get_ocx_coefs: Get predefined coefficients for OCx

View source: R/CHLA_OCX.R

get_ocx_coefsR Documentation

Get predefined coefficients for OCx

Description

Library of existing optimized coefficients for the polynomial band ratio algorithm. "ocx" returns the coefficients of the global ocean colour algorithm used by NASA (as of Nov 2020) for the selected sensor. "poly1" to "poly4" return the regionally-optimized coefficients for polynomial algorithms of degrees 1 to 4 for the selected sensor, for the two available regions: nwa (Northwest Atlantic) or nep (Northeast Pacific).

Usage

get_ocx_coefs(sensor, region = "global", alg = "ocx")

Arguments

sensor

String, either modisaqua, seawifs, viirssnpp, landsat8, sentinel2, or olci

region

String, either "global" (for ocx algorithms), or "nwa" or "nep" (for ocx or poly1 to poly4)

alg

String, either "poly1", "poly2", "poly3", "poly4", "poly4v2", "ocx", "oc2", "oc3", or "oc4"

Value

Numeric vector of polynomial coefficients, from the coefficient on the lowest degree term to highest degree.

References

Standard algorithms from NASA: https://oceancolor.gsfc.nasa.gov/atbd/chlor_a/

Clay, S.; Peña, A.; DeTracey, B.; Devred, E. Evaluation of Satellite-Based Algorithms to Retrieve Chlorophyll-a Concentration in the Canadian Atlantic and Pacific Oceans. Remote Sens. 2019, 11, 2609. https://www.mdpi.com/2072-4292/11/22/2609

poly4v2 is the same as poly4, but was tuned with more HPLC in situ data (2002-2021), and with adjusted matchup criteria (satellite pass within 12 hours of sampling, 5x5 matrix around matching pixel, at least 13 valid pixels required in 5x5 matrix).


BIO-RSG/oceancolouR documentation built on April 30, 2024, 7:54 a.m.