Join a section to a climatology and difference it

anomaly = value - clim_mean, matched on station, calendar month and depth bin. Cells with no baseline come back NA rather than 0 — an unsampled baseline is not a zero anomaly, and collapsing the two is how a map ends up claiming "normal" for somewhere never measured.

Usage

cc_anomaly(section, clim, stations)

Arguments

section

from cc_transect_section().

clim

from cc_climatology().

stations

from cc_transect_stations() — supplies grid_key and the month, which section does not carry.

Value

section plus clim_mean, clim_sd, clim_n, anomaly, anomaly_sd; baseline attribute carried through.

Details

anomaly_sd expresses the departure in baseline standard deviations, which is what makes a 1 °C anomaly interpretable: large in the deep, unremarkable at the surface in spring.