## Characteristic Numbers for Wave and Sea State (independent of tides)

### From BAWiki

## Contents

- 1 Motivation
- 2 Definitions of Characteristic Numbers
- 2.1 Program NCANALYSE
- 2.1.1 Maximum Significant Wave Height
- 2.1.2 Time of Maximum Significant Wave Height
- 2.1.3 Mean Wave Period at Maximum Significant Wave Height
- 2.1.4 Peak Wave Period at Maximum Significant Wave Height
- 2.1.5 Residual Wave Direction
- 2.1.6 Mean Significant Wave Height
- 2.1.7 Standard Deviation of Significant Wave Height
- 2.1.8 Variance of Significant Wave Height
- 2.1.9 Duration of High Significant Wave Height
- 2.1.10 Duration of Low Significant Wave Height
- 2.1.11 Relative Frequency Distribution of Significant Wave Height
- 2.1.12 Cumulative Frequency Distribution of Significant Wave Height
- 2.1.13 Exceedance Frequency of Significant Wave Height
- 2.1.14 Underflow Frequency of Significant Wave Height
- 2.1.15 Quantiles of Significant Wave Height

- 2.2 Program LZKAF
- 2.2.1 Maximum Significant Wave Height
- 2.2.2 Direction for Wave with Maximum Significant Wave Height
- 2.2.3 Date and Time of Maximum Significant Wave Height
- 2.2.4 Duration of High Significant Wave Heights
- 2.2.5 Duration of Low Significant Wave Heights
- 2.2.6 Frequency Distribution of Significant Wave Heights

- 2.1 Program NCANALYSE

## Motivation

Knowledge of a spatial distribution of wave and sea state, its intensity as well as its duration, is of great use e.g. for various coastal and/or estuarine engineering problems. In this context the computation of characteristic numbers for wave and sea state may be of great importance. Characteristic numbers may also be of help if different periods in time have to be compared to evaluate differences with respect to sea and wave state.

**Automatic computation of characteristic numbers for wave and sea state is enabled using programs LZKAF and NCANALYSE.**

## Definitions of Characteristic Numbers

### Program NCANALYSE

#### Maximum Significant Wave Height

Highest (local) value of significant wave height within the period of data analysis.

Data analysis: NCANALYSE.

#### Time of Maximum Significant Wave Height

Difference in time between local time of max. significant wave height and the max. significant wave height at a reference station.

Data analysis: NCANALYSE.

#### Mean Wave Period at Maximum Significant Wave Height

Mean (local) wave period at time of (local) maximum significant wave height.

Data analysis: NCANALYSE.

#### Peak Wave Period at Maximum Significant Wave Height

Peak (local) wave period at time of (local) maximum significant wave height.

Data analysis: NCANALYSE.

#### Residual Wave Direction

Residual wave direction (computed from addition of vectors) within the period of data analysis.

Data analysis: NCANALYSE.

#### Mean Significant Wave Height

Mean significant wave height within the period of data analysis.

Data analysis: NCANALYSE.

#### Standard Deviation of Significant Wave Height

Standard deviation of significant wave height within the period of data analysis.

Only computed for permanently flooded areas.

Data analysis: NCANALYSE.

#### Variance of Significant Wave Height

Variance of significant wave height within the period of data analysis.

Only computed for permanently flooded areas.

Data analysis: NCANALYSE.

#### Duration of High Significant Wave Height

Period of the time during which local significant wave height lies above a given limit.

Data analysis: NCANALYSE.

#### Duration of Low Significant Wave Height

Period of the time during which local significant wave height lies below a given limit.

Data analysis: NCANALYSE.

#### Relative Frequency Distribution of Significant Wave Height

Relative frequency of significant wave height within given wave height intervals.

Data analysis: NCANALYSE.

#### Cumulative Frequency Distribution of Significant Wave Height

Cumulative frequency of significant wave height within given wave height intervals.

Data analysis: NCANALYSE.

#### Exceedance Frequency of Significant Wave Height

Exceedance frequency for significant wave height within the period of data analysis with respect to threshold values.

Data analysis: NCANALYSE.

#### Underflow Frequency of Significant Wave Height

Underflow frequency of significant wave height within the period of data analysis with respect to threshold values.

Data analysis: NCANALYSE.

#### Quantiles of Significant Wave Height

Significant wave height out of a time series which is not exceeded of a certain percentage of present significant wave height values.

Only computed for permanently flooded areas.

Data analysis: NCANALYSE.

### Program LZKAF

#### Maximum Significant Wave Height

Largest value of (local) significant wave height within the period of data analysis.

Example: not yet available.

#### Direction for Wave with Maximum Significant Wave Height

Direction of wave propagation at time of largest significant wave height within the period of data analysis.

Example: not yet available.

#### Date and Time of Maximum Significant Wave Height

Date and time of occurrence of (local) maximum wave height with respect to the corresponding date and time at a reference station.

Example: not yet available.

#### Duration of High Significant Wave Heights

Total period of time for which (local) significant wave height is larger as compared to a critical (upper) limit for significant wave height.

Example: not yet available.

#### Duration of Low Significant Wave Heights

Total period of time for which (local) significant wave height is smaller as compared to a critical (lower) limit for significant wave height.

Example: not yet available.

#### Frequency Distribution of Significant Wave Heights

Frequency distribution of (local) significant wave height for arbitrary wave height intervals as well as different sectors of wave direction.

Example: not yet available.

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