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SandyDuck '97 Experiment: PAH2 Bipod Wave, Current, and Sonar Data

********************************************************************* FRF/USF: Shoreface Processes and Resulting Bed Response *********************************************************************

Investigators

Peter A. Howd (University of Southern Florida) and Kent K. Hathaway (USACE Field Research Facility)

Funding Sources

Office of Naval Research, Coastal Dynamics Program US Army Corps Engineer, FRF Measurements

Please contact Kent Hathaway or Peter Howd if you transfer any of these data. This document contains information about the wave, current, and sonar altimeter data collected at three cross-shore locations, in nominal depths 5.5m, 8m, and 13m. These data were collected by Kent Hathaway (USACE - FRF) and Peter Howd (USF/USGS). Each site had an instrument frame called a "bipod" that consisted of three vertically-stacked Sontek ADV's (Acoustic Doppler Velocimeters, Ocean Probe Model), a ParosScientific pressure gauge (Model Digiquartz 245A), and a DataSonics acoustic altimeter (Model SA-900). A diagram of the bipod shows the location of these instruments on the frame. Not indicated in this image is a third support pipe attached near the sonar altimeter, at approximately 30-40 degree angle, that reduced frame oscillatiions during large wave conditions.

Gauge Locations:

The three instrument-bearing frames (labeled D5, D8, and D13, based on nominal depth) were deployed at the following cross-shore locations: FRF Coordinates (m) Latitude (N) Longitude (W) Gauge ID X Y Z D D5P - pressure 889.07 581.95 -5.04 -6.19 36 11.10488 75 44.53866' D5X1/D5Y1 - bottom CM 890.39 581.11 -5.84 -6.19 36 11.10467' 75 44.53765' D5X2/D5Y2 - middle CM 890.39 581.11 -5.27 -6.16 36 11.10467' 75 44.53765' D5X3/D5Y3 - top CM 890.39 581.11 -4.45 -6.19 36 11.10467' 75 44.53765' D5S - sonar altimeter 889.61 581.99 -5.18 -6.19 36 11.10499' 75 44.53833' D8P - pressure 914.87 937.03 -7.30 -8.22 36 11.29169' 75 44.59606' D8X1/D8Y1 - bottom CM 914.87 937.03 -7.93 -8.22 36 11.29169' 75 44.59606' D8X2/D8Y2 - middle CM 914.87 937.03 -7.37 -8.22 36 11.29169' 75 44.59606' D8X3/D8Y3 - top CM 914.87 937.03 -6.65 -8.22 36 11.29169' 75 44.59606' D8S - sonar altimeter 914.87 937.03 -7.29 -8.22 36 11.29169' 75 44.59606' D13P - pressure 1604.19 909.13 -12.16 -13.22 36 11.39341' 75 44.15330' D13X1/D13Y1 - bottom CM 1604.81 908.66 -13.00 -13.22 36 11.39327' 75 44.15281' D13X2/D13Y2 - middle CM 1604.81 908.66 -12.44 -13.22 36 11.39327' 75 44.15281' D13X3/D13Y3 - top CM 1604.81 908.66 -11.72 -13.22 36 11.39327' 75 44.15281' D13S - sonar altimeter 1603.87 909.38 -12.37 -13.22 36 11.39349' 75 44.15356' where X, Y, Z, and D coordinates respectivly indicate cross-shore, longshore, gauge elevation, and nominal depth. Horizontal positions (X,Y) are given in the FRF coordinate system (m); gauge elevation (Z) and depth (D) are in meters relative to NGVD27. Gauge ID's: P=pressure, S=sonar altimeter, X/Y=ADV current meter. The FTP data files have the month, year, and station location (depth) as part of the file name. Each file has a header that labels the data columns. The first three columns, Year, Month, Day, and Time are self-explanatory; the times are EST. The other columns are the data columns and have header identifier based on the station and data type. These labels are identified below for the bipod at 13m depth (substitute D5 of D8 for the other bipods):

Statistics Files:

PUV: Wave and Current Data. Example for 13m bipod bottom ADV Label Data Type Units D13PM1 Mean pressure (gage depth) m (add FRF-coord (Z-D) to get depth) D13WH1 Significant wave height m D13WT1 Wave period (peak), from pressure s D13WD1 Wave direction, PUV bottom CM degrees CCW from onshore approach D13X1 Mean cross-shore current m/s - positive onshore directed D13Y1 Mean longshore current m/s - positive southerly directed D13CT1 UV peak period s D13ZT1 PUV-test ratio Pressure_Hmo/ADV_Hmo D13UV1 Cross-shore variance (m/s)2 D13VV1 Longshore variance (m/s)2 D13US1 Cross-shore skewness D13VS1 Longshore skewness D13NP1 Spectral signal-to-noise ratio (P) (spec peak)/(ave above high-f cutoff) D13NU1 Spectral signal-to-noise ratio (U) (spec peak)/(ave above high-f cutoff) D13NV1 Spectral signal-to-noise ratio (V) (spec peak)/(ave above high-f cutoff) D13UD1 Difference in mean pre/post edit (U) m/s D13VD1 Difference in mean pre/post edit (V) m/s D13Ud1 Difference in std pre/post edit (U) m/s D13Vd1 Difference in std pre/post edit (V) m/s D13UJ1 Number of spike/jumps edited (U) count, sum over multiple itterations D13VJ1 Number of spike/jumps edited (V) count, sum over multiple itterations D13UE1 Number of edited points ??? (U) count, sum over multiple itterations D13VE1 Number of edited points ??? (V) count, sum over multiple itterations For the middle ADV the last number in the data label would be 2 (e.g., D13PM2), and use 3 for the top ADV. Here is an example from the PAH2.SD97.100710.QC.13m.PUV1.stats file: ========================= month ------------------------- Oct ========================= year mon day time D13PM1 D13WH1 D13WT1 D13WD1 D13X1 D13Y1 D13CT1 D13ZT1 D13UV1 D13VV1 ... 1997 10 4 1000 12.77 0.33 15.06 -89 -0.008 -0.026 11.13 1.0045 0.0009 0.0000 ... 1997 10 4 1034 12.67 0.35 8.83 -97 -0.002 -0.023 4.34 0.9992 0.0012 0.0000 ... 1997 10 4 1108 12.54 0.35 15.06 -89 -0.003 -0.018 15.06 1.0992 0.0010 0.0000 ... 1997 10 4 1142 12.40 0.35 11.13 -93 -0.006 -0.014 15.06 0.9816 0.0011 0.0000 ... 1997 10 4 1216 12.25 0.32 11.13 -95 0.001 -0.009 4.34 0.9703 0.0012 0.0000 ... Sonar Data: Acoustic Altimeter and Bottom ADV This shows the format of the sonar statistics file (PAH2.SD97.sonar.stats). This file has 2Hz Datasonics data (but the gauge only updates at 1HZ, so there are redundant values) and the one sample per 3-hr collection from the bottom Sontek ADV. The ADV was not able to ping for the bottom boundary while collecting current data, thus this altimeter measurement was made between current collections. The gauge ID's are (e.g., 5m bipod): D5S1 Datasonics altimeter D5SS1 Bottom ADV measurement every three hours For the Datasonics (D5S1) the statistics format is: Year Month Day HM(hour/minute) gageID ZMaxM ZMaxP ZmaxD where, ZMaxM = depth (the one that we want to plot) ZMaxP = Percentage of pings falling into bin (can be used for QC, ~5 - 10% cutoff) ZMaxD = Distance off the bottom, sonar reading (~1m) For the Sontek ADV (D5SS1) the statistics format is: Year Month Day HM(hour/minute) gageID Dmean Peakping ADVave badping where, Dmean = depth (the one that we want to plot) Peakping = % of good pings (can be used for QC) ADVave = Distance off the bottom, sonar reading (~1m) badping = % of bad pings (use this for QC and remove records where < 0, flag -1.0) Sontek ADV Temperature Data:

Data Collection and Analysis:

These data were sampled in five contiguous records of 4096 points at 2 Hz (each record 34+ minutes). Collection times start at 0100 EST and then repeat every 3 hours (0400, 0700, ..., 2200 EST). Statistics were computed for each 34-minute record. Wave and PUV-test statistics were determined from spectral estimates using the standard Longuet-Higgins approach with 5 Fourier coefficients. Spectra were computed using the Welch method 50% overlap of 15 512-point ensembles. Wave period is from the peak in the spectrum. Wave directions are in degrees counter-clockwise from onshore, oriented relative to the pier. For example 45 degrees for waves from the northeast. Mean currents are oriented relative to the FRF coordinate system, positive cross-shore currents move onshore, positive longshore currents are southerly directed. PUV-test values are computed as the ratio of surface wave heights (linear wave theory corrected) as determined from the pressure sensor to that from a current meter. This statistic is useful for checking currrent meter data quality - high values could indicate a low response of the current meter signal due to biofouling. Sonar bottom positions are 34 minute averages of the 2-Hz data, relative to NGVD.

Timeseries Files:

The 2Hz binary files are located in the "rawBinary" directory. Each record consists of a 256-character header with gauge information (e.g., date, time, location, gain and bias, gage orientation) followed by 4096 points of 2-byte timeseries data in little endian byte order. These data files have an associared "key" file that has information for each binary record; date, time, gauge ID, record number, sequence in the five consequitive records. A fortran code snippet "PAH2.SD97.readTS.f" is provided for reading the binary files, and uses the record number to access the data file. Two sets of timeseries are available, one has been edited to remove some obvious data problems (points out of range, spikes, jumps) and have names with ".E.dat", and the unedited timeseries files, without the "E" in the name. The editing was relatively simple and the unedited files are provided for those wanting to use their own editing methods. A short description of our data editing is provided in the "PAH2.SD97.rawEditing.txt" file. The following is a list of the type of timeseries data available, using the 8m bipod in this example: ID Data Type D8P Pressure D8S Sonar altimeter measurement (Datasonics) D8T Temperature D8X1 x channel current D8Y1 y channel current D8Z1 Z channel current D8I11 intensity of beam 1 at bottom sensor D8I21 intensity of beam 2 at bottom sensor D8I31 intensity of beam 3 at bottom sensor D8R11 correlation of beam 1 at bottom sensor (makes several pings for QC) D8R21 correlation of beam 2 at bottom sensor (makes several pings for QC) D8R31 correlation of beam 3 at bottom sensor (makes several pings for QC) Key File Format: Year Month Day Time GageID Key Meanb Meana Varb Vara Interp PerRec Spikes Jumps LowC Edited 1997 10 2 1728 D5X1 10 0.0299 0.0292 0.0215 0.0212 19 0.46 3 7 0 6 1997 10 2 1728 D5X2 11 0.0324 0.0304 0.0256 0.0247 58 1.42 3 21 0 2 1997 10 2 1728 D5X3 12 0.0318 0.0310 0.0245 0.0238 32 0.78 5 10 0 2 1997 10 2 1728 D5Y1 13 0.0938 0.0940 0.0055 0.0052 57 1.39 3 42 0 2 1997 10 2 1728 D5Y2 14 0.0968 0.0984 0.0062 0.0059 106 2.59 1 69 0 2 1997 10 2 1728 D5Y3 15 0.1030 0.1033 0.0059 0.0057 84 2.05 0 55 0 2 1997 10 2 1728 D8X1 19 0.0552 0.0573 0.0204 0.0075 103 2.51 30 33 14 9 where, Key = record number in binary file Meanb = data mean before editing Meana = data mean after editing Varb = data variance before editing Vara = data variance after editing Interp = number of data points interploated PerRec = percent of record interpolated Spikes = number of spikes Jumps = number of jumps LowC = number of points with low correlation Edited = QC flag 0 = 2 = 6 = 9 = A summary plot of Octber 1997 bipod statistics shows measurements of waves, currents, and sonar altimeter at 5, 8, and 13 m depths.