OCEANLYZ Ocean Wave Analyzing Toolbox User Manual
Contents
1. Measurement properties for file waterdepthsample Properties Value File name waterdepthsample Number of recorded burst burst 5 Sampling frequency fs 10 Hz Recording duration duration This is duration of one burst 1024 second Pressure sensor height from bed heightfrombed 0 05 m 19 OCEANLYZ User Manual Applying Pressure Response Factor Dynamic pressure from wave will attenuate by moving from the water surface toward a bed Because of that data collected by the pressure sensor have lower magnitude compared to actual pressure values To fix this issue pressure data read by the pressure sensor should be divided by pressure response factor For that first pressure data should be converted to water depth as P sensor pg ds And then it should be corrected as h sensor poe Kp _ coshk ds P cosh khm Where hsensor is water depth read by the pressure sensor P is the pressure Kp is pressure response factor k is wave number h is mean water depth and d is the distance of the sensor location from bed By using a zero crossing method Kp can be calculated for every single wave and apply on each wave height or on water level time series data corresponded to each wave Other method to correct the data is by using Fast Fourier transform to convert the time series to frequency domain and then applying Kp for each frequency In that case Kp will decrease from 1 to2. Pressure Sensor Bed Figure2 Schematic sensor deployment setup To calculate the maximum frequency that Kp should be applied deep water condition can be considered as h z0r kh x Considering sensor setup as described in figure 2 it can be written h d lt or k h d 1 so k cosh x Koonin he dg EEEO _ coshk ds _ Mica P min b Gs cosh kh cosh kh SE a n Tas And maximum frequency that Kp should apply on data would be w gktanh kh 2xf gk tanh kh f _ ygktanh kh 210 8 Joch tanh Tr fmax for pressure correction 2m For the case that the pressure sensor sits on the bed i e d 0 and kh x it would be Ka pf 0 222 0 0863 cosh r g tanh x fax for pressure correction on And 21 OCEANLYZ User Manual Figures 3 and 4 show the maximum frequency that Kp should not apply beyond that Maximum Frequency that K can be Applied Frequency Hz 0 1 fi fi L fi fi i 0 0 1 02 0 3 0 4 0 5 06 0 7 0 8 0 9 1 Sensor Height Mean Water Depth Figure 3 Maximum Frequency that Kp should not applied beyond that Maximum Frequency that K can be Applied for the Sensor Sitting on the Bed T T T T T T T T T T T T T T T T T T T 0 05 i T S Se S SS P rc i Se S 65 7 SS s 85 9 Sa 10 Mean Water Depth m Figure 4 Maximum frequency that Kp should not apply beyond that for the sensor sitting on the
3. If data recorded with frequency of fs then input file has size of 8 OCEANLYZ User Manual fr length of each burst in second total number of recorded bursts 1 Data recorded in burst mode Assuming total number of recorded data points is equal to N following shows schematic of input file data point 1 data point 2 data point 3 data point N 2 data point N 1 data point N If data recorded with frequency of fr for number of hours equal to hr then input file has size of fs hr 3600 1 OCEANLYZ User Manual Functions This code has 5 functions for wave data analysis from water level data time series Water level could be in form of total depth or can be surface elevation If you use a pressure sensor for data collection and you are required to correct the data for pressure attenuation in the water column then you need to import water depth data otherwise either of water surface elevation or water depth time series can be used The provided Run m file will calculate the data for the whole time series by calling an appropriate function s but any of these function can be called by user his her own code as well Functions used in this toolbox are Function Description CalcWaveFun Transfer data between other functions WaveSpectraFun Calculate wave properties from spectral analysis WaveZerocrossingFun Calculate wave properties from
4. Description Module burst number of burst in the input file 1 8 duration duration time that data collected in each burst in second 1 8 nfft NFFT for Fast Fourier Transform 1 3 5 6 8 fs sampling frequency that data collected at in Hz 1 8 heightfrombed pressure sensor height from bed 3 4 6 7 8 fmin minimum frequency for cut off the lower part of spectra Hz 1 5 6 8 fmax maximum frequency for cut off the upper part of spectra Hz 1 5 6 8 fminpcorr minimum frequency that automated calculated fmaxpcorr can have 3 6 8 if autofmaxpcorr 1 Hz fmaxpcorr maximum frequency for applying pressure attenuation factor Hz 3 6 8 ftailcorrection frequency that diagnostic tail apply after that typically set at 1 5 6 8 2 5fm fm 1 Tm01 Hz tailpower power that diagnostic tail apply based on that 3 for shallow water 1 5 6 8 to 5 for deep water fminswell minimum frequency that swell can have it is used for Tpswell 5 8 calculation Hz fmaxswell maximum frequency that swell can have It is about 0 2 in Gulf of 5 8 Mexico Hz pressureattenuation define how to apply pressure attenuation factor 1 on without 3 6 8 correction after fmaxpcorr 2 on with constant correction after fmaxpcorr autofmaxpcorr define if to calculate fmaxpcorr and ftailcorrection based on water 3 6 8 depth or not 0 off 1 on mincutoff define to cut off the spectra below fmin 0 cutoff off 1 cutoff on 1 5 6 8 maxcutoff define to cut off the spectra beyo
5. open the file named Run m in MATLAB and modify it based on your configuration and requirement For more information on that please refer to Running section OCEANLYZ User Manual Running For running the tool box first the input file should be prepared in single column format Preparation of input file is explained in detailed in Input File section After the input file got prepared you need to open Run m file located in Ocean Wave Analyzing Toolbox folder on your computer You should set location of your input file its name in that file Also calculation method deployment properties initial values have to be set in this file After all the input parameters are set you can simply run this file in MATLAB This file will call CalcWaveFun m which is the core of data passing between functions that required for any specific calculation These processes will be done automatically and you do not need to do any adjusting Set up Run m As it is mentioned Run m has to be set up to run the code and use the toolbox To set up this file you should follow these steps 1 Set the location and name of your input file Input file should be prepared in advance based on requirement explained in nput File section 2 Choose the module that fits with your requirement Modules are set as follow Module Description Module Calculating Wave Parameters Using Spectral Analysis Me
6. the upper part of spectra ftailcorrection frequency that diagnostic tail apply after that typically set at 2 5fm fm 1 Tm01 tailpower power that diagnostic tail apply based on that 3 for shallow to 5 for deep water fminswell minimum frequency that is used for Tpswell calculation fmaxswell maximum frequency that swell can have It is about 0 2 in Gulf of Mexico mincutoff define if to cut off the spectra below fmin 0 cutoff off 1 cutoff on maxcutoff define if to cut off the spectra beyond fmax 0 cutoff off 1 cutoff on tailcorrection define if to apply diagnostic tail or not 0 off off 1 on ploton define if to plot spectra or not 0 not plot 1 plot Outputs of this function are Value Description HmO Zero Moment Wave Height m HmOsea Sea Zero Moment Wave Height m HmOswell Swell Zero Moment Wave Height m Tp Peak Wave Period second Tpsea Peak Sea Period second Tpswell Peak Swell Period second fp Peak Wave Frequency Hz f Frequency Hz fseparation Sea and Swell Separation Frequency Hz Syy Wave Surface Elevation Power Spectral Density m 2s In case that data measured by the pressure sensor data should be corrected for pressure attenuation In that case function PcorFFTFun or PcorZerocrossingFun should be called first to correct pressure water depth data first before calculating wave properties Results from either of those f
7. zero crossing PcorFFTFun Correct pressure attenuation effect using Fast Fourier transform FFT PcorZerocrossingFun Correct pressure attenuation effect using zero crossing SeaSwellFun Separate sea and swell 10 OCEANLYZ User Manual Calculating Wave Parameters Using Spectral Analysis Method WaveSpectraFun Function WaveSpectraFun m calculates wave properties using wave surface elevation power spectral density Inputs for this function are Value Description input wave data in m Input file should be in column format n 1 fs sampling frequency that data collected at in Hz duration duration time that data collected in input in each burst in second nfft NFFT for Fast Fourier Transform heightfrombed sensor height from bed fmin minimum frequency for cut off the lower part of spectra fmax maximum frequency for cut off the upper part of spectra ftailcorrection frequency that diagnostic tail apply after that typically set at 2 5fm fm 1 Tm01 tailpower power that diagnostic tail apply based on that 3 for shallow to 5 for deep water mincutoff define if to cut off the spectra below fmin or not 0 cutoff off 1 cutoff on maxcutoff define if to cut off the spectra beyond fmax or not 0 cutoff off 1 cutoff on tailcorrection define if to apply diagnostic tail or not 0 off off 1 on ploton define if to plot spectra or not 0 not plot 1 plot Outputs o
8. 0 as frequency f increases Figure 1 It means that 1 Kp will be 1 for f 0 and will increase toward infinity as the frequency increase If the Kp applies to whole frequency domain the high frequency region will have hugely large values because of very small values of Kp To avoid that lower and upper limits for frequencies should be considered where Kp is not apply on raw data out of that range Frequency Hz Figure 1 Schematic trend of Kp versus f Lower frequency limit for apply Kp mainly is the smallest frequency available in the data time series such as f 0 04 0 05 But upper frequency limit is depending on the deployment situation As it was 20 OCEANLYZ User Manual mentioned wave pressure will attenuate from the water surface toward the bed Figure 2 As the wave gets smaller its frequency increases it damps in water depth sooner Because of that there is a limit that the wave smaller than that wave with larger frequency than that limit will be never sensed by the sensor because their pressure is damped before reaching the pressure sensor In that case Kp should only apply to the range of frequencies that their pressure effect reaches the sensor location So for any case depending on deployment situation the range of frequencies that are large enough to reach the sensor should be calculated and Kp only applies in that range L 2 KC 3 i
9. OCEANLYZ Ocean Wave Analyzing Toolbox Version 1 3 MATLAB Toolbox User Manual Arash Karimpour www arashkarimpour com January 2015 OCEANLYZ User Manual Contents License Agr ement and Disclaimer ss nets nn ne Eegen EE Ae 3 CitatiON E 3 lang ge eg KEE 4 Stall LC RE a E aa a aA aae aaae ie aa aAa 4 RUNNING ee E E EE E E E a E 5 Set p Ke EE 5 APUC AE 8 Data recorded in D rst mode anna aa E a Ea aa Raa 8 Datarecorded in D rst Mode nie tienne arenae ee E paoa aE iE aE inst 9 FONCIONS miscarea aa E a a a 10 Calculating Wave Parameters Using Spectral Analysis Method WaveSpectraFun 11 Calculating Wave Parameters Using Zero Crossing Method WaveZerocrossingFun 13 Correcting Wave Pressure Data Using Fast Fourier Transform PCOrFFTFUN ccccsssccceessececessteeeeeseaes 14 Correcting Wave Pressure Data Using Linear Wave Theory PcorZerocrossingFun 16 Separating Sea and Swell SeaSwellFun iii 17 Sample UE 19 Applying Pressure Response Factor iii 20 Applying Diagnostic EC UE 23 E 24 OCEANLYZ User Manual License Agreement and Disclaimer This is free software which distributed ONLY for scientific purposes Series of tests in different conditions have been done to check liability and accuracy of the result but it is a user responsibility to check the final results for any possible err
10. bed 22 OCEANLYZ User Manual Applying Diagnostic Tail Diagnostic is used to correct the high frequency part of the wave spectrum for modeling purpose It is not recommended to use for measured data unless data is recorded with low frequency and no measured data is available for higher frequency or the noise in higher frequency influence the data In these cases higher part of the spectrum can be replaced by diagnostic tail Siadatmousavi et al 2012 as Syy F Syy rain X FE for f gt feat Where S f is water surface level power spectrum f is frequency Lan is the frequency that tail applies after that and n is power coefficient La typically set at 2 5 fn where fm 1 Tmo1 is a mean frequency Ardhuin et al 2010 Value of n depends on deployment condition but typically it is 5 for deep and 3 for shallow water for more detail refer to literature e g Kaihatu et al 2007 Siadatmousavi et al 2012 23 OCEANLYZ User Manual References Ardhuin F Rogers E Babanin A V Filipot J F Magne R Roland A amp Collard F 2010 Semiempirical dissipation source functions for ocean waves Part Definition calibration and validation Journal of Physical Oceanography 40 9 1917 1941 Kaihatu J M Veeramony J Edwards K L amp Kirby J T 2007 Asymptotic behaviour of frequency and wave number spectra of nearshore shoaling and breaking waves J Geophys Res 112 C06016 Siadatmousa
11. f this function are Value Description HmO Zero Moment Wave Height m Tm01 Wave Period from m01 second Mean Wave Period Tm02 Wave Period from m02 second Mean Zero Crossing Period Tp Peak Wave Period second fp Peak Wave Frequency Hz f Frequency Hz Syy Wave Surface Elevation Power Spectral Density m 2s In case that data measured by the pressure sensor data should be corrected for pressure attenuation In that case function PcorFFTFun or PcorZerocrossingFun should be called first to correct pressure water depth data first before calculating wave properties Results from either of those functions can be imported to this function for spectral analysis of wave parameters If provided Run file is used it will do that if a proper module is selected Please read the note in PcorFFTFun This function can be used as a standalone command in Matlab command screen or can be embedded in Matalb script file m file as Hm0 Tm01 Tm02 Tp fp f Syy WaveSpectraFun input fs duration nfft heightfrombed fmin fmax ftailcor rection tailpower 11 mincutoff maxcutoff tailcorrection ploton OCEANLYZ User Manual Example using provided sample input file HmO Tm01 Tm02 Tp fp f Syy WaveSpectraFun input 10 1024 2110 0 05 0 04 2 0 9 4 1 1 0 1 12 OCEANLYZ User Manual Calculating Wave Parameters Using Zero Crossing Method WaveZerocrossingFun Funct
12. fficient and zero crossing method Inputs for this function are Value Description input wave data in m Input file should be in column format n 1 fs sampling frequency that data collected at in Hz duration duration time that data collected in input in each burst in second h mean water level m heightfrombed sensor height from bed ploton define if to plot spectra or not 0 not plot 1 plot Output of this function is Eta Corrected Water Surface Level Time Series m Function can be used as a standalone command in Matlab command screen or can be embedded in Matalb script file m file as Eta PcorZerocrossingFun input fs duration h heightfrombed ploton Example using provided sample input file Eta PcorZerocrossingFun input 10 1024 1 07 0 05 1 16 OCEANLYZ User Manual Separating Sea and Swell SeaSwellFun Function SeaSwellFun m separate sea wave from swell wave using wave surface elevation power spectral density Inputs for this function are Value Description input wave data in m Input file should be in column format n 1 fs sampling frequency that data collected at in Hz duration duration time that data collected in input in each burst in second nfft NFFT for Fast Fourier Transform fmin minimum frequency for cut off the lower part of spectra fmax maximum frequency for cut off
13. ion WaveZerocrossingFun m calculates wave properties using upward zero crossing method Inputs for this function are Value Description input wave data in m Input file should be in column format n 1 fs sampling frequency that data collected at in Hz duration duration time that data collected in input in each burst in second ploton define if to plot spectra or not 0 not plot 1 plot Outputs of this function are Value Description Hs Significant Wave Height m Hz Zero Crossing Mean Wave Height m Tz Zero Crossing Mean Wave Period second Ts Significant Wave Period second H Wave Height Data Series m T Wave Period Data Series second In case that data measured by the pressure sensor data should be corrected for pressure attenuation first In that case function PcorFFTFun or PcorZerocrossingFun should be called first to correct pressure water depth data first before calculating wave properties Results from either of those functions can be imported to this function for zero crossing wave specifications calculation If provided Run file is used it will do that if a proper module is selected Please read the note in PcorFFTFun This function can be used as a standalone command in Matlab command screen or can be embedded in Matalb script file m file as Hs Hz 1z Ts H T WaveZerocrossingFun input fs duration ploton Examp
14. le using provided sample input file Hs Hz 1z Ts H T WaveZerocrossingFun input 10 1024 1 13 OCEANLYZ User Manual Correcting Wave Pressure Data Using Fast Fourier Transform PcorFFTFun Function PcorFFTFun corrects water level data measured by the pressure sensors using pressure response factor or pressure attenuation coefficient and Fast Fourier Transform Inputs for this function are Value Description input wave data in m Input file should be in column format n 1 fs sampling frequency that data collected at in Hz duration duration time that data collected in input in each burst in second nfft NFFT for Fast Fourier Transform h mean water depth in m heightfrombed sensor height from bed fminpcorr minimum frequency for applying pressure attenuation factor fmaxpcorr maximum frequency for applying pressure attenuation factor pressureattenuation define if to apply pressure attenuation factor or not 1 0n without correction after fmaxpcorr 2 on with constant correction after fmaxpcorr autofmaxpcorr define if to calculate fmaxpcorr and ftailcorrection based on water depth or not 0 off 1 on ploton define if to plot spectra or not 0 not plot 1 plot Output of this function is Eta Corrected Water Surface Level Time Series m Function can be used as a standalone command in Matlab command screen or can be embedded in Matalb scrip
15. nd fmax 0 cutoff off 1 cutoff 1 5 6 8 on tailcorrection define if apply tail correction or not 0 not apply 1 diagnostic tail 1 5 6 8 2 TMA Spectrum tail ploton define to plot spectra or not 0 not plot 1 plot 1 8 saveon define to save data or not 0 not save 1 save All 4 Run the Run m inside MATLAB Make sure the current folder is the one that Run o is in that folder Note1 If data were collected in continuous mode you can choose burst and duration as follow duration period of time that you want data averaged over that for example if you need wave properties reported every 15 min then duration would be 15 60 second burst total length of the time series divided by duration Burst should be rounded number So if total length of the time series divided by duration leads to decimal numbers data series should be shortened to avoid that happening OCEANLYZ User Manual Note2 In the calculation NFFT value that is set in RUN file will be used Also user can set it to be calculated automatically This should be done inside each function In that case NFFT will be set equal to the smallest power of two that is larger than or equal to the absolute value of the total number of data points in each burst This should be done manually inside that function Note3 Welch spectrum was used to calculate the spectral power density In all spectral calculation Hamming window with segment length of 256 data p
16. oints and 50 overlap between segments were used If any other values are required it should be changed manually inside that function Note4 autofmaxpcorr 1 will set the software to calculate fmaxpcorr and ftailcorrection based on water depth and sensor height from bed refer to technical notes Maximum value for calculated fmaxpcorr and ftailcorrection will be limited to the ones user set in RUN file OCEANLYZ User Manual Input File Input file that contains time series of surface level or water depth should be prepared in single file with only one column Input file should not contain any text Most of the file format such as mat txt xlsx csv can be imported by the program Following shows schematic of input file for data recorded in burst mode and continuous mode Data recorded in burst mode Assuming there are M burst of data each burst contains N data point following shows schematic of input file Burst 1 data point 1 Burst 1 data point 2 Burst 1 data point 3 Burst 1 data point N 2 Burst 1 data point N 1 Burst 1 data point N Burst 2 data point 1 Burst 2 data point 2 Burst 2 data point 3 Burst 2 data point N 2 Burst 2 data point N 1 Burst 2 data point N Burst M data point 1 Burst M data point 2 Burst M data point 3 Burst M data point N 2 Burst M data point N 1 Burst M data point N
17. ors By downloading this package user agreed that user is responsible for all the outcomes of using this package and developer does not liable and responsible in any way for any problems shortcomings errors and consequences regards of using of this package and its results for any purposes such as design and decision making process This software is AS IS package without any kind of warranty and support The developer is not liable for any type of liability such as claim or damage as a result of the use of this package Citation Please reference this document as Karimpour A 2015 OCEANLYZ Ocean Wave Analyzing Toolbox user manual http www arashkarimpour com download html OCEANLYZ User Manual Introduction OCEANLYZ Ocean Wave Analyzing Toolbox is a toolbox for analyzing the wave time series data collected by sensors in open body of water such as ocean sea and lake This toolbox contains functions that each one is suitable for a special purpose Both spectral and zero crossing methods are offered for wave analysis Functions can calculate wave properties such as zero moment wave height significant wave height mean wave height peak wave period and mean period This toolbox can correct the pressure attention effect for data selected by the pressure sensor Sea and swell can be separated and their properties can be reported Installation For using this package after you download it unzip it in any location you wish Then
18. t file m file as Eta PcorFFTFun input fs duration nfft h heightfrombed fminpcorr fmaxpcorr pressureattenuation auto fmaxpcorr ploton Example using provided sample input file Eta PcorFFTEun input 10 1024 2110 1 07 0 05 0 04 0 8 2 0 1 Note In case of using pressure attenuation correction function choosing a proper upper limit for applying the correction is essential If the upper limit is chosen unreasonably large it will lead to a wrong over estimation of the results The under estimation also can happen if it is chosen unreasonably low The waves that are large enough to influence gauge reading should be included in attenuation correction Pressure from smaller waves with high frequency will damp in the water column and do not reach the gauge location and should not be included in attenuation correction Wave height wave frequency water depth height of the gauge above the bed all play roles on if wave effect reaches down to the gauge or not So deployment situation and wave properties should be used to define the higher 14 OCEANLYZ User Manual frequency which has an effect on sensor reading which pressure correction should not be applied beyond that point 15 OCEANLYZ User Manual Correcting Wave Pressure Data Using Linear Wave Theory PcorZerocrossingFun Function PcorZerocrossingFun m corrects water level data measured by the pressure sensors using pressure response factor or pressure attenuation coe
19. thod module 1 Calculating Wave Parameters Using Zero Crossing Method module 2 Correcting Water Level Data Measured By Pressure Sensors Accounting For Pressure module 3 Attenuation In Depth By Using Fast Fourier Transform Correcting Water Level Data Measured By Pressure Sensors Accounting For Pressure module 4 Attenuation In Depth By Using Linear Wave Theory Separating Sea and Swell module 5 Correcting Water Level Data Measured By Pressure Sensors Accounting For Pressure module 6 Attenuation In Depth By Using Fast Fourier Transform and Calculating Wave Parameters Using Spectral Analysis Method Correcting Water Level Data Measured By Pressure Sensors Accounting For Pressure module 7 Attenuation In Depth By Using Linear Wave Theory and Calculating Wave Parameters Using Zero Crossing Method Correcting Wave Pressure Data Using Fast Fourier Transform and Separating Sea and module 8 Swell 3 Set the input values that define measurement properties boundary limitations and turning on and off part of the code Depends on which module is chosen some of these values are required and will be used in calculation Although all these values are not required at the same time but they cannot be left blank Preset value or any other value such as 1 can be set for the ones that are not required in that specific calculation These values are OCEANLYZ User Manual Value
20. unctions can be imported to this function for spectral analysis of wave parameters If provided Run file is used it will do that if a proper module is selected Please read the note in PcorFFTFun Function can be used as a standalone command in Matlab command screen or can be embedded in Matalb script file m file as 17 OCEANLYZ User Manual Hm0 HmOsea HmOswell Tp Tpsea Tpswell fp fseparation f Syy SeaSwellFun input fs duration nfft fmin fmax ftailcorrection tailpower fminswell fmaxswell mincutoff maxcutoff tailcorrection ploton Example using provided sample input file Hm0 HmOsea HmOswell Tp Tpswell fp fseparation f Syy SeaSwellFun input 10 1024 2110 0 04 2 0 9 4 0 1 0 25 1 1 0 1 18 OCEANLYZ User Manual Sample Files With this package two sample files are provided First file named input contains one burst of data recorded by the pressure sensor to be used as an input for any of function Second file named waterdepthsample contains five bursts of data recorded by the pressure sensor to be used as an input file while using Run file Measurement properties for file input Properties Value File name input Number of recorded burst burst 1 Sampling frequency fs 10 Hz Recording duration duration This is duration of one burst 1024 second Pressure sensor height from bed heightfrombed 0 05 m Mean water depth h 1 07 m
21. vi S M Jose F amp Stone G W 2011 On the importance of high frequency tail in third generation wave models Coastal Engineering 24
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