Nonlinear Processes in Geosciences

When carbon emissions break nature: icebergs and their feedback to climate change

Davide Faranda May 21, 2021

This image distributed by the European Space Agency (ESA) on May 20, 2021 shows a view of the A-76 iceberg off the Ronne sea ice in the Weddell Sea, Antarctica. It was captured by the Copernicus Sentinel-1 mission. Credits: ESA.

The largest iceberg in the world, named A-76, about 170 km long and 25 km wide, is drifting away from the Ronne pack ice in Antarctica. A76, originally spotted by the British Antarctic Survey (BAS), a British polar research organization with a base nearby, will wander and melt in the Weddell Sea, according to a statement released Wednesday, May 20, by the European Space Agency. Several studies are ...[Read More]

NPG Paper of the Month: “Ordering of trajectories reveals hierarchical finite-time coherent sets in Lagrangian particle data: detecting Agulhas rings in the South Atlantic Ocean”

David Wichmann March 16, 2021

Result of the OPTICS algorithm applied to the trajectories modelled in the Bickley Jet model flow. (a), (d) and (g) show the reachability plot with different DBSCAN clustering results, indicated by the black horizontal line. The corresponding clustering results of each choice of DBSCAN parameter is shown on the right of the reachability plots for different times. Grey particles correspond to noise. Axis units in the centre and right column are in 1000 km.

The February 2021 NPG Paper of the Month award goes David Wichmann and his co-authors for their paper “Ordering of trajectories reveals hierarchical finite-time coherent sets in Lagrangian particle data: detecting Agulhas rings in the South Atlantic Ocean“. Understanding the transport of tracers and particulates is an important topic in oceanography and in fluid dynamics in general. Th ...[Read More]

Four reasons for still observing cold spells despite the undeniable global climate change

Davide Faranda February 18, 2021

Stravinsky fountain, near the Centre Pompidou (Paris) frozen by the cold wave of 2021.

The winter of 2020-2021 has been characterized by various cold waves affecting – at different times – Western and Eastern Europe and North America. The most striking pictures show Madrid covered by up to 40 cm of fresh snow, frozen Thames near London and Canal St Martin in Paris, heavy snow in Amsterdam and even on the Eolian Islands, just offshore Sicily. At first this seems contradi ...[Read More]

The most-read NPG 2020 paper: “Effects of upwelling duration and phytoplankton growth regime on dissolved-oxygen levels in an idealized Iberian Peninsula upwelling system”

Tommaso Alberti January 29, 2021

(a) Snapshot of dissolved oxygen distribution in the upwelling front instabilities for the ECS simulation (γ is the Okubo-Weiss criterion). (b) Dissolved Oxygen budget in the idealized Iberian Peninsula Upwelling System. Net value is the sum of Physical, Biological and Atmospheric processes that change oxygen concentration levels. Physics accounts for the effect of upwelled subsurface waters and offshore transport by upwelling front instabilities. Biology term accounts for oxygen photosynthetic production and community respiration. Simulations performed are ECS (short upwelling season with enhanced phytoplankton growth), ECC (long upwelling season with enhanced phytoplankton growth), NCC (long upwelling season with neutral phytoplankton growth) and LCC (long upwelling season with limited phytoplankton growth). License: Effects of upwelling duration and phytoplankton growth regime on dissolved-oxygen levels in an idealized Iberian Peninsula upwelling system.

An emerging problem brought by climate change is the on-going deoxygenation of the world’s oceans. The fact that concentrations of dissolved oxygen have been/are declining in both open-ocean and coastal waters is becoming a major scientific and societal concern raised in the Kiel Declaration and in the IUCN (International Union for Conservation of Nature) 2019 report. Lower levels of dissolved oxy ...[Read More]