Sea-Bird Zero-Crossing Statistics File Format
The Sea-Bird zero-crossing processing steps are:
Compute Fourier coefficients (non band averaged)
apply the linear theory dispersion transfer function to each frequency
inverse Fast Fourier transform to create surface time series
apply inverse Hanning window and adjust scale factor
zero all elements where the inverse Hanning factor > 10
perform zero-crossing analysis of the surface wave time series to create an array of individual waves and periods
sort the arrays
calculate the statistics
The zero-crossing statistic files are in the Sea-Bird format that contain 3 lines of data per record. The first line contains (starting with a '*'):
|
Item # |
Description |
|---|---|
|
1 |
Burst number |
|
2 |
Start of wave burst, seconds since 1 Jan 1989 (+ 3 days)* |
|
3 |
Wave integration time |
|
4 |
Number of points in wave burst |
|
5 |
Number of spectral estimates in each frequency band |
|
6 |
Water depth (m) |
|
7 |
Pressure sensor depth (m) |
|
8 |
Density (kg/m3 ) |
*Add 3 days since Sea-Bird program did not account for leap days (259200s).
The second line contains:
|
Item # |
Description |
|---|---|
|
1 |
Total variance of time series (m2 ) |
|
2 |
Total energy (Joules/m2 ) |
|
3 |
Average wave height (m) |
|
4 |
Average wave period (s) |
The third line contains:
|
Item # |
Description |
|---|---|
|
1 |
Maximum wave height (m) |
|
2 |
Significant wave height, H1/3 (m) (largest third) |
|
3 |
Significant period (s) (from largest third) |
|
4 |
H1/10 (m) (from largest 10%) |
|
5 |
H1/100 (m) (from largest 1%) |
If there are less than 10 waves H1/10 is set to 0.
If there are less than 100 waves H1/100 is set to 0.