# Characteristic Numbers of Potential Energy Anomaly (independent of tides)

### From BAWiki

## Motivation

Calculation and graphic display of several tide-independent characteristic numbers of potential energy anomaly (PEA) 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 potential energy anomaly 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 PEA may deviate strongly from the average (tide-dominated) conditions, as well as for the
- determination of characteristic values of PEA for an arbitrary long (or short) period of time.

**Analysis of tide-independent characteristic numbers of potential energy anomaly data is carried through by the computer program NCANALYSE.**

## Definitions for the tide-independent characteristic numbers of potential energy anomaly

### Maximum Value of PEA

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

### Maximum valid PEA

Highest valid (local) value of PEA 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.).

### Minimum Value of PEA

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

### Minimum valid PEA

Lowest valid (local) value of PEA 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.).

### Mean Value of PEA

Mean value of PEA within the period of data analysis.

### Maximum PEA Difference

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

### Standard Deviation of PEA

Standard deviation of PEA within the period of data analysis.

Computed for permanently flooded areas only.

### Variance of PEA

Variance of PEA within the period of data analysis.

Computed for permanently flooded areas only.

### Relative Frequency Distribution of PEA

Relative frequency of PEA within given PEA intervals.

### Cumulative Frequency Distribution of PEA

Cumulative frequency of PEA within given salinity intervals.

### Quantiles of PEA

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

Computed for permanently flooded areas only.

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