seasonder_findFORNullsInFOR: Find Nulls in First Order Region (FOR)

In SeaSondeR: Radial Metrics from SeaSonde HF-Radar Data

Find Nulls in First Order Region (FOR)

Description

This function locates the null point in the First Order Region (FOR) spectrum, which separates the first-order Bragg peak from second-order energy or the noise floor.

Usage

seasonder_findFORNullsInFOR(
  FOR,
  start_point_P,
  doppler_bins,
  left_region = FALSE
)

Arguments

FOR	A numeric vector representing the power spectrum in the FOR region.
start_point_P	A numeric value representing the power threshold at which the search for the null point begins.
doppler_bins	A numeric vector containing the Doppler bins corresponding to the spectrum in FOR.
left_region	A logical value indicating whether the null is being searched for in the negative Bragg region. Default is FALSE.

Details

The function follows these steps to determine the null point:

1. If left_region is TRUE, the FOR spectrum and Doppler bins are reversed.

2. The power spectrum is transformed to facilitate peak identification:

   • The absolute values of the power are taken and multiplied by -1.

   • The start_point_P threshold is also inverted.

3. The function identifies the first local maximum in the transformed spectrum that exceeds start_point_P.

4. The corresponding Doppler bin at the detected peak is returned as the null position.

The function relies on pracma::findpeaks to identify the peak.

Value

A numeric value representing the Doppler bin at the detected null position.

See Also

• seasonder_findFORNullsInSpectrum for locating nulls in a full spectrum.

• findpeaks for peak detection.

SeaSondeR documentation built on June 8, 2025, 10:50 a.m.