Four inexpensive current drogues (drifters) were designed and built at the CHL Field Research Facility (FRF) that used GPS tracking and radio telemetry for positioning. Deployments were made on 10 August and 13 September. June.
Resource Description: NODC Accession Number 0051075
Online Links:
Note: all times are in UTC
within ../data/
0-data/ : This directory contains the original set of directories and files 1-data/ : Directories and files prepared by NODC (such files are prepared if original formats are non-proprietary)
Contents of 0-data/: Directory SoutheastOahu_FieldData/adcp1/
Files: HI010adc.20050809_20050914.meta HI010adc.sum.20050809_20050916.txt Comment: Deployment summaries from instrument configuration files.
File: HI010adc_vac_2005_mm.txt (mm=month, ie, 08, 09) Comment: Vertically averaged current (VAC) by month. Uave = positive going eastward (mm/s), Vave = positive going north (mm/s).
file: readAdcpDSpec.m comment: Matlab code snippet to read directional wave spectra files (DSpec/).
subdirectory: adcp1/Dspec comment: Wave directional spectra files (reformatted) from RDI WavesMon program. One file for each hour. See the Matlab code snippet readAdcpDSpec.m. Units are m^2/Hz/Deg.
subdirectory adcp1/Fspec comment: Non-directional ADCP spectra, one file each hour Filename example: VSPspec.HIAD1.200508092100.UTC.asc This example is for 09 Aug 2005 at 2100 UTC.
Format: Columnar ASCII spectra from ADCP Velocity, Surface, and Pressure (VSP). Energy units are m^2/Hz/Deg, And frequency is in Hz.
subdirectory adcp1/Stats comment: wave and current statistics files by month (08=Aug, 09=Sep)
file: HI010adc_cur_2005_mm_pfl.mat comment: (by month, mm) Matlab format current profile data Variables: Uave1 = vertically averaged east current (mm/s) Vave1 = vertically averaged north current (mm/s) Ux1 = east current profile (cm/s) Vx1= north current profile (cm/s) depth = nominal depth of center of each bin stime = Matlab time format ASCII text files of all parameters in ../data/1-data/SoutheastOahu_FieldData/adcp1/Stats
file: HI010adc_wmo_2005_mm_UTC.txt comment: (by month, mm) Wave and current profiles, file by month, mm, columnar ASCII, one line per wave collection, space delimited. Format follows: Burst# YY MM DD HH mm ss cc Hs(m) Tp(s) Dp(deg) Depth(mm) Hmax(m) Tmean(s) bins depthlevel1Magnitude(m/s) depthlevel1Direction(deg) depthlevelNMagnitude(m/s) depthlevelNDirection(deg) Symbols: YY Year MM Month DD Day HH Hour mm Minute ss Second cc 1/100ths seconds Hs Significant Wave Height = 4*sqrt(area under the power spectrum) Tp Peak period = Wave period associated with the largest peak in the power spectrum Dp Peak Direction = peak direction at the peak period.
subdirectory adcp2/ See explanation for filenames, directory names, and formats in adcp1/
subdirectory advData/ Processed ADV files. Files listed below are for ADV-1, there are similar files for ADV-2 and 3. The ADV wave data from ViewHydra was suspect and has been removed from the dataset use adv_??.curWave.txt files (?? = y1, g2, and r3).
file: README.advFormat comment: summary of formats for files on this directory
file: adv_??config.txt comment: configuration files
file: adv_??.curWave.txt comment: Wave and curent stats with some QC data (where ?? = Gauge ID: y1, g2, or r3) See README.advFormat for details
subdirectory advData/spec comment: Columnar ASCII spectra files, one per collection per gauge (see README.advFormat).
subdirectory drogue/ comment: GPS drogue (drifter) data, 10 Aug and 13 Sep.
file: gpsNmmm.dat comment: N: track number of the drogue mmm: month (Aug or Sep); for example, gps1Aug.dat is for track-1 on 10 Aug.
columnar ASCII, with UTC time, latitude and longitude minutes (from Lat 21 degrees N and Lon 157 degrees W), drogue speed (m/s) and direction going towards (degrees positive clockwise from north).
Coastal and Hydraulics Laboratory, Field Research Facility POH District of the U.S. Army Engineer Research and Development CenterACKNOWLEDGEMENTS: The field data collection was performed for the U.S. Army Engineer District, Pacific Ocean, Honolulu (CEPOH) with support from the U.S. Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory's (CHL) Field Research Facility (FRF).
Learn of current and wave patterns in the bay for design considerations.
Deployments were on 9 Aug 2005 and retrieved on 14 Sep 2005. ADCP-2 was reprogrammed on 10 Aug so collection started a day later, and the batteries were depleted on 4 Sep, about 10 days before retrieval of the other gages.
ADV Gauges: The three ADV gages were the Sontek's Hydra model that sample a single point current velocity (U, V, and W) and contained an external pressure sensor. The instrument frame and ADV transducer are shown in Figure 3 ( report, after gauge retrieval). The sample volume for the current measurement is approximately 1-2 cm in size and about 0.17 m from the center transducer. This unit uses three beams to determine the three current components.
Current Drogues: Four inexpensive current drogues (drifters) were designed and built at the CHL Field Research Facility (FRF) that used GPS tracking and radio telemetry for positioning. They were constructed with off the shelf plumbing supplies (PVC pipe, vertical risers, rubber unions, hose clamps), a Garmin Geko GPS receivers, and MaxStream (model XStream-PKG-R) radio modems (Figure 4, report). The sails had about a one meter cross-section. The lower vertical PCV pipe (submerged) contained the modem and batteries, the upper horizontal pipe contained the GPS receiver and radio antennas. A NEMA GPS data string was transmitted once per second and the Garmin GCP unit internally recorded positions every 30 seconds. These GPS units are WAAS enabled and should have a horizontal accuracy of about 3 m. The radio tracking was partially successful- it required line of sight which was not possible to simultaneously receive drifters in the Kailua and Waimanalo Bays. Also the antennas and connectors should be more robust, two broke during deployment.
INSTRUMENT TYPES: RD Instruments Workhorse ADCPs (Acoustic Doppler Current Profilers) Sontek Hydra ADVs (Acoustic Doppler Velocimeters) current drogues (drifters)
REFERENCES:
Similar instruments and procedures are described in:
Hathaway, K. K and S. Boc, 2008. Field Data Collection Study Final
Report: Natatorium Current Study, Waikiki, HI. U.S. Army Engineering
POH District, Honolulu, HI., ERDC/CHL TR-08. 55p.
Person who carried out this activity:
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints: Dataset credit required
NOAA makes no warranty regarding these data,expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA, NESDIS, NODC and NCDDC cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
| Data format: | MatLab |
|---|---|
| Network links: |
https://www.ncei.noaa.gov/archive/accession/0051075 |
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