NP
Nonlinear Processes in Geosciences

Atmospheric circulation

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

February 18, 2021
Four reasons for still observing cold spells despite the undeniable global climate change
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”

January 29, 2021
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”
(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]

The never-ending 2020 hurricane season

November 23, 2020
The never-ending 2020 hurricane season
Hurricane Iota approaching central America: satellite picture. Source: Wikimedia Commons.

Iota, this is the name of the last category 5 hurricane in the Atlantic Ocean. Iota is a non-name because normally hurricanes are named by NOAA starting from A to Z but when the alphabet is over, they are just identified from a letter of the Greek alphabet. Iota is a special cyclone not just because its name implies that the hurricane season is particularly rich in storms but also because of its e ...[Read More]

Can we connect the exceptional floods in France and Italy associated with the storm Alex to climate change?

October 14, 2020

The first days of October were marked by an extreme weather event: storm Alex, a cyclone of Atlantic origin, caused massive showers and thunderstorms over Provence, the Alps, Piedmont and Liguria. In these regions, numerous historical records of precipitation were broken causing the flooding of several streams and rivers in which many people lost their lives. Economic damage was also significant a ...[Read More]