NP
Nonlinear Processes in Geosciences

Climate change

When weather extremes meet climate change: how do scientists attribute single events to climate change?

February 25, 2022
When weather extremes meet climate change: how do scientists attribute single events to climate change?
Tropical Cyclone Batsirai landfalled in Madagascar on February 5-6 2022, causing extended floding, visible on February 10 (right) when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite passed over. In this comparison of false-color imagery, which uses MODIS bands 7-2-1, areas flooded with sediment-laden water appear blue. The same area is shown on January 30, between recent storms (left panel). Credits: NASA Earth Observatory.

One of the main new points of the IPCC reports AR6 with respect to the previous ones is the increased confidence that global climate change induced by anthropogenic emissions is critically affecting the dynamics of weather extremes. For summer, and specifically over Europe, the AR6 report states that we are already observing prolonged periods of extremely warm conditions with increased droughts bo ...[Read More]

NPG Paper of the Month: “Comparing estimation techniques for temporal scaling in palaeoclimate time series”

December 14, 2021

The NPG paper of the month of July was awarded to Comparing estimation techniques for temporal scaling in palaeoclimate time series by Raphaël Hébert, Kira Rehfeld and Thomas Laepple (https://doi.org/10.5194/npg-28-311-2021). Raphaël Hébert is currently a post-doctoral researcher at the Alfred-Wegener-Institut in Potsdam (Germany) in the Earth System Diagnostics group of Thomas Laepple, where he a ...[Read More]

Exploring the multistable and multiscale climate system via noise

December 7, 2021

Could our present day “warm” climate turn into a frozen fully glaciated one, as if the whole Earth is a huge “snowball”? That was a question put forward independently by Mikhail Budyko and William Sellers in the late 60s [1,2] who made a first estimate of the necessary changes of incoming solar radiation, such that either the Arctic ice sheet completely melts, or the planet gets fully frozen. Base ...[Read More]

NPG Paper of the Month: “Empirical evidence of a fluctuation theorem for the wind mechanical power input into the ocean”

November 4, 2021
NPG Paper of the Month: “Empirical evidence of a fluctuation theorem for the wind mechanical power input into the ocean”
The pdf p(z,τ) (left) and the symmetry function normalised by the averaging time S(z,τ)/τ (right) as a function of the power input z for different averaging times τ (see caption). The variable τ gives the length of the averaging interval in terms of observations done every 6 hours. Data are for the recirculation area of the Atlantic subtropical gyre at a resolution of 0.5o in space and 6 hours in time for the period of 1993–2016. Note that the pdfs differ from Gaussian. The symmetry function converges to a straight line for increasing averaging periods, showing evidence of a FT. License: “Empirical evidence of a fluctuation theorem for the wind mechanical power input into the ocean".

This month the NPG Paper of the Month award is achieved by Achim Wirth for his paper “Empirical evidence of a fluctuation theorem for the wind mechanical power input into the ocean“. Achim obtained his PhD at the University of Nice (Franc), doing research on turbulence theory. He then moved to oceanography working at UCLA (USA) and Geomar (Germany). Since 2005 he holds a permanent position a ...[Read More]