Program utilities
The program provides three main utilities: Autoevaluation, Parameters, and Analogs.
- Autoevaluation estimates the values of the oceanographic variables for each sample in the calibration database, allowing direct comparison between estimated and original values. In this routine, the program temporarily removes the core-top sample under analysis from the calibration set. To perform self-assessment, a copy of the calibration database must be supplied as sampling dataset, with the columns containing oceanographic and geographic variables removed.
- Parameters estimates sea-surface oceanographic variables —annual mean temperature (SST), Seasonality, and annual mean salinity (SSS)— for fossil samples in which the quantitative composition of their assemblage (taxonomic data) has been determined. By default, the program selects the 10 closest samples from the calibration dataset and calculates the weighted mean of their values according to distance.
- Analogs identifies the modern analogs in the calibration dataset most similar to each fossil sample. By default, the program selects the three closest analogs, although this number is customizable.
Paleoceanographer applies MAT by using distance algorithms as similarity operators between samples. Users may choose among four commonly used distance operators:
- Euclidean distance:
dij = (Σ (pik − pjk)²)1/2 - Manhattan (City Block) distance:
dij = Σ |pik − pjk| - Squared chord distance:
dij = Σ (pik1/2 − pjk1/2)² - Squared Euclidean distance:
dij = Σ (pik − pjk)²