An analysis of the periodically forced PP04 climate model, using the theory of non-smooth dynamical systems

IMA Journal of Applied Mathematics ◽

10.1093/imamat/hxaa039 ◽

2020 ◽

Author(s):

Kgomotso S Morupisi ◽

Chris Budd

Keyword(s):

Carbon Dioxide ◽

Dynamical Systems ◽

Climate Model ◽

Careful Analysis ◽

Dynamical Structure ◽

Discontinuous Change ◽

Carbon Dioxide Release ◽

Sudden Release ◽

Oceanic Carbon ◽

Insolation Forcing

Abstract In this paper, we perform a careful analysis of the forced PP04 model for climate change, in particular the behaviour of the ice ages. This system models the transition from a glacial to an inter-glacial state through a sudden release of oceanic carbon dioxide into the atmosphere. This process can be cast in terms of a Filippov dynamical system, with a discontinuous change in its dynamics related to the carbon dioxide release. By using techniques from the theory of non-smooth dynamical systems, we give an analysis of this model in the cases of both no insolation forcing and also periodic insolation forcing. This reveals a rich, and novel, dynamical structure to the solutions of the PP04 model. In particular, we see synchronized periodic solutions with subtle regions of existence which depend on the amplitude and frequency of the forcing. The orbits can be created/destroyed in both smooth and discontinuity-induced bifurcations. We study both the orbits and the transitions between them and make comparisons with actual climate dynamics.

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Microbial efficiency in a meromictic reservoir

Oceanological and Hydrobiological Studies ◽

10.2478/v10009-007-0047-9 ◽

2008 ◽

Vol 37 (2) ◽

Cited By ~ 2

Author(s):

Grażyna Mazurkiewicz-Boroń ◽

Teresa Bednarz ◽

Elżbieta Wilk-Woźniak

Keyword(s):

Carbon Dioxide ◽

Oxygen Consumption ◽

Release Rate ◽

Oxygen Consumption Rate ◽

Consumption Rate ◽

Metabolic Efficiency ◽

Sulphur Compounds ◽

Carbon Dioxide Release ◽

Microbial Efficiency ◽

Ion Contents

Microbial efficiency in a meromictic reservoirIndices of microbial efficiency (expressed as oxygen consumption and carbon dioxide release) were determined in the water column of the meromictic Piaseczno Reservoir (in an opencast sulphur mine), which is rich in sulphur compounds. Phytoplankton abundances were low in both the mixolimnion (up to 15 m depth) and monimolimnion (below 15 m depth). In summer and winter, carbon dioxide release was 3-fold and 5-fold higher, respectively, in the monimolimnion than in the mixolimnion. Laboratory enrichments of the sulphur substrate of the water resulted in a decrease in oxygen consumption rate of by about 42% in mixolimnion samples, and in the carbon dioxide release rate by about 69% in monimolimnion samples. Water temperature, pH and bivalent ion contents were of major importance in shaping the microbial metabolic efficiency in the mixolimnion, whilst in the monimolimnion these relationships were not evident.

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Philosophical Aspects of Astrobiology Revisited

Philosophies ◽

10.3390/philosophies6030055 ◽

2021 ◽

Vol 6 (3) ◽

pp. 55

Author(s):

Rainer E. Zimmermann

Keyword(s):

Dynamical Systems ◽

First Principles ◽

Special Form ◽

Mathematical Representation ◽

Dynamical Structure ◽

Twistor Theory ◽

Fundamental Physics ◽

Physical Universe ◽

The World ◽

Traditional Sense

Given the idea that Life as we know it is nothing but a special form of a generically underlying dynamical structure within the physical Universe, we try to introduce a concept of Life that is not only derived from first principles of fundamental physics, but also metaphysically based on philosophical assumptions about the foundations of the world. After clarifying the terminology somewhat, especially with a view to differentiating reality from modality, we give an example for a mathematical representation of what the substance of reality (in the traditional sense of metaphysics) could actually mean today, discussing twistor theory as an example. We then concentrate on the points of structural emergence by discussing the emergence of dynamical systems and of Life as we know it, respectively. Some further consequences as they relate to meaning are discussed in the end.

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The HAMMONIA Chemistry Climate Model: Sensitivity of the Mesopause Region to the 11-Year Solar Cycle and CO2 Doubling

Journal of Climate ◽

10.1175/jcli3829.1 ◽

2006 ◽

Vol 19 (16) ◽

pp. 3903-3931 ◽

Cited By ~ 197

Author(s):

H. Schmidt ◽

G. P. Brasseur ◽

M. Charron ◽

E. Manzini ◽

M. A. Giorgetta ◽

...

Keyword(s):

Carbon Dioxide ◽

Solar Cycle ◽

General Circulation ◽

Climate Model ◽

Temperature Response ◽

Circulation Model ◽

Max Planck ◽

Dynamical Processes ◽

Mesopause Region ◽

Height Range

Abstract This paper introduces the three-dimensional Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA), which treats atmospheric dynamics, radiation, and chemistry interactively for the height range from the earth’s surface to the thermosphere (approximately 250 km). It is based on the latest version of the ECHAM atmospheric general circulation model of the Max Planck Institute for Meteorology in Hamburg, Germany, which is extended to include important radiative and dynamical processes of the upper atmosphere and is coupled to a chemistry module containing 48 compounds. The model is applied to study the effects of natural and anthropogenic climate forcing on the atmosphere, represented, on the one hand, by the 11-yr solar cycle and, on the other hand, by a doubling of the present-day concentration of carbon dioxide. The numerical experiments are analyzed with the focus on the effects on temperature and chemical composition in the mesopause region. Results include a temperature response to the solar cycle by 2 to 10 K in the mesopause region with the largest values occurring slightly above the summer mesopause. Ozone in the secondary maximum increases by up to 20% for solar maximum conditions. Changes in winds are in general small. In the case of a doubling of carbon dioxide the simulation indicates a cooling of the atmosphere everywhere above the tropopause but by the smallest values around the mesopause. It is shown that the temperature response up to the mesopause is strongly influenced by changes in dynamics. During Northern Hemisphere summer, dynamical processes alone would lead to an almost global warming of up to 3 K in the uppermost mesosphere.

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Comments on “Impacts of CO2-Induced Warming on Simulated Hurricane Intensity and Precipitation: Sensitivity to the Choice of Climate Model and Convective Scheme”

Journal of Climate ◽

10.1175/jcli3592.1 ◽

2005 ◽

Vol 18 (23) ◽

pp. 5179-5182 ◽

Cited By ~ 13

Author(s):

Patrick J. Michaels ◽

Paul C. Knappenberger ◽

Christopher Landsea

Keyword(s):

Carbon Dioxide ◽

Growth Rate ◽

Tropical Cyclones ◽

Real World ◽

Climate Model ◽

Mesoscale Model ◽

Strong Relationship ◽

Sea Surface ◽

Hurricane Intensity ◽

Convective Scheme

Abstract In a simulation of enhanced tropical cyclones in a warmer world, Knutson and Tuleya make several assumptions that are not borne out in the real world. They include an unrealistically large carbon dioxide growth rate, an overly strong relationship between sea surface temperature and hurricane intensity, and the use of a mesoscale model that has shown little to no useful skill in predicting current-day hurricane intensity. After accounting for these inaccuracies, a detectable increase in Atlantic hurricane intensity in response to growing atmospheric greenhouse gas levels during this century becomes unlikely.

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Why does the climate response to greenhouse warming and greenhouse cooling differ?

10.5194/egusphere-egu21-6534 ◽

2021 ◽

Author(s):

Jennifer Kay ◽

Jason Chalmers

Keyword(s):

Carbon Dioxide ◽

Radiative Forcing ◽

Climate Model ◽

Temperature Response ◽

Greenhouse Warming ◽

Climate Response ◽

Cloud Feedbacks ◽

Surface Climate ◽

Carbon Dioxide Concentrations ◽

Radiative Feedbacks

While the long-standing quest to constrain equilibrium climate sensitivity has resulted in intense scrutiny of the processes controlling idealized greenhouse warming, the processes controlling idealized greenhouse cooling have received less attention. Here, differences in the climate response to increased and decreased carbon dioxide concentrations are assessed in state-of-the-art fully coupled climate model experiments. One hundred and fifty years after an imposed instantaneous forcing change, surface global warming from a carbon dioxide doubling (abrupt-2xCO2, 2.43 K) is larger than the surface global cooling from a carbon dioxide halving (abrupt-0p5xCO2, 1.97 K). Both forcing and feedback differences explain these climate response differences. Multiple approaches show the radiative forcing for a carbon dioxide doubling is ~10% larger than for a carbon dioxide halving. In addition, radiative feedbacks are less negative in the doubling experiments than in the halving experiments. Specifically, less negative tropical shortwave cloud feedbacks and more positive subtropical cloud feedbacks lead to more greenhouse 2xCO2 warming than 0.5xCO2 greenhouse cooling. Motivated to directly isolate the influence of cloud feedbacks on these experiments, additional abrupt-2xCO2 and abrupt-0p5xCO2 experiments with disabled cloud-climate feedbacks were run. Comparison of these &#8220;cloud-locked&#8221; simulations with the original &#8220;cloud active&#8221; simulations shows cloud feedbacks help explain the nonlinear global surface temperature response to greenhouse warming and greenhouse cooling. Overall, these results demonstrate that both radiative forcing and radiative feedbacks are needed to explain differences in the surface climate response to increased and decreased carbon dioxide concentrations.

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Abrupt CO2 release to the atmosphere under glacial and early interglacial climate conditions

Science ◽

10.1126/science.aay8178 ◽

2020 ◽

Vol 369 (6506) ◽

pp. 1000-1005

Author(s):

C. Nehrbass-Ahles ◽

J. Shin ◽

J. Schmitt ◽

B. Bereiter ◽

F. Joos ◽

...

Keyword(s):

Carbon Dioxide ◽

Intertropical Convergence Zone ◽

Meridional Overturning Circulation ◽

Before Present ◽

Freshwater Input ◽

Warm Climate ◽

Climate Conditions ◽

Carbon Dioxide Release ◽

Meridional Overturning ◽

Co2 Release

Pulse-like carbon dioxide release to the atmosphere on centennial time scales has only been identified for the most recent glacial and deglacial periods and is thought to be absent during warmer climate conditions. Here, we present a high-resolution carbon dioxide record from 330,000 to 450,000 years before present, revealing pronounced carbon dioxide jumps (CDJ) under cold and warm climate conditions. CDJ come in two varieties that we attribute to invigoration or weakening of the Atlantic meridional overturning circulation (AMOC) and associated northward and southward shifts of the intertropical convergence zone, respectively. We find that CDJ are pervasive features of the carbon cycle that can occur during interglacial climate conditions if land ice masses are sufficiently extended to be able to disturb the AMOC by freshwater input.

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On the intermittency of orographic gravity wave hotspots and its importance for middle atmosphere dynamics

10.5194/wcd-2020-21 ◽

2020 ◽

Author(s):

Ales Kuchar ◽

Petr Sacha ◽

Roland Eichinger ◽

Christoph Jacobi ◽

Petr Pisoft ◽

...

Keyword(s):

Climate Model ◽

Middle Atmosphere ◽

Model Simulation ◽

Three Dimensional ◽

Detection Algorithm ◽

Dynamics Simulation ◽

Dynamical Structure ◽

Wave Forcing ◽

Peak Detection Algorithm ◽

Opposing Effects

Abstract. When orographic gravity waves (OGWs) break, they dissipate their momentum and energy and thereby influence the thermal and dynamical structure of the atmosphere. This OGW forcing mainly takes place in the middle atmosphere. It is zonally asymmetric and strongly intermittent. So-called OGW hotspot regions have been shown to exert a large impact on the total wave forcing, in particular in the lower stratosphere (LS). Motivated by this we investigate the asymmetrical distribution of the three-dimensional OGW drag (OGWD) for selected hotspot regions in the specified dynamics simulation of the chemistry-climate model CMAM (Canadian Middle Atmosphere Model) for the period 1979–2010. As an evaluation, we first compare zonal mean OGW fluxes and GW drag (GWD) of the model simulation with observations and reanalyses in the northern hemisphere. We find an overestimation of GW momentum fluxes and GWD in the model's LS, presumably attributable to the GW parameterizations which are tuned to correctly represent the dynamics of the southern hemisphere. In the following, we define three hotspot regions which are of particular interest for OGW studies, namely the Himalayas, the Rocky Mountains and East Asia. The GW drags in these hotspot regions emerge as strongly intermittent, a result that can also quantitatively be corroborated with observational studies. Moreover, a peak-detection algorithm is applied to capture the intermittent and zonally asymmetric character of OGWs breaking in the LS and to assess composites for the three hotspot regions. This shows that LS peak OGW events can have opposing effects on the upper stratosphere and mesosphere depending on the hotspot region. Our analysis constitutes a new method for studying the intermittency of OGWs, thereby facilitating a new possibility to assess the effect of particular OGW hotspot regions on middle atmospheric dynamics.

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Enhanced humidity in SW Iberia driven by the combination of insolation and ice-sheet forcing during MIS 13 interglacial

10.5194/egusphere-egu21-11408 ◽

2021 ◽

Author(s):

Dulce Oliveira ◽

Stéphanie Desprat ◽

Qiuzhen Yin ◽

Teresa Rodrigues ◽

Filipa Naughton ◽

...

Keyword(s):

Climate Model ◽

Ice Sheets ◽

Ice Sheet ◽

Summer Rainfall ◽

Temperate Climate ◽

Precipitation Regime ◽

Northern Latitudes ◽

Evidence Model ◽

First Time ◽

Insolation Forcing

Marine Isotope Stage (MIS) 13, ~500 ky ago, represents a Quaternary interglacial of primary interest due to the unexpected enhancement of monsoon systems under a cool climate characterised by low atmospheric CO2 and larger ice volume than the present interglacial. Yet, key questions remain about its regional expression (intensity, climate variability, length) and underlying forcing factors. Here we examine the SW Iberian vegetation and terrestrial climate during MIS 13 directly compared with the sea surface temperatures using sediments from IODP Site U1385, and combine those terrestrial-marine profiles with climate-model experiments. We show for the first time that MIS 13 stands out for its large forest expansions with a reduced Mediterranean character alternating with muted forest contractions, indicating that this stage is marked by a cool-temperate climate regime with high levels of humidity. Results of our data-model approach reveal that that the dominant effect of MIS 13 insolation forcing on the regional vegetation and precipitation regime in SW Iberia is amplified by the relatively large extent of the ice-sheets in high northern latitudes. In qualitative agreement with the pollen-based evidence, model results show that ice-sheet forcing triggers an increase in the SW Iberian tree fraction along with both intensified winter and summer rainfall. We propose that the interactions between ice-sheets and major atmospheric circulation systems may have resulted in the persistent influence of the mid-latitude cells over the SW Iberian region, which led to intensified moisture availability and reduced seasonality, and, in turn, to a pronounced expansion of the temperate forest.

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