scholarly journals New Generation of Climate Models Track Recent Unprecedented Changes in Earth's Radiation Budget Observed by CERES

2020 ◽  
Vol 47 (5) ◽  
Author(s):  
Norman G. Loeb ◽  
Hailan Wang ◽  
Richard P. Allan ◽  
Timothy Andrews ◽  
Kyle Armour ◽  
...  
Keyword(s):  
Climate Models ◽  
Radiation Budget ◽  
New Generation ◽  
Earth’S Radiation Budget

scholarly journals Air Temperature and Anthropogenic Forcing: Insights from the Solid Earth

2011 ◽  
Vol 24 (2) ◽  
pp. 569-574 ◽  
Author(s):  
Jean O. Dickey ◽  
Steven L. Marcus ◽  
Olivier de Viron
Keyword(s):  
Air Temperature ◽  
Decadal Variability ◽  
Surface Air Temperature ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Length Of Day ◽  
Anthropogenic Forcing ◽  
The Core ◽  
Earth’S Radiation Budget ◽  
Gas Effect

Abstract Earth’s rotation rate [i.e., length of day (LOD)], the angular momentum of the core (CAM), and surface air temperature (SAT) all have decadal variability. Previous investigators have found that the LOD fluctuations are largely attributed to core–mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant; 2) correcting for anthropogenic effects, the correlation is present for the full span with a broadband variability centered at 78 yr; and 3) this result underscores the reality of anthropogenic temperature change, its size, and its temporal growth. The cause of this common variability needs to be further investigated and studied. Since temperature cannot affect the CAM or LOD to a sufficient extent, the results favor either a direct effect of Earth’s core-generated magnetic field (e.g., through the modulation of charged-particle fluxes, which may impact cloud formation) or a more indirect effect of some other core process on the climate—or yet another process that affects both. In all three cases, their signals would be much smaller than the anthropogenic greenhouse gas effect on Earth’s radiation budget during the coming century.

Satellite Observations of the Earth’s Radiation Budget Variability

1987 ◽  
pp. 262-267
Author(s):  
G. I. Marchuk ◽  
K. Ya. Kondratyev ◽  
V. V. Kozoderov ◽  
O. A. Avaste ◽  
O. Yu. Kärner
Keyword(s):  
Satellite Observations ◽  
Radiation Budget ◽  
Earth’S Radiation Budget

scholarly journals Clouds damp the radiative impacts of polar sea ice loss

2020 ◽  
Vol 14 (8) ◽  
pp. 2673-2686 ◽  
Author(s):  
Ramdane Alkama ◽  
Patrick C. Taylor ◽  
Lorea Garcia-San Martin ◽  
Herve Douville ◽  
Gregory Duveiller ◽  
...  
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Surface Radiation ◽  
Radiation Budget ◽  
The Arctic ◽  
Cloud Properties ◽  
Surface Radiation Budget ◽  
Cloud Radiative Effect ◽  
Radiative Impact ◽  
The Impact

Abstract. Clouds play an important role in the climate system: (1) cooling Earth by reflecting incoming sunlight to space and (2) warming Earth by reducing thermal energy loss to space. Cloud radiative effects are especially important in polar regions and have the potential to significantly alter the impact of sea ice decline on the surface radiation budget. Using CERES (Clouds and the Earth's Radiant Energy System) data and 32 CMIP5 (Coupled Model Intercomparison Project) climate models, we quantify the influence of polar clouds on the radiative impact of polar sea ice variability. Our results show that the cloud short-wave cooling effect strongly influences the impact of sea ice variability on the surface radiation budget and does so in a counter-intuitive manner over the polar seas: years with less sea ice and a larger net surface radiative flux show a more negative cloud radiative effect. Our results indicate that 66±2% of this change in the net cloud radiative effect is due to the reduction in surface albedo and that the remaining 34±1 % is due to an increase in cloud cover and optical thickness. The overall cloud radiative damping effect is 56±2 % over the Antarctic and 47±3 % over the Arctic. Thus, present-day cloud properties significantly reduce the net radiative impact of sea ice loss on the Arctic and Antarctic surface radiation budgets. As a result, climate models must accurately represent present-day polar cloud properties in order to capture the surface radiation budget impact of polar sea ice loss and thus the surface albedo feedback.

scholarly journals Improving the simulation of global aerosol with size-segregated anthropogenic number emissions

2017 ◽  
Author(s):  
Filippo Xausa ◽  
Pauli Paasonen ◽  
Risto Makkonen ◽  
Mikhail Arshinov ◽  
Aijun Ding ◽  
...  
Keyword(s):  
Particle Number ◽  
Climate Models ◽  
Climate Model ◽  
Dominant Role ◽  
Particle Diameter ◽  
Radiation Budget ◽  
Size Distributions ◽  
Anthropogenic Aerosol ◽  
Accumulation Mode ◽  
Climate Interactions

Abstract. Climate models are important tools that are used for generating climate change projections, in which aerosol-climate interactions are one of the main sources of uncertainties. In order to quantify aerosol-radiation and aerosol-cloud interactions, detailed input of anthropogenic aerosol number emissions is necessary. However, the anthropogenic aerosol number emissions are usually converted from the corresponding mass emissions in precompiled emission inventories through a very simplistic method depending uniquely on chemical composition, particle size and density, which are defined for a few very wide main source sectors. In this work, the anthropogenic particle number emissions converted from the AeroCom mass in the ECHAM-HAM climate model were replaced with the recently-formulated number emissions from the Greenhouse Gas and Air Pollution Interactions and Synergies (GAINS)-model, where the emission number size distributions vary, for example, with respect to the fuel and technology. A special attention in our analysis was put on accumulation mode particles (particle diameter dp > 100 nm) because of (i) their capability of acting as cloud condensation nuclei (CCN), thus forming cloud droplets and affecting Earth's radiation budget, and (ii) their dominant role in forming the coagulation sink and thus limiting the concentration of sub-100 nanometers particles. In addition, the estimates of anthropogenic CCN formation, and thus the forcing from aerosol-climate interactions are expected to be affected. Analysis of global particle number concentrations and size distributions reveal that GAINS implementation increases CCN concentration compared with AeroCom, with regional enhancement factors reaching values as high as 10. A comparison between modeled and observed concentrations shows that the increase in number concentration for accumulation mode particle agrees well with measurements, but it leads to a consistent underestimation of both nucleation mode and Aitken mode (dp > 100 nm) particle number concentrations. This suggests that revisions are needed in the new particle formation and growth schemes currently applied in global modeling frameworks.

Climate and the Earth's Radiation Budget

Physics Today ◽  
1989 ◽  
Vol 42 (5) ◽  
pp. 22-32 ◽  
Author(s):  
V. Ramanathan ◽  
Bruce R. Barkstrom ◽  
Edwin F. Harrison
Keyword(s):  
Radiation Budget ◽  
Earth’S Radiation Budget

scholarly journals Cloud macro-physical properties in Saharan dust laden and dust free North Atlantic trade wind regimes: A lidar study

2019 ◽  
Author(s):  
Manuel Gutleben ◽  
Silke Groß ◽  
Martin Wirth
Keyword(s):  
Physical Properties ◽  
Long Range ◽  
Climate Models ◽  
Airborne Lidar ◽  
Saharan Dust ◽  
Radiation Budget ◽  
Trade Wind ◽  
Height Distribution ◽  
Dust Transport ◽  
Shallow Marine

Abstract. Saharan dust is known to have an important impact on the atmospheric radiation budget, both directly and indirectly by changing cloud properties. However, up to now it is still an open question if elevated and long-range transported Saharan dust layers have an effect on subjacent marine trade wind cloud occurrence. Shallow trade wind clouds have a significant impact on the Earth's radiation budget and still introduce large uncertainties in climate sensitivity estimates, because of their poor representation in climate models. The Next-generation Aircraft Remote-Sensing for Validation studies (NARVAL) aimed at providing a better understanding of shallow marine trade wind clouds and their interplay with long-range transported elevated Saharan dust layers. Two airborne campaigns were conducted – the first one in December 2013 and the second one in August 2016; the latter one during the peak season of transatlantic Saharan dust transport. Airborne lidar measurements in the vicinity of Barbados performed during the second field campaign are used to investigate possible differences between shallow marine cloud macro-physical properties in dust-free regions and regions comprising elevated Saharan dust layers. The cloud top height distribution derived in dust-laden regions differs from the one derived in dust-free regions and indicates that clouds are shallower and convective development is suppressed. Furthermore, regions comprising elevated Saharan dust layers show a larger fraction of small clouds and larger cloud free regions, compared to dust-free regions. The cloud fraction in dusty regions is only 14 % compared to a fraction of 31 % in dust-free regions. Moreover, a decreasing trend of cloud fractions and cloud top heights with increasing dust layer vertical extent as well as aerosol optical depth is found.

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