oceanography

A synergy of observations: Filling the gaps in an ocean colour chlorophyll-a record

Daniel J. Ford February 20, 2026

Satellite ocean colour chlorophyll-a provides synoptic scale observations that highlight the turbulent and dynamic nature of the oceans (Credit: Daniel Ford generated from ESA OC-CCI data).

Chlorophyll-a (chl-a), as the dominant photosynthetic pigment within phytoplankton, provides an indication of the phytoplankton biomass and are essential for understanding global and regional changes in primary production in the oceans. Multiple ocean colour satellites have unlocked routine synoptical scale observations of chl-a which now extends from 1997 to the present day. Differing numbers of ...[Read More]

A Record-Breaking Indian Ocean Dipole: What Happened in 2021–2022?

Ankur Srivastava February 5, 2026

Left panel: The monthly Dipole Mode index (DMI), the Niño 3.4 index, and the relative Niño 3.4 index (RONI) from observational SST datasets: ERSST (bars), and the three-month running mean for ERSST, OISST and HadlSST (lines) for the period 2020–2022; Right Panel: A schematic illustrating the La Niña-induced anomalous Walker circulation over Indian longitudes, and the associated modulation of surface winds, Wyrtki jets and the anomalous heat content in the eastern tropical Indian Ocean.

The Indian Ocean Dipole (IOD) is generally considered a seasonal mode of variability, developing and decaying within a single year. During 2021–2022, however, negative IOD conditions persisted for approximately 19 months (Figure 1, top left), making this event the longest—and among the strongest—observed since reliable records began. This unusual persistence highlights important aspects of ocean–a ...[Read More]

How do mesoscale eddies modulate CO2 fluxes in the Southern Ocean?

Mariana Salinas Matus January 23, 2026

Mesoscale eddies and Southern Ocean carbon sink The Southern Ocean takes up more than a quarter of the anthropogenic CO₂. Its powerful westerly winds, deep overturning circulation, and intense mixing make it a major player in Earth’s climate system. But beneath this large-scale picture lies a world of swirling, dynamic structures that constantly reshape the ocean’s physical and biogeochemical prop ...[Read More]

Where Freshwater Meets the Fjord: Researching Carbon in a Changing Arctic

Maurie Keppens September 9, 2025

We sat down with Henry Henson, a PhD student at Aarhus University, whose path led from an early love of nature to studying the frontlines of climate change in the Arctic. Henry works with both Aarhus University’s Arctic Research Centre and the Greenland Climate Research Centre in Nuuk, exploring how Greenland’s coastal oceans absorb CO2 and how a warming, freshening Arctic is transforming these fr ...[Read More]