Resource Description: NODC Accession Number 0044080
Online Links:
0-data/ : This directory contains the original set of directories 1-data/ : Directories and files prepared by NODC (such files are prepared if original formats are non-proprietary)
Contents of 0-data/: Directory Final Data/
files: comments: NatatoriumReport-5Feb08a.doc technical data report in MS Word NatatoriumReport-5Feb08a.pdf same in PDF
directory: Final Data/Data subdirectory: adcp/
file: HI070adc_20070823_20070830.meta configuration information HI070adc_wmo_2007_08_UTC.txt WavesMon format number 5, as follows
Updated with each burst of waves data. Ascii text, comma or space delimited line for each burst of data. Like Format 3 only it outputs a full resolution profile.
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.
files: HI070adc_hpr_2007_08all.txt for all samples, mean depth (pressure dbar) and temperature (C), see header in file HI070adc_hpr_2007_08.txt same as above for select times
The following files (*.mat): The Matlab files were provided if someone wanted to reprocess the data to look at other details, such as current profiles. The WavesMon wmo ASCII files have the current profile data but do not indicate where the surface is, or flag data above the surface. The mat files have the current profiles with data where bins at and above the surface were set to NaN. Vertically averaged currents were computed from these mat files and provided in the stats files. The WavesMon data is output hourly with each wave burst, so those files only have hourly currents. The Matlab current files have currents every 10 minutes. The mat files have extra variables from intermediate computations.
file: HI070adc_ULcur_2007_08.mat
explanation: Matlab_Description.txt
directory: Final Data/Data subdirectory: adopp/ This sub-directory contains the following files:
file comment natAdopp--23Aug2007.hdr metadata regarding instrument configuration and format explanation of the following natAdopp--23Aug2007.a1 Amplitude, beam 1 natAdopp--23Aug2007.a2 Amplitude, beam 2 natAdopp--23Aug2007.a3 Amplitude, beam 3 natAdopp--23Aug2007.v1 zonal velocity natAdopp--23Aug2007.v2 meridional velocity natAdopp--23Aug2007.v3 vertical velocity natAdopp--23Aug2007.sen ancillary sensors natAdopp--23Aug2007.prf ignore
Note, to acquire the date-time for each record in *.a1-3 and *.v1-3, use the date-time for the corresponding record (all have 1100 records) in natAdopp--23Aug2007.sen.
directory: Final Data/Data subdirectory: awac/ This subdirectory contains the following:
files comment natAwac-23Aug2007.whr metadata file with specifics of instrument configurations and format descriptions for the following files natAwac-23Aug2007.wap wave parameters and current data natAwac-23Aug2007.was wave spectrum natAwac-23Aug2007.wdr wave directional spectrum natAwac-23Aug2007.wcf Fourier coefficients natAwac-23Aug2007.wds full directional spectrum
The following files have the same first 7 fields: column 1: depth cell column 2: sample count column 3: month column 4: day column 5: year column 6: hour column 7: minute The eighth field of the following is the parameter given in the filename with units as above (speed, m/s, direction, degrees). files: natAwacCurBeam1-23Aug2007.txt Beam 1 current estimates natAwacCurBeam2-23Aug2007.txt Beam 2 current estimates natAwacCurBeam3-23Aug2007.txt Beam 3 current estimates natAwacCurDir-23Aug2007.txt Current direction natAwacCurSpeed-23Aug2007.txt Current speed natAwacHeading-23Aug2007.txt instrument heading natAwacPressure-23Aug2007.txt pressure (dbar)
directory: Final Data/Stats Statistics File Descriptions: Some of these files have a header line with an identification for each column. Wave directions are defined as the direction coming from, in degrees clockwise from true north (deg-F-TN). Current directions are the direction the current is heading in degrees clockwise from true north (deg-T-TN).
files: gpsFilt-Nat23Aug07.dat current drifters gpsFilt-Nat24Aug07.dat gpsFilt-Nat27Aug07.dat gpsFilt-Nat28Aug07.dat gpsFilt-Nat29Aug07.dat Processed current drifter data for day xx Aug 2007. Each file has all drifters deployed during the day, with 5 deployment days.
Column 1 year Column 2 month Column 3 day Column 4 time (UTC) Column 5 longitude minutes west of 157 deg W Column 6 latitude minutes north of 21 deg N Column 7 current speed (m/s) Column 8 current direction (deg-T-TN)
Example: 2007 8 24 0145 42 3 49.354833 15.824633 0.049 156.79 2007 8 24 0146 12 3 49.354500 15.823833 0.057 160.06 2007 8 24 0146 42 3 49.354133 15.822933 0.062 157.99
file: HI070adc_vacSD_2007_08.txt ADCP vertically averaged current Header: yymmdd year-month-day t_UTC time in UTC epochGMT epoch time (seconds since 1 Jan 1970, 0000 UTC) Evave east component of current, + heading towards, mm/s Nvave north component of current, + heading towards (mm/s) Spd current speed (mm/s) Dir current direction, (deg-T-TN)
Example: yymmdd t_UTC epochGMT Evave Nvave Spd Dir 20070824 0049 1187934598 -73 -74 104 225 20070824 0059 1187935198 -67 -74 100 223 20070824 0109 1187935798 -64 -70 95 223
file: natAdop.200708.23-29.stats Aquadopp currents
Header: yr year mo month da day hr hour mm minute CM current speed (m/s) CD current direction (deg-T-TN)
Example: yr mo da hr mm CM CD 2007 8 23 21 20 0.025 297 2007 8 23 21 30 0.021 308 2007 8 23 21 40 0.011 293 2007 8 23 21 50 0.027 349
file: natAwac.200708.23-29.CurFix.stats AWAC Currents processed without beam 1. All 10-minute current measurements are included.) Header: yr year mo month da day hr hour mm minute Cmf current speed (m/s) Cdf current direction (deg-T-TN)
Example: yr mo da hr mm Cmf Cdf 2007 8 23 1 0 NaN NaN 2007 8 23 1 10 NaN NaN 2007 8 23 1 19 NaN NaN 2007 8 23 1 30 NaN NaN 2007 8 23 1 40 0.186 170 2007 8 23 1 50 0.229 185 2007 8 23 2 0 0.221 183 2007 8 23 2 10 0.221 183 2007 8 23 2 20 0.221 183
file: natAwac.200708.23-29.stats Hourly AWAC wave, current, and water level
Header: yr year mo month da day hr hour mm minute Hs significant wave height (m) Tp peak wave period (s) Tm mean wave period (s) Dp peak wave direction (deg-F-TN) Dm mean wave direction (deg-F-TN) Cm current speed (m/s) Cd current direction (deg-T-TN)
Example: yr mo da hr mm Hs Tp Tm Dp Dm Depth Cm Cd 2007 8 23 2 5 0.73 12.7 6.4 213 211 5.120 0.221 183 2007 8 23 3 5 0.68 16.1 6.4 220 207 5.030 0.262 185 2007 8 23 4 5 0.70 13.8 7.1 215 211 4.950 0.205 186
Coastal and Hydraulics Laboratory, Field Research Facility POH District of the U.S. Army Engineer Research and Development CenterACKNOWLEDGEMENTS: The field data collection study of the Waikiki Natatorium documented in this report was performed for the U.S. Army Engineer District, Pacific Ocean, Honolulu (CEPOH). Mr. Thomas D. Smith was the CEPOH liaison during the study. The program was conducted by the U.S. Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory's (CHL) Field Research Facility (FRF) from 23-29 Aug 2007, under the direct supervision of Thomas W. Richardson, Director CHL, Bruce A. Ebersole, Chief, Flood and Storm Protection Division, and Brad Guay, Chief, Field Data Collection and Analysis Branch. The work was performed by Kent Hathaway and Stan Boc, with POH assistance by Thomas Smith, Jessica Podoski, and Jarrett Hara. Brian Scarborough and Jason Pipes were invaluable in the fabrication of instrument mounts and current drifters. At the time of the study, COL Richard B. Jenkins was Commander and Executive Director of ERDC. Dr. James R. Houston was Director.
A saltwater swimming pool, abandoned since the 1960's, lies seaward of the Memorial and blocks an along-shore channel cut through the reef. The pool is in a state of disrepair and options for its removal or modification are being evaluated. This report describes the measurements made to support modeling of currents around the Natatorium prior to modification. The primary concern for this study is that changes to the Natatorium pool could alter currents such that an adjoining beach could erode.
The instruments were mounted on a custom aluminum frames that were assembled on-site. These frames were designed for easy assembly, and when disassembled are compact for efficient shipping. Prior to deployment each gauge was field checked for compass corrections and barometric pressure.
The ADCP gauge was RD Instruments 1200 kHz Workhorse, bottom mounted facing upward with the sensor head approximately 0.45 m off the bottom. The frame was held to the bottom with about 95 lbs of lead weight. This gauge has four acoustic transducers for measuring currents and a pressure sensor, from which horizontal and vertical current profiles were computed at 0.2 m vertical spacing. Sampling was hourly at 2 Hz for directional wave measurements. Each wave burst was approximately 34 minute long, starting at the top of each hour, and consisted of 4096 points. There is a 0.62 m blanking distance from the transducer head, and with a 0.2 m bin width this makes the first sample 0.72 m past the transducer, or about 1.12 m off the bottom. Current profiles were collected every 10 minutes from a 300 point average.
The Nortek AWAC gauge was bottom mounted facing upward with the sensor head approximately 0.30 m off the bottom. This frame also had about 95 lbs of lead to hold it on the bottom. Similar to the ADCP, this gauge has four acoustic transducers for measuring currents and a pressure sensor, which measure horizontal and vertical current profiles. A noticeable difference is the transducer configuration, one beam is orientated vertically and three others slanted at 25 degrees. The vertical bean is termed the acoustic surface track (AST), which acts as an inverted echo sounder for measuring surface displacement. Bin spacing for the this unit was 0.5 m. Current profiles were collected at 10 minute intervals from a 300 point average (5 minutes). The unit does not simultaneously collect waves and currents, so hourly wave sampling began 5 minutes after the top of the hour. Wave sampling was at 2 Hz for directional wave measurements and 4 Hz for the AST. Each wave burst was approximately 17 minute long and consisted of 2048 points (maximum for vendor analysis package). There is a 0.4 m blanking distance from the transducer head, and with a 0.5 m bin width this makes the first sample 0.65 m past the transducer, about 0.95 m off the bottom.
The Nortek Aquadopp gauge had a right-angle head and was mounted prone with the head facing upward, that minimized the blanking distance from the bottom. About 95 lbs of lead was used to hold this frame on the bottom. The Aquadopp has three acoustic transducers for measuring horizontal and vertical current profiles and a pressure sensor. Bin spacing was 0.15 m and blanking distance was 0.2m. Current profiles were collected at 10 minute intervals from a 300 point average at 1Hz (5 minutes). With the transducer head essentially on the bottom the so the first sampled bin was approximately 0.3 m off the bottom.
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, rubber unions, hose clamps), a Garmin Geko GPS receivers, and MaxStream (model XStream-PKG-R) radio modems. Custom aluminum bands with four 1-inch pipe couples welded at 90 degree angles were constructed for attaching horizontal PVC pipes that support the sails (drag). The sails had about a half meter cross-section, approximately 1m horizontal and 0.5m vertical. The lower vertical PCV pipe (submerged) contained the modem and batteries, the upper pipe section contained the GPS receiver and radio antenna. A NEMA GPS data string was transmitted once per second from the Garmin and the Garmin internally recorded positions every 5 seconds. A customized circuit was developed that would stagger drogue radio transmissions by two seconds to eliminate interference from simultaneous one second bursts. This circuit also attached a buoy identification number to each position transmitted. The circuit has the capability for lighting a 9-element LED strobe for nighttime deployments. These GPS units were WAAS enabled and had a horizontal accuracy of about 2 m.
The drogues were initially deployed by balancing on a surfboard and paddling out to the drop-off point (Figure 10). This proved to be cumbersome and modification was made to the bottom sail attachment so it would slide upward for transport, riding in a floating ring (Figure 11). A land-based Linux laptop collected the drogue positions in real-time and displayed positions on Matlab generated plots.
Refer to the above mentioned report for details on data processing.
INSTRUMENT TYPES: bottom-fixed ADCP with depth, temperature, and wave sensors drifters
REFERENCES:
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
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| Data format: | MatLab |
|---|---|
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