scholarly journals Atmospheric CO2 levels from 2.7 billion years ago inferred from micrometeorite oxidation

2020 ◽  
Vol 6 (4) ◽  
pp. eaay4644 ◽  
Author(s):  
O. R. Lehmer ◽  
D. C. Catling ◽  
R. Buick ◽  
D. E. Brownlee ◽  
S. Newport
Keyword(s):  
Oxidation State ◽  
Atmospheric Co2 ◽  
Atmospheric Composition ◽  
Atmospheric Conditions ◽  
Early Atmosphere ◽  
Co2 Levels ◽  
Kinetic Oxidation

Earth’s atmospheric composition during the Archean eon of 4 to 2.5 billion years ago has few constraints. However, the geochemistry of recently discovered iron-rich micrometeorites from 2.7 billion–year–old limestones could serve as a proxy for ancient gas concentrations. When micrometeorites entered the atmosphere, they melted and preserved a record of atmospheric interaction. We model the motion, evaporation, and kinetic oxidation by CO2 of micrometeorites entering a CO2-rich atmosphere. We consider a CO2-rich rather than an O2-rich atmosphere, as considered previously, because this better represents likely atmospheric conditions in the anoxic Archean. Our model reproduces the observed oxidation state of micrometeorites at 2.7 Ga for an estimated atmospheric CO2 concentration of >70% by volume. Even if the early atmosphere was thinner than today, the elevated CO2 level indicated by our model result would help resolve how the Late Archean Earth remained warm when the young Sun was ~20% fainter.

scholarly journals GIS-Based Approach to Spatio-Temporal Interpolation of Atmospheric CO2 Concentrations in Limited Monitoring Dataset

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 384
Author(s):  
Yaroslav Bezyk ◽  
Izabela Sówka ◽  
Maciej Górka ◽  
Jan Blachowski
Keyword(s):  
Seasonal Variability ◽  
Sampling Strategy ◽  
Climate Impacts ◽  
Air Pollutant ◽  
Urban Atmosphere ◽  
Atmospheric Co2 ◽  
Spatial Characteristic ◽  
Interpolation Methods ◽  
Co2 Levels ◽  
The City

Understanding the magnitude and distribution of the mixes of the near-ground carbon dioxide (CO2) components spatially (related to the surface characteristics) and temporally (over seasonal timescales) is critical to evaluating present and future climate impacts. Thus, the application of in situ measurement approaches, combined with the spatial interpolation methods, will help to explore variations in source contribution to the total CO2 mixing ratios in the urban atmosphere. This study presents the spatial characteristic and temporal trend of atmospheric CO2 levels observed within the city of Wroclaw, Poland for the July 2017–August 2018 period. The seasonal variability of atmospheric CO2 around the city was directly measured at the selected sites using flask sampling with a Picarro G2201-I Cavity Ring-Down Spectroscopy (CRDS) technique. The current work aimed at determining the accuracy of the interpolation techniques and adjusting the interpolation parameters for estimating the magnitude of CO2 time series/seasonal variability in terms of limited observations during the vegetation and non-vegetation periods. The objective was to evaluate how different interpolation methods will affect the assessment of air pollutant levels in the urban environment and identify the optimal sampling strategy. The study discusses the schemes for optimization of the interpolation results that may be adopted in areas where no observations are available, which is based on the kriging error predictions for an appropriate spatial density of measurement locations. Finally, the interpolation results were extended regarding the average prediction bias by exploring additional experimental configurations and introducing the limitation of the future sampling strategy on the seasonal representation of the CO2 levels in the urban area.

scholarly journals Combining fire radiative power observations with the fire weather index improves the estimation of fire emissions

2017 ◽  
Author(s):  
Francesca Di Giuseppe ◽  
Samuel Rémy ◽  
Florian Pappenberger ◽  
Fredrik Wetterhall
Keyword(s):  
Biomass Burning ◽  
Atmospheric Composition ◽  
Composition Analysis ◽  
Fire Weather ◽  
Atmospheric Conditions ◽  
Weather Index ◽  
Fire Weather Index ◽  
Fire Emissions ◽  
Radiative Power ◽  
Fire Radiative Power

Abstract. The atmospheric composition analysis and forecast for the European Copernicus Atmosphere Monitoring Services (CAMS) relies on biomass burning fire emission estimates from the Global Fire Assimilation System (GFAS). GFAS converts fire radiative power (FRP) observations from MODIS satellites into smoke constituents. Missing observations are filled in using persistence where observed FRP from the previous day are progressed in time until a new observation is recorded. One of the consequences of this assumption is an overestimation of fire duration, which in turn translates into an overestimation of emissions from fires. In this study persistence is replaced by modelled predictions using the Canadian Fire Weather Index (FWI), which describes how atmospheric conditions affect the vegetation moisture content and ultimately fire duration. The skill in predicting emissions from biomass burning is improved with the new technique, which indicates that using an FWI-based model to infer emissions from FRP is better than persistence when observations are not available.

scholarly journals The horizontal resolution of MIPAS

2008 ◽  
Vol 1 (1) ◽  
pp. 103-125 ◽  
Author(s):  
T. von Clarmann ◽  
C. De Clercq ◽  
M. Ridolfi ◽  
M. Höpfner ◽  
J.-C. Lambert
Keyword(s):  
Michelson Interferometer ◽  
Elevation Angle ◽  
Emission Spectra ◽  
Horizontal Resolution ◽  
Atmospheric Composition ◽  
Trace Gas ◽  
Atmospheric Conditions ◽  
Tangent Point ◽  
High Vertical Resolution ◽  
Along Track

Abstract. Limb remote sensing from space provides atmospheric composition measurements at high vertical resolution while the information is smeared in the horizontal domain. The horizontal components of two-dimensional (altitude and along-track coordinate) averaging kernels of a limb retrieval constrained to horizontal homogeneity can be used to estimate the horizontal resolution of limb retrievals. This is useful for comparisons of measured data with modeled data, to construct horizontal observation operators in data assimilation applications or when measurements of different horizontal resolution are intercompared. We present these averaging kernels for retrievals of temperature, H2O, O3, CH4, N2O, HNO3 and NO2 from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) high-resolution limb emission spectra. The horizontal smearing of a MIPAS retrieval in terms of full width at half maximum of the rows of the horizontal averaging kernel matrix varies typically between about 200 and 350 km for most species, altitudes and atmospheric conditions. The range where 95% of the information originates from varies from about 260 to 440 km for these cases. This information spread is smaller than the MIPAS horizontal sampling, i.e. MIPAS data are horizontally undersampled, and the effective horizontal resolution is driven by the sampling rather than the smearing. The point where the majority of the information originates from is displaced from the tangent point towards the satellite by typically less than 10 km for trace gas profiles and about 50 to 100 km for temperature, with a few exceptions for uppermost altitudes. The geolocation of a MIPAS profile is defined as the tangent point of the middle line of sight in a MIPAS limb scan. The majority of the information displacement with respect to this nominal geolocation of the measurement is caused by the satellite movement and the geometrical displacement of the actual tangent point as a function of the elevation angle. In none of the cases investigated, propagation of the horizontal smoothing on the vertical profile shape has been observed.

scholarly journals Evidence for the Postconquest Demographic Collapse of the Americas in Historical CO2 Levels

2006 ◽  
Vol 10 (11) ◽  
pp. 1-14 ◽  
Author(s):  
Franz X. Faust ◽  
Cristóbal Gnecco ◽  
Hermann Mannstein ◽  
Jörg Stamm
Keyword(s):  
Population Dynamics ◽  
Strong Evidence ◽  
Ice Cores ◽  
Causal Chain ◽  
Atmospheric Co2 ◽  
Agricultural Fields ◽  
Native Populations ◽  
Co2 Levels ◽  
European Colonization ◽  
Global Population

Abstract This article promotes the hypothesis that the massive demographic collapse of the native populations of the Americas triggered by the European colonization brought about the abandonment of large expanses of agricultural fields soon recovered by forests, which in due turn fixed atmospheric CO2 in significant quantities. This hypothesis is supported by measurements of atmospheric CO2 levels in ice cores from Law Dome, Antarctica. Changing the focus from paleoclimate to global population dynamics and using the same causal chain, the measured drop in historic atmospheric CO2 levels can also be looked upon as further, strong evidence for the postconquest demographic collapse of the Americas.

Millennial-scale changes in atmospheric CO2 levels linked to the Southern Ocean carbon isotope gradient and dust flux

2013 ◽  
Vol 6 (6) ◽  
pp. 457-461 ◽  
Author(s):  
Martin Ziegler ◽  
Paula Diz ◽  
Ian R. Hall ◽  
Rainer Zahn
Keyword(s):  
Southern Ocean ◽  
Carbon Isotope ◽  
Atmospheric Co2 ◽  
Dust Flux ◽  
Co2 Levels ◽  
Ocean Carbon ◽  
Millennial Scale

Stability of atmospheric CO2 levels across the Triassic/Jurassic boundary

Nature ◽  
2001 ◽  
Vol 411 (6838) ◽  
pp. 675-677 ◽  
Author(s):  
Lawrence H. Tanner ◽  
John F. Hubert ◽  
Brian P. Coffey ◽  
Dennis P. McInerney
Keyword(s):  
Atmospheric Co2 ◽  
Co2 Levels

High dependence of Ordovician ocean surface circulation on atmospheric CO2 levels

2016 ◽  
Vol 458 ◽  
pp. 39-51 ◽  
Author(s):  
Alexandre Pohl ◽  
Elise Nardin ◽  
Thijs R.A. Vandenbroucke ◽  
Yannick Donnadieu
Keyword(s):  
Ocean Surface ◽  
Atmospheric Co2 ◽  
Surface Circulation ◽  
Co2 Levels ◽  
Ocean Surface Circulation
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