## Characteristic Numbers of Oxygen Concentration (independent of tides)

### From BAWiki

A graphic sketch for the definition of the various characteristic numbers of oxygen concentration is not available.

## Contents

- 1 Motivation
- 2 Definitions for the tide-independent characteristic numbers of oxygen concentration
- 2.1 Maximum Value of Oxygen Concentration
- 2.2 Minimum Value of Oxygen Concentration
- 2.3 Mean Value of Oxygen Concentration
- 2.4 Maximum Oxygen Concentration Difference
- 2.5 Standard Deviation of Oxygen Concentration
- 2.6 Variance of Oxygen Concentration
- 2.7 Duration of High Oxygen Concentration
- 2.8 Duration of Low Oxygen Concentration
- 2.9 Relative Frequency Distribution of Oxygen Concentration
- 2.10 Cumulative Frequency Distribution of Oxygen Concentration
- 2.11 Exceedance Frequency of Oxygen Concentration Limits
- 2.12 Underflow Frequency of Oxygen Concentration Limits
- 2.13 Quantiles of Oxygen Concentration

## Motivation

Calculation and graphic display of several tide-independent characteristic numbers of oxygen concentration concentration can yield additional insight into oxygen concentration concentration related phenomena of natural coastal and/or inland waters. Computation of the tide-independent numbers of oxygen concentration can be profitable used for

- natural waters which are not dominated by the tides, e.g. like the coastal waters and estuaries along the Baltic Sea coast of Germany, or in
- extreme situations, like for example periods of high or low fresh water runoff, when oxygen concentration may deviate strongly from the average (tide-dominated) conditions, as well as for the
- determination of characteristic values of oxygen concentration for an arbitrary long (or short) period of time.

In particular there are several useful applications possible for this type of data analysis:

- In addition to informations about the highest and lowest oxygen concentration values which occur during an arbitrary period one can calculate also the maximum oxygen concentration difference for this time span. This is a good indicator for the natural variability of oxygen concentration.
- From the computed times for the duration of high oxygen concentration and the duration of low oxygen concentration one can draw conclusions with respect to the impact of oxygen concentration on organisms living in the water or along the beaches.
- The variance of the time-dependent oxygen concentration evolution with respect to mean oxygen concentration can be used as an indicator for the dynamics of a natural water system.
- Quantities like relative and cumulative frequeny facilitates establishment of relationships between zones of infrequent of frequent values of oxygen concentration with different sections of a water body.

**An automatic analysis of all tide-independent characteristic numbers of oxygen concentration is carried through by the computer program NCANALYSE.**

## Definitions for the tide-independent characteristic numbers of oxygen concentration

### Maximum Value of Oxygen Concentration

Highest (local) value of oxygen concentration within the period of data analysis.

### Minimum Value of Oxygen Concentration

Lowest (local) value of oxygen concentration within the period of data analysis.

### Mean Value of Oxygen Concentration

Mean value of oxygen concentration within the period of data analysis.

### Maximum Oxygen Concentration Difference

Difference in oxygen concentration between maximum and minimum value within the period of data analysis.

### Standard Deviation of Oxygen Concentration

Standard deviation of oxygen concentration within the period of data analysis.

Computed for permanently flooded areas only.

### Variance of Oxygen Concentration

Variance of oxygen concentration within the period of data analysis.

Computed for permanently flooded areas only.

### Duration of High Oxygen Concentration

Time span for which oxygen concentration lies *above* a certain threshold within an arbitrary period of time.

### Duration of Low Oxygen Concentration

Time span for which oxygen concentration lies *below* a certain threshold within an arbitrary period of time.

### Relative Frequency Distribution of Oxygen Concentration

Relative frequency of oxygen concentration within given oxygen concentration intervals.

### Cumulative Frequency Distribution of Oxygen Concentration

Cumulative frequency of oxygen concentration within given oxygen concentration intervals.

### Exceedance Frequency of Oxygen Concentration Limits

Exceedance frequency of oxygen concentration limits within the period of data analysis.

### Underflow Frequency of Oxygen Concentration Limits

Underflow frequency of oxygen concentration limits within the period of data analysis.

### Quantiles of Oxygen Concentration

Oxygen Concentration value of a time series which is not exceeded of a certain percentage of oxygen concentration values in the serie.

Computed for permanently flooded areas only.

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