NP
Nonlinear Processes in Geosciences

Mathematics

COVID-19-related drop in anthropogenic aerosol emissions in China and corresponding cloud and climate effects

May 29, 2020
COVID-19-related drop in anthropogenic aerosol emissions in China and corresponding cloud and climate effects
Observed reduced NO2 concentration above China in February 2020. Shown is the difference between February 2020 and the average of February 2018 and 2019. Figure from https://doi.org/10.31223/osf.io/z5dm8.

While a previous blog entry dealt with the question whether we can use lessons from the nonlinear nature of climate for projections of the Covid-19 pandemic, there is now a first example of how the pandemic can teach us something on climate. The several weeks long lockdown of China made February 2020 an exceptional month in terms of air quality; aerosol emissions were tremendously reduced leading ...[Read More]

NP Interviews: the 2020 Lewis Fry Richardson Medal Valerio Lucarini

April 29, 2020
NP Interviews: the 2020 Lewis Fry Richardson Medal Valerio Lucarini
The 2020 Lewis Fry Richardson Medal Valerio Lucarini.

Today’s NP Interviews hosts the 2020 Lewis Fry Richardson Medal Valerio Lucarini. Valerio (b. Ancona, Italy, 1976) is the Director of the Centre for the Mathematics of Planet Earth and Professor of Statistical Mechanics at the University of Reading, and former Professor of Theoretical Meteorology at the University of Hamburg. His main expertise is in Climate Dynamics, Extreme Events, Statist ...[Read More]

NPG Paper of the Month: “Application of a local attractor dimension to reduced space strongly coupled data assimilation for chaotic multiscale systems”

April 23, 2020
NPG Paper of the Month: “Application of a local attractor dimension to reduced space strongly coupled data assimilation for chaotic multiscale systems”
Local dynamical properties of a segment of an example run for the coupled Lorenz system. (a) Alignment of directions of error growth plotted along the x coordinate of the ocean subsystem. Large orange stars indicate high alignment of error growth in the unstable or neutral subspaces. (b) Finite-time Lyapunov exponents (FTLEs) computed over window τ = 4. (c) Local Kaplan-Yorke dimension calculated from FTLEs. (Source: Quinn, O’Kane, and Kitsios, Application of a local attractor dimension to reduced space strongly coupled data assimilation for chaotic multiscale systems, Nonlin. Processes Geophys., 27, 51–74, 2020, https://www.nonlin-processes-geophys.net/27/51/2020/. License: https://creativecommons.org/licenses/by-nc-nd/4.0/.

This month the NPG Paper of the Month award is achieved by Courtney Quinn for her paper “Application of a local attractor dimension to reduced space strongly coupled data assimilation for chaotic multiscale systems” (https://www.nonlin-processes-geophys.net/27/51/2020/). Dr. Courtney obtained her PhD in Mathematics at the University of Exeter (UK) researching critical transitions in dynamical syst ...[Read More]

After Lorenzo and Ophelia, should we prepare European coasts for tropical storms and hurricanes?

October 15, 2019
After Lorenzo and Ophelia, should we prepare European coasts for tropical storms and hurricanes?
probability forecasts of tropical storm force winds issued by the National Hurrican Center issued on 02/10/2019. Source: https://www.nhc.noaa.gov/graphics_at3.shtml?tswind120? .

Autumn is hurricane season in the north tropics and indeed 2019 does not make exception from this point of view. After Dorian hitting Bahamas and North Carolina, the American National Hurricane Center named Lorenzo a tropical depression originating near Capo Verde. On September 25th Lorenzo became a category 1 hurricane, according to the Saffir-Simpson scale. This scale categorizes the hurricanes ...[Read More]