A Comparison of Biogeochemical Argo Sensors, Remote Sensing Systems, and Shipborne Field Fluorometers to Measure Chlorophyll a Concentrations in the Pacific Ocean off the Northern Coast of New Zealand

Accurately measuring chlorophyll a concentrations within the world's oceans is an important part of building our understanding of its underlying processes and the human impact on it, and developing tools to do this is an area of active study. Some methods used today to collect this data include in-situ fluorometers on board automated Biogeochemical Argo floats, flow-through fluorometers on board oceangoing vessels, and ocean color algorithms applied to remote sensing data. While shipborne field fluorometers are the most accurate of the three since they can be recalibrated before and after each expedition, they are limited in spatial and temporal coverage due to their dependence on expensive oceanographic research cruises. The Biogeochemical floats help to increase the coverage of fluorometer data by automating the data collection, but are known to suffer from sensor drift over time since their fluorometers cannot be serviced and calibrated regularly. Remote sensing data has by far the greatest spatial and temporal coverage of the three methods, but is known to be significantly less accurate in certain regions and is limited to surface measurements. This study compares these three measurement methods by analyzing data collected by a 10AU Field and Laboratory Fluorometer connected to a flow-through system, data from a Biogeochemical Argo float, and satellite data from the VIIRS-SNPP dataset in the same region. The results of comparisons between each of these collection methods are presented.