scholarly journals Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications

2013 ◽  
Vol 17 (7) ◽  
pp. 2873-2892 ◽  
Author(s):  
A. Kleidon ◽  
M. Renner
Keyword(s):  
Radiative Forcing ◽  
Atmospheric Transport ◽  
Hydrologic Cycle ◽  
Earth System ◽  
The Earth ◽  
Atmospheric Motion ◽  
Set Up ◽  
Thermodynamic Limits ◽  
Analytical Expressions

Abstract. The hydrologic cycle results from the combination of energy conversions and atmospheric transport, and the laws of thermodynamics set limits to both. Here, we apply thermodynamics to derive the limits of the strength of hydrologic cycling within the Earth system and about the properties and processes that shape these limits. We set up simple models to derive analytical expressions of the limits of evaporation and precipitation in relation to vertical and horizontal differences in solar radiative forcing. These limits result from a fundamental trade-off by which a greater evaporation rate reduces the temperature gradient and thus the driver for atmospheric motion that exchanges moistened air from the surface with the drier air aloft. The limits on hydrologic cycling thus reflect the strong interaction between the hydrologic flux, motion, and the driving gradient. Despite the simplicity of the models, they yield estimates for the limits of hydrologic cycling that are within the observed magnitude, suggesting that the global hydrologic cycle operates near its maximum strength. We close with a discussion of how thermodynamic limits can provide a better characterization of the interaction of vegetation and human activity with hydrologic cycling.

scholarly journals Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications

2013 ◽  
Vol 10 (3) ◽  
pp. 3187-3236 ◽  
Author(s):  
A. Kleidon ◽  
M. Renner
Keyword(s):  
Radiative Forcing ◽  
Atmospheric Transport ◽  
Hydrologic Cycle ◽  
Earth System ◽  
The Earth ◽  
Atmospheric Motion ◽  
Set Up ◽  
Thermodynamic Limits ◽  
Analytical Expressions

Abstract. The hydrologic cycle results from the combination of energy conversions and atmospheric transport, and the laws of thermodynamics set limits to both. Here, we apply thermodynamics to derive the limits of the strength of hydrologic cycling within the Earth system and the properties and processes that shape these limits. We set up simple models to derive analytical expressions of the limits of evaporation and precipitation in relation to vertical and horizontal differences in solar radiative forcing. These limits result from a fundamental trade-off by which a greater evaporation rate reduces the temperature gradient and thus the driver for atmospheric motion that exchanges moistened air from the surface with the drier air aloft. The limits on hydrologic cycling thus reflect the strong interaction between the hydrologic flux, motion, and the driving gradient. Despite the simplicity of the models, they yield estimates for the limits of hydrologic cycling that are within the observed magnitude, suggesting that the global hydrologic cycle operates near its maximum strength. We close with a discussion of how thermodynamic limits can provide a better characterization of the interaction of vegetation and human activity with hydrologic cycling.

scholarly journals First interactions with the hydrologic cycle determine pyrogenic carbon's fate in the Earth system

2020 ◽  
Vol 45 (10) ◽  
pp. 2394-2398
Author(s):  
Caroline Ann Masiello ◽  
Asmeret Asefaw Berhe
Keyword(s):  
Hydrologic Cycle ◽  
Earth System ◽  
The Earth

scholarly journals Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing

2017 ◽  
Author(s):  
Steven J. Lade ◽  
Jonathan F. Donges ◽  
Ingo Fetzer ◽  
John M. Anderies ◽  
Christian Beer ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Model Test ◽  
Global Climate ◽  
Earth System ◽  
Planetary Boundaries ◽  
Cycle Model ◽  
Carbon Cycle Model ◽  
The Earth ◽  
Analytical Expressions ◽  
Earth System Models

Abstract. Changes to climate-carbon cycle feedbacks may significantly affect the Earth System’s response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth System Models (ESMs). Here, we construct a stylized global climate-carbon cycle model, test its output against complex ESMs, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon-cycle feedbacks and the operation of the carbon cycle. We use our results to analytically study the relative strengths of different climate-carbon cycle feedbacks and how they may change in the future, as well as to compare different feedback formalisms. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the Planetary Boundaries, that are currently too uncertain to be included in complex ESMs.

scholarly journals The effect of optically thin cirrus clouds on solar radiation in Camagüey, Cuba

2011 ◽  
Vol 11 (3) ◽  
pp. 8777-8799
Author(s):  
B. Barja ◽  
J. C. Antuña
Keyword(s):  
Solar Radiation ◽  
Radiative Forcing ◽  
Near Infrared ◽  
Local Heating ◽  
Spectral Band ◽  
Solar Spectrum ◽  
Cirrus Clouds ◽  
Radiation Budget ◽  
Earth System ◽  
The Earth

Abstract. Cirrus clouds play a key role in the radiation budget of the Earth system. They are an important aspect in the climate system, as they interact with the atmospheric radiation field. They control both the solar radiation that reaches the Earth surface and the longwave radiation that leaves the Earth system. The feedback produced by cirrus clouds in climate is not well understood. Therefore it is necessary to improve the understanding and characterization of the radiative forcing of cirrus clouds. We analyze the effect of optically thin cirrus clouds characterized with the lidar technique in Camagüey, Cuba, on solar radiation, by numerical simulation. Nature and amplitude of the effect of cirrus clouds on solar radiation is evaluated. Cirrus clouds have a cooling effect in the solar spectrum at the Top of the Atmosphere (TOA) and at the surface (SFC). The daily mean value of solar cirrus cloud radiative forcing (SCRF) has an average value of −9.1 W m−2 at TOA and −5.6 W m−2 at SFC. The cirrus clouds also have a local heating effect on the atmospheric layer where they are located. Cirrus clouds have mean daily values of heating rates of 0.63 K day−1 with a range between 0.35 K day−1 and 1.24 K day−1. The principal effect is in the near infrared spectral band of the solar spectrum. There is a linear relation between SCRF and cirrus clouds optical depth (COD), with −30 W m−2 COD−1 and −26 W m−2 COD−1, values for the slopes of the fits at the TOA and SFC, respectively in the broadband solar spectrum. Also there is a relation between the solar zenith angle and cirrus clouds radiative forcing displayed in the diurnal cycle.

scholarly journals Biogeochemical Consequences of Ocean Acidification and Feedbacks to the Earth System

2011 ◽  
Author(s):  
Marion Gehlen ◽  
Nicolas Gruber
Keyword(s):  
Ocean Acidification ◽  
Radiative Forcing ◽  
Biogeochemical Cycles ◽  
Biological Pump ◽  
Earth System ◽  
Carbonate Chemistry ◽  
Emission Pathway ◽  
The Earth ◽  
Indirect Impacts ◽  
Active Substances

By the year 2008, the ocean had taken up approximately 140 Gt carbon corresponding to about a third of the total anthropogenic CO2 emitted to the atmosphere since the onset of industrialization (Khatiwala et al. 2009 ). As the weak acid CO2 invades the ocean, it triggers changes in ocean carbonate chemistry and ocean pH (see Chapter 1). The pH of modern ocean surface waters is already 0.1 units lower than in pre-industrial times and a decrease by 0.4 units is projected by the year 2100 in response to a business-as- usual emission pathway (Caldeira and Wickett 2003). These changes in ocean carbonate chemistry are likely to affect major ocean biogeochemical cycles, either through direct pH effects or indirect impacts on the structure and functioning of marine ecosystems. This chapter addresses the potential biogeochemical consequences of ocean acidification and associated feedbacks to the earth system, with focus on the alteration of element fluxes at the scale of the global ocean. The view taken here is on how the different effects interact and ultimately alter the atmospheric concentration of radiatively active substances, i.e. primarily greenhouse gases such as CO2 and nitrous oxide (N2O). Changes in carbonate chemistry have the potential for interacting with ocean biogeochemical cycles and creating feedbacks to climate in a myriad of ways (Box 12.1). In order to provide some structure to the discussion, direct and indirect feedbacks of ocean acidification on the earth system are distinguished. Direct feedbacks are those which directly affect radiative forcing in the atmosphere by altering the air–sea flux of radiatively active substances. Indirect feedbacks are those that first alter a biogeochemical process in the ocean, and through this change then affect the air–sea flux and ultimately the radiative forcing in the atmosphere. For example, when ocean acidification alters the production and export of organic matter by the biological pump, then this is an indirect feedback. This is because a change in the biological pump alters radiative forcing in the atmosphere indirectly by first changing the nearsurface concentrations of dissolved inorganic carbon and total alkalinity.

Is there hope for reducing the uncertainty associated with aerosols in climate projections? 

2021 ◽  
Author(s):  
Ilona Riipinen ◽  
Annica Ekman ◽  
Matthew Salter ◽  
Karoliina Pulkkinen ◽  
Keyword(s):  
Knowledge Transfer ◽  
Radiative Forcing ◽  
Aerosol Particles ◽  
Scientific Understanding ◽  
Climate Projections ◽  
Earth System ◽  
Aerosol Cloud ◽  
The Earth ◽  
Aerosol Cloud Interactions ◽  
Aerosol Emissions

<p>Together with imminent climate action, building a sustainable future for the humanity requires striving for healthier environments. Atmospheric aerosol particles (also referred to as particulate matter, PM) play a key role in defining the air that the future generations will breathe but also the climates they live in, PM being an important short-lived climate forcer but also a key component of air quality and global environmental health hazard. The contribution of aerosol particles has been a key uncertainty in estimates of the Earth’s radiative forcing since the establishment of the Intergovernmental Panel for Climate Change (IPCC) and still remains as the single largest quoted source of uncertainty in the anthropogenic climate forcing during the industrial period. In the latest assessment by the IPCC, the radiative forcing by aerosol particles has been estimated to be -0.45 W m-2 (between -0.95 and 0.05 W m-2) for aerosol-radiation interactions (RFari) and -0.45 W m-2 (between -1.25 and 0 W m-2) for aerosol-cloud interactions (RFaci). Recent reviews indicate no significant reduction in the uncertainty. The large range of possible aerosol forcing values has serious consequences for climate projections and therefore developing strategies for reaching Paris agreement targets. It is currently not possible to say if a reduction in aerosol emissions due to air pollution mitigation and a phase-out of aerosol emissions will result in a noticeable increase in global mean temperature  or in a negligible climate effect. We will discuss the components and reasons of this uncertainty, focusing on those that are important for aerosol-cloud interactions. We will identify critical bottlenecks in 1) scientific understanding of fundamental aerosol and cloud microphysical processes; 2) method development for improving the understanding of aerosol, cloud, and aerosol-cloud processes as well as their representation in Earth System Models (ESMs); and 3) knowledge transfer within and between the relevant research communities. We will argue for key actions to overcome these bottlenecks, giving examples of good practices for breaking new ground in this long-standing problem that continues to intrigue the atmospheric and climate science communities. Besides enhancing the scientific understanding of the Earth system within the realm of natural science based on multiple lines of evidence, and developing novel (e.g. machine learning –based) methodologies for analyzing existing observational data and model output, we call for additional perspectives from social science and humanities on the communication and knowledge transfer practices within atmospheric and climate research. Making the relevant knowledge transfer pathways and processes transparent is urgently needed to enable systematic determination of the actions required to maximally utilize the existing knowledge, and to ensure effective implementation of new results that may help to narrow down the uncertainty associated with aerosols in climate projections. Improved understanding of the role of aerosols in the climate system will result in enhanced credibility of ESMs and hence also tighter constraints for policies aiming for simultaneous climate neutrality and zero pollution targets.</p>

scholarly journals Lifecycle of light-absorbing carbonaceous aerosols in the atmosphere

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Dantong Liu ◽  
Cenlin He ◽  
Joshua P. Schwarz ◽  
Xuan Wang
Keyword(s):  
Optical Properties ◽  
Radiative Forcing ◽  
Water Solubility ◽  
Model Performance ◽  
Global Scale ◽  
Climate Impacts ◽  
Carbonaceous Aerosols ◽  
Earth System ◽  
The Earth ◽  
Improved Model

Abstract Light-absorbing carbonaceous aerosols (LACs), including black carbon and light-absorbing organic carbon (brown carbon, BrC), have an important role in the Earth system via heating the atmosphere, dimming the surface, modifying the dynamics, reducing snow/ice albedo, and exerting positive radiative forcing. The lifecycle of LACs, from emission to atmospheric evolution further to deposition, is key to their overall climate impacts and uncertainties in determining their hygroscopic and optical properties, atmospheric burden, interactions with clouds, and deposition on the snowpack. At present, direct observations constraining some key processes during the lifecycle of LACs (e.g., interactions between LACs and hydrometeors) are rather limited. Large inconsistencies between directly measured LAC properties and those used for model evaluations also exist. Modern models are starting to incorporate detailed aerosol microphysics to evaluate transformation rates of water solubility, chemical composition, optical properties, and phases of LACs, which have shown improved model performance. However, process-level understanding and modeling are still poor particularly for BrC, and yet to be sufficiently assessed due to lack of global-scale direct measurements. Appropriate treatments of size- and composition-resolved processes that influence both LAC microphysics and aerosol–cloud interactions are expected to advance the quantification of aerosol light absorption and climate impacts in the Earth system. This review summarizes recent advances and up-to-date knowledge on key processes during the lifecycle of LACs, highlighting the essential issues where measurements and modeling need improvement.

Climate and composition impacts of a net-zero anthropogenic methane future using an emissions-driven chemistry-climate model

2021 ◽  
Author(s):  
Zosia Staniaszek ◽  
Paul T. Griffiths ◽  
Gerd A. Folberth ◽  
Fiona M. O'Connor ◽  
Alexander T. Archibald
Keyword(s):  
Tropospheric Ozone ◽  
Radiative Forcing ◽  
Methane Emissions ◽  
Radiation Budget ◽  
Baseline Scenario ◽  
Earth System ◽  
Atmospheric Methane ◽  
The Earth ◽  
Net Zero ◽  
Emissions Scenario

<div> <p>Methane (CH<sub>4</sub>), the second most important greenhouse gas in terms of radiative forcing, is on the rise; but there are extensive opportunities for mitigation with existing technologies. Anthropogenic emissions account for around 60% of the global methane source, and the recent atmospheric methane growth rate puts us on a trajectory comparable to the most extreme future methane scenarios in the sixth Coupled Model Intercomparison Project (CMIP6). </p> </div><div> <p>We use a new methane emissions-driven configuration of the UK Earth System Model (UKESM1) to explore the role of anthropogenic methane in the earth system. The full methane cycle is represented, including surface deposition, chemistry and interactive wetland emissions. As a baseline scenario we used Shared Socioeconomic Pathway 3-7.0 (SSP3-7.0) – the highest methane emissions scenario in CMIP6. In an idealised experiment, all anthropogenic methane emissions were instantaneously stopped from 2015 onwards in a coupled atmosphere-ocean simulation running from 2015-2050, to make a net-zero anthropogenic methane emissions scenario.  </p> </div><div> <p>Within a decade, significant changes can be seen in atmospheric composition and climate, compared to SSP3-7.0. The atmospheric methane burden declines to below pre-industrial levels within 12 years, and by the late 2030s reaches a constant level around 44% below that of the present day (2015). The tropospheric ozone burden and surface mean ozone concentrations decreased by 12% and 15% respectively by 2050 – key in terms of limiting global warming as well as improving air quality and human health. </p> </div><div> <p>By 2050 the net-zero anthropogenic methane scenario results in a global mean surface temperature (GMST) 1˚C lower than the baseline, a significant value in the context of climate goals such as the Paris Agreement. Through decomposition of the radiation budget, the change in climate can be directly attributed to the reduction in methane and indirectly to the resulting changes in ozone, clouds and ozone precursors such as CO. In addition, the changes in climate result in impacts on the interactive wetland emissions via changes in temperature and wetland extent, highlighting the coupled nature of methane in the earth system. </p> </div><div> <p>Cessation of anthropogenic methane emissions has profound impacts on near-term warming and on tropospheric ozone, but ultimately cannot single-handedly achieve the necessary reductions for meeting Paris goals. </p> </div>

Rapid, Refined, and Robust Method for Expression, Purification, and Characterization of Recombinant Human Amyloid-beta M1-42

2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra
Keyword(s):  
Amyloid Beta ◽  
Western Blots ◽  
Force Microscopy ◽  
E Coli ◽  
Atomic Force ◽  
Set Up ◽  
Short Time

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.

Isolation and characterization of oleochemical compounds from watermelon seed

2020 ◽  
Vol 10 (4) ◽  
pp. 79-82
Author(s):  
Madhubhushan M ◽  
Seshaiah S ◽  
Chandrudu J ◽  
Sagar R ◽  
Akila CR
Keyword(s):  
Cutting Tool ◽  
Citrullus Lanatus ◽  
Fatty Esters ◽  
Mineral Oils ◽  
Light Yellow ◽  
Isolation And Characterization ◽  
The Common ◽  
Set Up ◽  
Natural Gradation

The common watermelon item (Citrullus lanatus) seeds were gained from castoffs verdant nourishments for use by decorating, sun ventilation and pulverizing. Light yellow-toned oil was gotten by dissolvable withdrawal using oil atmosphere and the going with traits were gotten using oil ether: pH, refractive rundown, thickness, dissolvable miscibility, coagulating temperature, fire nature, express gravity, streak point and warmth of consuming. With a shallow level of unsaturation, stepped level of smoothness, and proximity of raised degree of the sensible proportion of free unsaturated fats. The low assessment of the solidifying temperature of the oil offered a hint that the oil can be managed in various areas paying little heed to the qualification in temperature. The following level of linoleic destructive of the oil offers a hint of natural gradation of solidarity. Fatty esters are increasing expanding significance as a biodegradable swap for mineral oils. In some request regions, for example, cutting tool oil, gearbox, pressure-driven oils, and greases for raw petroleum creation, the oleochemical items are set up. Nonetheless, certain particular wellsprings of fatty esters are hitherto to be abused for this comparative reason. This exploration subsequently tests into one of the less used wellsprings of fatty esters in watermelon. The oil from the kernels demonstrations a top-notch yield presents significant utilitarian gatherings for change and thus was utilized to set up an assortment of oleochemicals which demonstrated excellence materials in contrast with the routinely utilized oils feed frameworks for oleochemicals after portrayal. The photopolymers acquired indicated piercing vinyl protons for consistent polymerize.

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