F1*, L66F1*, L67F1*, L68F1*, L69F1*, L70F1*, L71F1*, L72F1*, L73F1*, L74F1*, L75F1*. These files were then transferred via a thumb drive to the processing computer. The files included in this publication are the *.crs, *.cmd, *.gps, and *.stg. The two files essential for processing are the GPS and STG files. The GPS file contains the navigation, and in the case of the Lowrance system also includes water depth and temperature. The STG file contains the resistivity measurements from each of the electrodes. The CRS file contains the contact resistance readings. The CMD file contains the parameters for data collection. These last two files aren't necessary for data processing, but can be useful in terms of troubleshooting. This process step and all subsequent process steps were performed by the same person - VeeAnn A. Cross.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Date: 2007 (process 2 of 5)
    The first step is to check the navigation recorded in the *.gps file for each line of acquisition. At first glance, the navigation data in the files seem fine so I ran an AWK script which extracts the navigation, bathymetry, and temperature information recorded in each individual GPS data file. (I refers to the line name, which for this day are L37F1, L38F1, L39F1, L39F2, L40F1, L41F1, L42F1, L43F1, L44F1, L45F1, L46F1, L47F1, L48F1, L49F1, L49F2, L50F1, L51F1, L52F1, L53F1, L54F1, L54F2, L55F1, L55F2, L56F1, L57F1, L58F1, l58F2, L59F1, L60F1, L61F1, L62F1, L63F1, L64F1, L65F1, L66F1, L67F1, L68F1, L69F1, L70F1, L71F1, L72F1, L73F1, L74F1, L75F1. The awk script from May 16th that was able to handle all problems was used on this day's data.
    AWK script "awkhold":
    BEGIN {
    FS = ","
    }
    {
    FS = ","
    ARGC = 2
    depth = -9999
    temp = -9999
    if ($1=="$GPRMC")
    	{
    	utctime = $2
    	latdeg = substr($4,1,2)
    	latmin = substr($4,3,6)
    	declat = latdeg + (latmin/60)
    	londeg = substr($6,1,3)
    	lonmin = substr($6,4,6)
    	declon = -1 * (londeg + (lonmin/60))
    	if (NR==1) {
    		holddepth = -9999
    		holdtemp = -9999
    		}
    	else {
    		printf("%s, %9.6f, %9.6f, %5.1f, %5.1f, %s\n", holdutctime, >holddeclon, holddeclat, holddepth, holdtemp, ARGV[2])
    	}
    	holdutctime = utctime
    	holddeclon = declon
    	holddeclat = declat
    	holddepth = -9999
    	holdtemp = -9999
    	}
    if ($1=="$SDDPT")
    	{
    	depthreal = $2
    	holddepth = depthreal
    	}
    if ($1=="$SDMTW")
    	{
    	tempreal = $2
    	holdtemp = tempreal
    	}
    }
    END {
    printf("%s, %9.6f, %9.6f, %5.1f, %5.1f, %s\n", holdutctime, holddeclon, holddeclat, holddepth, holdtemp, ARGV[2])
    }
    
    This AWK script was initialized by "dohold" - shell script run under CYGWIN (UNIX like environment that runs under Windows):
    files=`ls *.gps | cut -d. -f1 | tr "[A-Z"] ["a-z"]`
    for file in $files
    do
    	awk -f awkhold $file.gps $file > $file.holds
    done
    

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Data sources used in this process:
    • *.gps

    Data sources produced in this process:

    • *.holds

    Date: 2007 (process 3 of 5)
    These files were then appended to each other using the UNIX cat command. cat l37f1.holds l38f1.holds l39f1.holds l39f2.holds l40f1.holds l41f1.holds l42f1.holds l43f1.holds l44f1.holds l45f1.holds l46f1.holds l47f1.holds l48f1.holds l49f1.holds l49f2.holds l50f1.holds l51f1.holds l52f1.holds l53f1.holds l54f1.holds l54f2.holds l55f1.holds l55f2.holds l56f1.holds l57f1.holds l58f1.holds l58f2.holds l59f1.holds l60f1.holds l61f1.holds l62f1.holds l63f1.holds l64f1.holds l65f1.holds l66f1.holds l67f1.holds l68f1.holds l69f1.holds l70f1.holds l71f1.holds l72f1.holds l73f1.holds l74f1.holds l75f1.holds > day3holds.txt

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Data sources used in this process:
    • *.holds

    Data sources produced in this process:

    • day3holds.txt

    Date: 2007 (process 4 of 5)
    VI under CYGWIN was used to add the appropriate header line and the comma-delimited text file was imported to ArcMap 9.2: Tools - Add XY Data. The X field is longitude; Y field is latitude, and the Coordinate System was defined as Geographic, NAD83. Visual inspection indicates that the navigation from this day of data collection is fine.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Data sources used in this process:
    • day3holds.txt

    Date: 2007 (process 5 of 5)
    After the initial processing, it became apparent that I needed to split L67F1 because of a gap in the navigation. This means that the GPS file and the STG file need to be split resulting in L67F1_part1.gps and L67F1_part2.gps as well as L67F1_part1.stg and L67F1_part2.stg. Although the anomaly is found after some processing, the edit is made to the raw data - hence the reason for recording this information with the raw data. This dataset includes both the original (unsplit) and modified files needed for further processing. In addition, L44f1 had an anomaly at the end of the file. Removing the last grouping of 8 electrode readings solved this problem. The edited file is L44F1_mod.stg. Both the original and modified versions of the file are included in the raw data, with the modified one to be used for further processing. L56F1 had one anomalous value near the end. By removing the GPS fix associated with this anomaly (time 19:06:55), that portion of the line was skipped in the linearization. Both the original GPS file (L56F1.gps) and the modified one (L56F1_mod.gps) are included in this dataset.

    Person who carried out this activity:

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

    Data sources used in this process:
    • L67F1*

    Data sources produced in this process:

    • L67f1_part1*
    • L67F1_part2*

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    The navigation system used was a Lowrance 480M with an LGC-2000 Global Positioning System (GPS) antenna. The antenna was located at the anchor point for the resistivity streamer, which is also directly above the fathometer transducer mount point. The GPS system is published to be accurate to within 10 meters.

  3. How accurate are the heights or depths?

    All collected bathymetry values were collected by the 200 kHz Lowrance fathometer. The fathometer was mounted starboard side aft, directly below the GPS antenna and the resistivity streamer tow point. The Lowrance manufacturer indicates the speed of sound used by the system to convert to depths is 4800 feet/second. All values are assumed to be accurate to within 1 meter.

  4. Where are the gaps in the data? What is missing?

    All raw data collected on May 17, 2007 is available.

  5. How consistent are the relationships among the observations, including topology?

    Each data file was handled in the same manner. Modifications were made to L44F1 and L56F1 and are discussed in the processing steps.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None.
Use_Constraints:
The public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.

  1. Who distributes the data set? (Distributor 1 of 1)

    VeeAnn A. Cross
    U.S. Geological Survey
    Marine Geologist
    Woods Hole Coastal and Marine Science Center
    Woods Hole, MA 02543-1598

    (508) 548-8700 x2251 (voice)
    (508) 457-2310 (FAX)
    vatnipp@usgs.gov

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    Neither the U.S. government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    The data are provided in a WinZip compressed file. The user must have software capable of uncompressing the archive. In addition, the raw data are available in a format compatible with AGI Geosciences Marine Log Manager software. The user must have software capable of reading the AGI format in order to process these data.


Who wrote the metadata?

Dates:
Last modified: 22-Dec-2009
Metadata author:
VeeAnn A. Cross
U.S. Geological Survey
Marine Geologist
Woods Hole Coastal and Marine Science Center
Woods Hole, MA 02543-1598

(508) 548-8700 x2251 (voice)
(508) 457-2310 (FAX)
vatnipp@usgs.gov

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:


Generated by mp version 2.9.6 on Mon Mar 07 13:16:34 2011