## Characteristic Numbers of Salinity (independent of tides)

### From BAWiki

Graphical representation of tide independent characteristic numbers of salinity (with German text only). This graphical representation is also available in Encapsulated PostScript format.

## Contents

- 1 Motivation
- 2 Definitions for the tide-independent characteristic numbers of salinity
- 2.1 Maximum Value of Salinity (HSal)
- 2.2 Maximum valid Salinity (xHSal)
- 2.3 Minimum Value of Salinity (NSal)
- 2.4 Minimum valid Salinity (xNSal)
- 2.5 Mean Value of Salinity (MSal)
- 2.6 Maximum Salinity Difference (DSal)
- 2.7 Maximum Increase of Salinity
- 2.8 Maximum Decrease of Salinity
- 2.9 Standard Deviation of Salinity (StdAbwS)
- 2.10 Variance of Salinity (VarS)
- 2.11 Duration of High Salinity (DHSal)
- 2.12 Duration of Low Salinity (DNSal)
- 2.13 Advective Salt Transport
- 2.14 Mean Advective Salt Transport
- 2.15 Maximum Advective Salt Transport
- 2.16 Minimum Advective Salt Transport
- 2.17 Relative Frequency Distribution of Salinity (RelFreq)
- 2.18 Cumulative Frequency Distribution of Salinity (CumFreq)
- 2.19 Exceedance Frequency of Salinity Limits (ExcFreq)
- 2.20 Underflow Frequency of Salinity Limits (UndFreq)
- 2.21 Quantiles of Salinity

## Motivation

Calculation and graphic display of several tide-independent characteristic numbers of salinity can yield additional insight into salinity related phenomena of natural coastal and/or inland waters. In contrast to the computation of the tidal characteristic numbers of salinity the tide-independent numbers can be preferable 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 salinity may deviate strongly from the average (tide-dominated) conditions, as well as for the
- determination of characteristic values of salinity (e.g. HS and LS) 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 salinity values which occur during an arbitrary period one can calculate also the maximum salinity difference for this time span. This is a good indicator for the natural variability of salinity.
- From the computed times for the duration of high salinity and the duration of low salinity one can draw conclusions with respect to the impact of salinity on organisms living in the water or along the beaches.
- The variance of the time-dependent salinity evolution with respect to mean salinity can be used as an indicator for the dynamics of a natural water system.

**Analysis of tide-independent characteristic numbers of salinity data is carried through by the computer programs LZKSF and NCANALYSE.**

## Definitions for the tide-independent characteristic numbers of salinity

### Maximum Value of Salinity (HSal)

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

Example figures: maximum value of salinity.

Data analysis: LZKSF and NCANALYSE.

### Maximum valid Salinity (xHSal)

Highest valid (local) value of salinity within an arbitrary period of time, computed out of a time serie which may contain invalid data due to different reasons (drying, instrument failure, etc.).

Data analysis: NCANALYSE.

### Minimum Value of Salinity (NSal)

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

Example figures: minimum value of salinity.

Data analysis: LZKSF and NCANALYSE.

### Minimum valid Salinity (xNSal)

Lowest valid (local) value of salinity within an arbitrary period of time, computed out of a time serie which may contain invalid data due to different reasons (drying, instrument failure, etc.).

Data analysis: NCANALYSE.

### Mean Value of Salinity (MSal)

Mean value of salinity within the period of data analysis.

Example figures: mean value of salinity.

Data analysis: LZKSF and NCANALYSE.

### Maximum Salinity Difference (DSal)

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

Example figures: maximum salinity difference.

Data analysis: LZKSF and NCANALYSE.

### Maximum Increase of Salinity

Maximum increase of salinity (during one hour) within an arbitrary period of time.

Example: Maximum Increase of Salinity in the Ems Estuary.

Data analysis: LZKSF.

### Maximum Decrease of Salinity

Maximum decrease of salinity (within one hour) within an arbitrary period of time.

Example: Maximum Decrease of Salinity in the Ems Estuary.

Data analysis: LZKSF.

### Standard Deviation of Salinity (StdAbwS)

Standard deviation of salinity within the period of data analysis.

Computed for permanently flooded areas only.

Example figures: standard deviation of salinity.

Data analysis: LZKSF and NCANALYSE.

### Variance of Salinity (VarS)

Variance of salinity within the period of data analysis.

Computed for permanently flooded areas only.

Example figures: variance of salinity.

Data analysis: LZKSF and NCANALYSE.

### Duration of High Salinity (DHSal)

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

Example figures: duration of high salinity.

Data analysis: LZKSF and NCANALYSE.

### Duration of Low Salinity (DNSal)

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

Example figures: duration of low salinity.

Data analysis: LZKSF and NCANALYSE.

### Advective Salt Transport

Salt volume, which is transported through a cross section over a period of time.

Example: not available.

Data analysis: LZKSF.

### Mean Advective Salt Transport

Mean value of salt transport within a period of time.

Example: not available.

Data analysis: LZKSF.

### Maximum Advective Salt Transport

Highest value of salt transport within a period of time.

Example: not available.

Data analysis: LZKSF.

### Minimum Advective Salt Transport

Lowest value of salt transport within a period of time.

Example: not available.

Data analysis: LZKSF.

### Relative Frequency Distribution of Salinity (RelFreq)

Relative frequency of salinity within given salinity intervals.

Example figures: relative frequency distribution of salinity.

Data analysis: NCANALYSE.

### Cumulative Frequency Distribution of Salinity (CumFreq)

Cumulative frequency of salinity within given salinity intervals.

Example figures: cumulative frequency distribution of salinity.

Data analysis: NCANALYSE.

### Exceedance Frequency of Salinity Limits (ExcFreq)

Exceedance frequency of salinity limits within the period of data analysis.

Example figures: exceedance frequency of salinity limits.

Data analysis: NCANALYSE.

### Underflow Frequency of Salinity Limits (UndFreq)

Underflow frequency of salinity limits within the period of data analysis.

Example figures: underflow frequency of salinity limits.

Data analysis: NCANALYSE.

### Quantiles of Salinity

Salinity value of a time series which is not exceeded of a certain percentage of present salinity values.

Computed for permanently flooded areas only.

- a) Example figures: median of salinity Q_0.50
- b) Example figures: quantiles of salinity Q_0.01, Q_0.05, Q_0.95, Q_0.99

Data analysis: NCANALYSE.

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