scholarly journals Global 3D modelling of Martian CO2 clouds

2021 ◽  
Author(s):  
Christophe Mathé ◽  
Anni Määttänen ◽  
Joachim Audouard ◽  
Constantino Listowski ◽  
Ehouarn Millour ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Martian Atmosphere ◽  
Polar Regions ◽  
Northern Latitudes ◽  
1D Model ◽  
Mesospheric Clouds ◽  
Microphysical Processes ◽  
Thermal Tides

<p>In the Martian atmosphere, carbon dioxide (CO<sub>2</sub>) clouds have been revealed by numerous instruments around Mars from the beginning of the XXI century. These observed clouds can be distinguished by two kinds involving different formation processes: those formed during the winter in polar regions located in the troposphere, and those formed during the Martian year at low- and mid-northern latitudes located in the mesosphere (Määattänen et al, 2013). Microphysical processes of formation of theses clouds are still not fully understood. However, modeling studies revealed processes necessary for their formation: the requirement of waves that perturb the atmosphere leading to a temperature below the condensation of CO<sub>2</sub> (transient planetary waves for tropospheric clouds (Kuroda et al., 20123), thermal tides (Gonzalez-Galindo et al., 2011) and gravity waves for mesospheric clouds (Spiga et al., 2012)). In the last decade, a state-of-the-art microphysical column (1D) model for CO<sub>2</sub> clouds in a Martian atmosphere was developed at Laboratoire Atmosphères, Observations Spatiales (LATMOS) (Listowski et al., 2013, 2014). We use our full microphysical model of CO<sub>2</sub> clouds formation to investigate the occurrence of these CO<sub>2</sub> clouds by coupling it with the Global Climate Model (GCM) of the Laboratoire de Météorologie Dynamique (LMD) (Forget et al., 1999). Last modeling results on Martian CO<sub>2</sub> clouds properties and their impacts on the atmosphere will be presented and be compared to observational data.</p>

scholarly journals Global 3D modelling of Martian CO2 clouds

2021 ◽  
Author(s):  
Christophe Mathé ◽  
Anni Määttänen ◽  
Joachim Audouard ◽  
Constantino Listowski ◽  
Ehouarn Millour ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Martian Atmosphere ◽  
Cloud Formation ◽  
Polar Regions ◽  
Northern Latitudes ◽  
1D Model ◽  
Mesospheric Clouds ◽  
Microphysical Processes

<p>In the Martian atmosphere, carbon dioxide (CO<sub>2</sub>) clouds have been revealed by numerous instruments around Mars from the beginning of the XXI century. These observed clouds can be distinguished by two kinds involving different formation processes: those formed during the winter in polar regions located in the troposphere, and those formed during the Martian year at low- and mid-northern latitudes located in the mesosphere (Määattänen et al, 2013). Microphysical processes of the formation of these clouds are still not fully understood. However, modeling studies revealed processes necessary for their formation: the requirement of waves that perturb the atmosphere leading to a temperature below the condensation of CO<sub>2</sub> (transient planetary waves for tropospheric clouds (Kuroda et al., 20123), thermal tides (Gonzalez-Galindo et al., 2011) and gravity waves for mesospheric clouds (Spiga et al., 2012)). In the last decade, a state-of-the-art microphysical column (1D) model for CO<sub>2</sub> clouds in a Martian atmosphere was developed at Laboratoire Atmosphères, Observations Spatiales (LATMOS) (Listowski et al., 2013, 2014). We use our full microphysical model of CO<sub>2</sub> cloud formation to investigate the occurrence of these CO<sub>2</sub> clouds by coupling it with the Global Climate Model (GCM) of the Laboratoire de Météorologie Dynamique (LMD) (Forget et al., 1999). We recently activated the radiative impact of CO<sub>2</sub> clouds in the atmosphere. Last modeling results on Martian CO<sub>2</sub> clouds properties and their impacts on the atmosphere will be presented and be compared to observational data.</p>

How detailed do cloud microphysics need to be in climate models?

2021 ◽  
Author(s):  
Ulrike Proske ◽  
Sylvaine Ferrachat ◽  
David Neubauer ◽  
Ulrike Lohmann
Keyword(s):  
Radiative Forcing ◽  
Climate Models ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Computing Time ◽  
Cloud Microphysics ◽  
Model Response ◽  
Microphysical Processes ◽  
Improved Accuracy

<p>Clouds are of major importance for the climate system, but the radiative forcing resulting from their interaction with aerosols remains uncertain. To improve the representation of clouds in climate models, the parameterisations of cloud microphysical processes (CMPs) have become increasingly detailed. However, more detailed climate models do not necessarily result in improved accuracy for estimates of radiative forcing (Knutti and Sedláček, 2013; Carslaw et al., 2018). On the contrary, simpler formulations are cheaper, sufficient for some applications, and allow for an easier understanding of the respective process' effect in the model.</p><p>This study aims to gain an understanding which CMP parameterisation complexity is sufficient through simplification. We gradually phase out processes such as riming or aggregation from the global climate model ECHAM-HAM, meaning that the processes are only allowed to exhibit a fraction of their effect on the model state. The shape of the model response as a function of the artificially scaled effect of a given process helps to understand the importance of this process for the model response and its potential for simplification. For example, if partially removing a process induces only minor alterations in the present day climate, this process presents as a good candidate for simplification. This may be then further investigated, for example in terms of computing time.<br>The resulting sensitivities to CMP complexity are envisioned to guide CMP model simplifications as well as steer research towards those processes where a more accurate representation proves to be necessary.</p><p> </p><p><br>Carslaw, Kenneth, Lindsay Lee, Leighton Regayre, and Jill Johnson (Feb. 2018). “Climate Models Are Uncertain, but We Can Do Something About It”. In: Eos 99. doi: 10.1029/2018EO093757</p><p>Knutti, Reto and Jan Sedláček (Apr. 2013). “Robustness and Uncertainties in the New CMIP5 Climate Model Projections”. In: Nature Climate Change 3.4, pp. 369–373. doi: 10.1038/nclimate1716</p>

Sulfur in the early martian atmosphere revisited: Experiments with a 3-D Global Climate Model

Icarus ◽  
2015 ◽  
Vol 261 ◽  
pp. 133-148 ◽  
Author(s):  
Laura Kerber ◽  
François Forget ◽  
Robin Wordsworth
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Martian Atmosphere

scholarly journals Mid-Pliocene global climate simulation with MRI-CGCM2.3: set-up and initial results of PlioMIP Experiments 1 and 2

2012 ◽  
Vol 5 (3) ◽  
pp. 793-808 ◽  
Author(s):  
Y. Kamae ◽  
H. Ueda
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Climate Simulation ◽  
Polar Regions ◽  
The North ◽  
Set Up

Abstract. The mid-Pliocene (3.3 to 3.0 million yr ago), a globally warm period before the Quaternary, is recently attracting attention as a new target for paleoclimate modelling and data-model synthesis. This paper reports set-ups and results of experiments proposed in Pliocene Model Intercomparison Project (PlioMIP) using a global climate model, MRI-CGCM2.3. We conducted pre-industrial and mid-Pliocene runs by using the coupled atmosphere-ocean general circulation model (AOGCM) and its atmospheric component (AGCM) for the PlioMIP Experiments 2 and 1, respectively. In addition, we conducted two types of integrations in AOGCM simulation, with and without flux adjustments on sea surface. General characteristics of differences in the simulated mid-Pliocene climate relative to the pre-industrial in the three integrations are compared. In addition, patterns of predicted mid-Pliocene biomes resulting from the three climate simulations are compared in this study. Generally, difference of simulated surface climate between AGCM and AOGCM is larger than that between the two AOGCM runs, with and without flux adjustments. The simulated climate shows different pattern between AGCM and AOGCM particularly over low latitude oceans, subtropical land regions and high latitude oceans. The AOGCM simulations do not reproduce wetter environment in the subtropics relative to the present-day, which is suggested by terrestrial proxy data. The differences between the two types of AOGCM runs are small over the land, but evident over the ocean particularly in the North Atlantic and polar regions.

scholarly journals Modelling the HDO cycle of the Martian atmosphere with the LMD Global Climate Model

2021 ◽  
Author(s):  
Margaux Vals ◽  
Loïc Rossi ◽  
Franck Montmessin ◽  
François Forget ◽  
Ehouarn Millour ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Martian Atmosphere

scholarly journals Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars

Science ◽  
2015 ◽  
Vol 347 (6222) ◽  
pp. 632-635 ◽  
Author(s):  
Jérémy Leconte ◽  
Hanbo Wu ◽  
Kristen Menou ◽  
Norman Murray
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Terrestrial Planets ◽  
Habitable Zone ◽  
Lower Mass ◽  
Solar Mass ◽  
Simple Scaling ◽  
Earth Like Planets ◽  
Thermal Tides

Planets in the habitable zone of lower-mass stars are often assumed to be in a state of tidally synchronized rotation, which would considerably affect their putative habitability. Although thermal tides cause Venus to rotate retrogradely, simple scaling arguments tend to attribute this peculiarity to the massive Venusian atmosphere. Using a global climate model, we show that even a relatively thin atmosphere can drive terrestrial planets’ rotation away from synchronicity. We derive a more realistic atmospheric tide model that predicts four asynchronous equilibrium spin states, two being stable, when the amplitude of the thermal tide exceeds a threshold that is met for habitable Earth-like planets with a 1-bar atmosphere around stars more massive than ~0.5 to 0.7 solar mass. Thus, many recently discovered terrestrial planets could exhibit asynchronous spin-orbit rotation, even with a thin atmosphere.

scholarly journals Mid-Pliocene global climate simulation with MRI-CGCM2.3: set-up and initial results of PlioMIP Experiments 1 and 2

2012 ◽  
Vol 5 (1) ◽  
pp. 383-423 ◽  
Author(s):  
Y. Kamae ◽  
H. Ueda
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Climate Simulation ◽  
Polar Regions ◽  
The North ◽  
Set Up

Abstract. The mid-Pliocene (3.3 to 3.0 million yr ago), a globally warm period before the Quaternary, is recently attracting attention as a new target for paleoclimate modelling and data-model synthesis. This paper reports set-ups and results of experiments proposed in Pliocene Model Intercomparison Project (PlioMIP) using with a global climate model, MRI-CGCM2.3. We conducted pre-industrial and mid-Pliocene runs by using of the coupled atmosphere-ocean general circulation model (AOGCM) and its atmospheric component (AGCM) for the PlioMIP Experiments 2 and 1, respectively. In addition, we conducted two types of integrations in AOGCM simulation, with and without flux adjustments on sea surface. General characteristics of differences in the simulated mid-Pliocene climate relative to the pre-industrial in the three integrations are compared in this study. Generally, difference of simulated surface climate between AGCM and AOGCM is larger than that between the two AOGCM runs, with and without flux adjustments. The simulated climate shows different pattern between AGCM and AOGCM particularly over low latitude oceans, subtropical land regions, and high latitude oceans. The AOGCM simulations do not reproduce wetter environment in the subtropics relative to the present-day, which is suggested by terrestrial proxy data. The differences between the two types of AOGCM runs are little over the land but evident over the ocean particularly in the North Atlantic and polar regions.

scholarly journals An Improved Parameterization for Simulating Arctic Cloud Amount in the CCSM3 Climate Model

2008 ◽  
Vol 21 (21) ◽  
pp. 5673-5687 ◽  
Author(s):  
Steve Vavrus ◽  
Duane Waliser
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Cloud Amount ◽  
The Arctic ◽  
Climate Simulation ◽  
Polar Regions ◽  
Climate System Model ◽  
Model Version

Abstract A simple alternative parameterization for predicting cloud fraction in the Community Climate System Model, version 3 (CCSM3) global climate model is presented. This formula, dubbed “freeezedry,” is designed to alleviate the bias of excessive low clouds during polar winter by reducing the cloud amount under very dry conditions. During winter, freezedry decreases the low cloud amount over the coldest regions in high latitudes by over 50% locally and more than 30% averaged across the Arctic. The cloud reduction causes an Arctic-wide drop of 15 W m−2 in surface cloud radiative forcing (CRF) during winter and about a 50% decrease in mean annual Arctic CRF. Consequently, wintertime surface temperatures fall by up to 4 K on land and 2–8 K over the Arctic Ocean, thus significantly reducing the model’s pronounced warm bias. Freezedry also affects CCSM3’s sensitivity to greenhouse forcing. In a transient-CO2 experiment, the model version with freezedry warms up to 20% less in the North Polar and South Polar regions (1.5- and 0.5-K-smaller warming, respectively). Paradoxically, the muted high-latitude response occurs despite a much larger increase in cloud amount with freezedry during nonsummer months (when clouds warm the surface), apparently because of the colder modern reference climate. While improving the polar climate simulation in CCSM3, freezedry has virtually no influence outside of very cold regions and has already been implemented in another climate model, the Global Environmental and Ecological Simulation of Ecological Systems, version 1 (GENESIS1). Furthermore, the simplicity of this parameterization allows it to be readily incorporated into other GCMs, many of which also suffer from excessive wintertime polar cloudiness.

Southern Ocean sea ice and its wider linkages: insights revealed from models and observations

2004 ◽  
Vol 16 (4) ◽  
pp. 387-400 ◽  
Author(s):  
CLAIRE L. PARKINSON
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Polar Region ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Polar Regions ◽  
Sea Ice Extent ◽  
Positive Feedbacks ◽  
Enhanced Sensitivity

Early conceptual models and global climate model (GCM) simulations both indicated the likelihood of an enhanced sensitivity to climate change in the polar regions, derived from the positive feedbacks brought about by snow and ice. As GCMs developed, however, the expected enhanced sensitivity has been more robust in the North Polar Region than the South Polar Region. Some recent increased-CO2 simulations, for instance, show little change in Southern Ocean sea ice extent and thickness and much less warming in the Southern Ocean region than in the sea ice regions of the Northern Hemisphere. Observations show a highly variable Southern Ocean ice cover that decreased significantly in the 1970s but, overall, has increased since the late 1970s. The increases are non-uniform, and in fact decreases occurred in the last three years of the 1979–2002 satellite record highlighted here. Regionally, the positive trends since the late 1970s are strongest in the Ross Sea, while the trends are negative in the Bellingshausen and Amundsen seas, a pattern that appears in greater spatial detail in maps of trends in the length of the sea ice season. These patterns correspond well with patterns of temperature trends, but there is a substantial way to go before they are understood (and can be modelled) in the full context of global change.

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