scholarly journals Towards constraints on fossil fuel emissions from total column carbon dioxide

2013 ◽  
Vol 13 (8) ◽  
pp. 4349-4357 ◽  
Author(s):  
G. Keppel-Aleks ◽  
P. O. Wennberg ◽  
C. W. O'Dell ◽  
D. Wunch
Keyword(s):  
General Circulation ◽  
Large Scale ◽  
Fossil Fuel ◽  
Atmospheric General Circulation Model ◽  
Source Region ◽  
Circulation Model ◽  
Policy Tool ◽  
Total Column ◽  
Gosat Satellite ◽  
Fossil Fuel Emissions

Abstract. We assess the large-scale, top-down constraints on regional fossil fuel emissions provided by observations of atmospheric total column CO2, XCO2. Using an atmospheric general circulation model (GCM) with underlying fossil emissions, we determine the influence of regional fossil fuel emissions on global XCO2 fields. We quantify the regional contrasts between source and upwind regions and probe the sensitivity of atmospheric XCO2 to changes in fossil fuel emissions. Regional fossil fuel XCO2 contrasts can exceed 0.7 ppm based on 2007 emission estimates, but have large seasonal variations due to biospheric fluxes. Contamination by clouds reduces the discernible fossil signatures. Nevertheless, our simulations show that atmospheric fossil XCO2 can be tied to its source region and that changes in the regional XCO2 contrasts scale linearly with emissions. We test the GCM results against XCO2 data from the GOSAT satellite. Regional XCO2 contrasts in GOSAT data generally scale with the predictions from the GCM, but the comparison is limited by the moderate precision of and relatively few observations from the satellite. We discuss how this approach may be useful as a policy tool to verify national fossil emissions, as it provides an independent, observational constraint.

scholarly journals Towards constraints on fossil fuel emissions from total column carbon dioxide

2012 ◽  
Vol 12 (11) ◽  
pp. 29887-29913 ◽  
Author(s):  
G. Keppel-Aleks ◽  
P. O. Wennberg ◽  
C. W. O'Dell ◽  
D. Wunch
Keyword(s):  
Carbon Dioxide ◽  
Large Scale ◽  
Fossil Fuel ◽  
Source Region ◽  
Observational Constraint ◽  
Top Down ◽  
Policy Tool ◽  
Total Column ◽  
Gosat Satellite ◽  
Fossil Fuel Emissions

Abstract. We assess the large-scale, top-down constraints on regional fossil fuel emissions provided by observations of atmospheric total column CO2, XCO2. Using an atmospheric GCM with underlying fossil emissions, we determine the influence of regional fossil fuel emissions on global XCO2 fields. We quantify the regional contrasts between source and upwind regions and probe the sensitivity of atmospheric XCO2 to changes in fossil fuel emissions. Regional fossil fuel XCO2 contrasts can exceed 0.7 ppm based on 2007 emission estimates, but have large seasonal variations due to biospheric fluxes. Contamination by clouds reduces the discernible fossil signatures. Nevertheless, our simulations show that atmospheric fossil XCO2 can be tied to its source region and that changes in the regional XCO2 contrasts scale linearly with emissions. We test the GCM results against XCO2 data from the GOSAT satellite. Regional XCO2 contrasts in GOSAT data generally scale with the predictions from the GCM, but the comparison is limited by the moderate precision of and relatively few observations from the satellite. We discuss how this approach may be useful as a policy tool to verify national fossil emissions, as it provides an independent, observational constraint.

scholarly journals Simulation of winter and summer climates with PRL Atmospheric General Circulation Model

MAUSAM ◽  
2021 ◽  
Vol 50 (4) ◽  
pp. 391-400
Author(s):  
BIJU THOMAS ◽  
S.V. KASTURE ◽  
S. V. SATYAN
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Large Scale ◽  
Atmospheric General Circulation Model ◽  
Initial Conditions ◽  
Circulation Model ◽  
Horizontal Resolution ◽  
Hemispheric Differences ◽  
Physical Research Laboratory ◽  
Atmospheric General Circulation

A global, spectral Atmospheric General Circulation Model (AGCM) has been developed indigenously at Physical Research Laboratory (PRL) for climate studies. The model has six a levels in the vertical and has horizontal resolution of 21 waves with rhomboidal truncation. The model includes smooth topography, planetary boundary layer, deep convection, large scale condensation, interactive hydrology, radiation with interactive clouds and diurnal cycle. Sea surface temperature and sea ice values were fixed based on climatological data for different calender months.   The model was integrated for six years starting with an isothermal atmosphere (2400K), zero winds initial conditions and forcing from incoming solar radiation. After one year the model stabilizes. The seasonal averages of various fields of the last five years are discussed in this paper. It is found that the model reproduces reasonably well the seasonal features of atmospheric circulation, seasonal variability and hemispheric differences.

scholarly journals Sources of variations in total column carbon dioxide

2010 ◽  
Vol 10 (12) ◽  
pp. 30569-30611 ◽  
Author(s):  
G. Keppel-Aleks ◽  
P. O. Wennberg ◽  
T. Schneider
Keyword(s):  
Carbon Dioxide ◽  
General Circulation ◽  
Large Scale ◽  
Flux Distribution ◽  
Circulation Model ◽  
Surface Fluxes ◽  
Analysis Framework ◽  
Meridional Gradient ◽  
The North ◽  
Total Column

Abstract. Observations of gradients in the total CO2 column, ‹CO2› are expected to provide improved constraints on surface fluxes of CO2. Here we use a general circulation model with a variety of prescribed carbon fluxes to investigate how variations in ‹CO2› arise. On diurnal scales, variations are small and are forced by both local fluxes and advection. On seasonal scales, gradients are set by the north-south flux distribution. On synoptic scales, variations arise due to large-scale eddy-driven disturbances of the meridional gradient. In this case, because variations in ‹CO2› are tied to synoptic activity, significant correlations exist between ‹CO2› and dynamical tracers. We illustrate how such correlations can be used to describe the north-south gradients of ‹CO2› and the underlying fluxes on continental scales. These simulations suggest a novel analysis framework for using column observations in carbon cycle science.

scholarly journals Technical Note: Latitude-time variations of atmospheric column-average dry air mole fractions of CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O

2012 ◽  
Vol 12 (16) ◽  
pp. 7767-7777 ◽  
Author(s):  
R. Saito ◽  
P. K. Patra ◽  
N. Deutscher ◽  
D. Wunch ◽  
K. Ishijima ◽  
...  
Keyword(s):  
General Circulation ◽  
Fossil Fuel ◽  
Transport Model ◽  
Circulation Model ◽  
Technical Note ◽  
Transport Processes ◽  
Total Carbon ◽  
Poor Correlation ◽  
Model Estimate ◽  
Total Column

Abstract. We present a comparison of an atmospheric general circulation model (AGCM)-based chemistry-transport model (ACTM) simulation with total column measurements of CO2, CH4 and N2O from the Total Carbon Column Observing Network (TCCON). The model is able to capture observed trends, seasonal cycles and inter hemispheric gradients at most sampled locations for all three species. The model-observation agreements are best for CO2, because the simulation uses fossil fuel inventories and an inverse model estimate of non-fossil fuel fluxes. The ACTM captures much of the observed seasonal variability in CO2 and N2O total columns (~81 % variance, R>0.9 between ACTM and TCCON for 19 out of 22 cases). These results suggest that the transport processes in troposphere and stratosphere are well represented in ACTM. Thus the poor correlation between simulated and observed CH4 total columns, particularly at tropical and extra-tropical sites, have been attributed to the uncertainties in surface emissions and loss by hydroxyl radicals. While the upward-looking total column measurements of CO2 contains surface flux signals at various spatial and temporal scales, the N2O measurements are strongly affected by the concentration variations in the upper troposphere and stratosphere.

scholarly journals Sources of variations in total column carbon dioxide

2011 ◽  
Vol 11 (8) ◽  
pp. 3581-3593 ◽  
Author(s):  
G. Keppel-Aleks ◽  
P. O. Wennberg ◽  
T. Schneider
Keyword(s):  
Carbon Dioxide ◽  
General Circulation ◽  
Large Scale ◽  
Flux Distribution ◽  
Circulation Model ◽  
Surface Fluxes ◽  
Analysis Framework ◽  
Meridional Gradient ◽  
The North ◽  
Total Column

Abstract. Observations of gradients in the total CO2 column, 〈CO2〉, are expected to provide improved constraints on surface fluxes of CO2. Here we use a general circulation model with a variety of prescribed carbon fluxes to investigate how variations in 〈CO2〉 arise. On diurnal scales, variations are small and are forced by both local fluxes and advection. On seasonal scales, gradients are set by the north-south flux distribution. On synoptic scales, variations arise due to large-scale eddy-driven disturbances of the meridional gradient. In this case, because variations in 〈CO2〉 are tied to synoptic activity, significant correlations exist between 〈CO2〉 and dynamical tracers. We illustrate how such correlations can be used to describe the north-south gradients of 〈CO2〉 and the underlying fluxes on continental scales. These simulations suggest a novel analysis framework for using column observations in carbon cycle science.

Different Climatological Characteristics, Inner-Core Structures, and Intensification Processes of Simulated Intense Tropical Cyclones between 20-km Global and 5-km Regional Models

2017 ◽  
Vol 30 (5) ◽  
pp. 1583-1603 ◽  
Author(s):  
Sachie Kanada ◽  
Akiyoshi Wada
Keyword(s):  
Tropical Cyclones ◽  
General Circulation ◽  
Large Scale ◽  
Atmospheric General Circulation Model ◽  
Inner Core ◽  
Circulation Model ◽  
Maximum Intensity ◽  
Rapid Intensification ◽  
Nonhydrostatic Model ◽  
Before And After

Abstract Climatological characteristics of simulated intense tropical cyclones (TCs) in the western North Pacific were explored with a 20-km-mesh atmospheric general circulation model (AGCM20) and a 5-km-mesh regional atmospheric nonhydrostatic model (ANHM5). From the AGCM20 climate runs, 34 intense TCs with a minimum central pressure (MCP) less than or equal to 900 hPa were sampled. Downscaling experiments were conducted with the ANHM5 for each intense TC simulated by the AGCM20. Only 23 developed into TCs with MCP ≤ 900 hPa. Most of the best-track TCs with an MCP ≤ 900 hPa underwent rapid intensification (RI) and attained maximum intensities south of 25°N. The AGCM20 simulated a similar number of intense TCs as the best-track datasets. However, the intense AGCM20 TCs tended to intensify longer and more gradually; only half of them underwent RI. The prolonged gradual intensification resulted in significant northward shifts of the location of maximum intensity compared with the location derived from two best-track datasets. The inner-core structure of AGCM20 TCs exhibited weak and shallow eyewall updrafts with maxima below an altitude of 6 km, while downscaling experiments revealed that most of the intense ANHM5 TCs underwent RI with deep and intense eyewall updrafts and attained their maximum intensity at lower latitudes. The altitudes of updraft maxima simulated by the AGCM20 descended rapidly during the phase of greatest intensification as midlevel warming markedly developed. The change in major processes responsible for precipitation in AGCM20 TCs before and after maximum intensification suggests close relationships between the large-scale cloud scheme and midlevel warming and prolonged gradual intensification.

scholarly journals Latitude-time variations of atmospheric column-average dry air mole fractions of CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O

2012 ◽  
Vol 12 (2) ◽  
pp. 5679-5704 ◽  
Author(s):  
R. Saito ◽  
P. K. Patra ◽  
N. Deutscher ◽  
D. Wunch ◽  
K. Ishijima ◽  
...  
Keyword(s):  
General Circulation ◽  
Fossil Fuel ◽  
Transport Model ◽  
Circulation Model ◽  
Transport Processes ◽  
Total Carbon ◽  
Poor Correlation ◽  
Model Estimate ◽  
Spatial And Temporal Scales ◽  
Total Column

Abstract. We present a comparison of an atmospheric general circulation model (AGCM)-based chemistry-transport model (ACTM) simulation with total column measurements of CO2, CH4 and N2O from the Total Carbon Column Observing Network (TCCON). The model is able to capture observed trends, seasonal cycles and inter hemispheric gradients at most sampled locations for all three species. The model-observation agreements are best for CO2, because the simulation uses fossil fuel inventories and an inverse model estimate of non-fossil fuel fluxes. The ACTM captures much of the observed seasonal variability in CO2 and N2O total columns (~81% variance, R>0. 9 between ACTM and TCCON for 19 out of 22 cases). These results suggest that the transport processes in troposphere and stratosphere are well represented in ACTM. Thus the poor correlation between simulated and observed CH4 total columns, particularly at tropical and extra-tropical sites,have been attributed to the uncertainties in surface emissions and loss by hydroxyl radicals. While the upward-looking total column measurements of CO2 contains surface flux signals at various spatial and temporal scales, the N2O measurements are strongly affected by the concentration variations in the upper troposphere and stratosphere.

PALAEO-RA: Combining an intermediate-size AGCM ensemble with historical observations and proxies to create a new dataset of the past 600 years of climate history

2020 ◽  
Author(s):  
Stefan Brönnimann ◽  
Ralf Hand ◽  
Jörg Franke ◽  
Andrey Martynov
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Large Scale ◽  
Atmospheric General Circulation Model ◽  
Historical Data ◽  
Ring Width ◽  
Circulation Model ◽  
Climate History ◽  
The Past ◽  
Atmospheric General Circulation

&lt;p&gt;The recently started PALAEO-RA project aims at creating a new global monthly 3-dimensional reanalysis dataset of the past 600 years' climate. Large spatial and temporal gaps in the available historical data on these time scale make the climate history being an under-determined problem when using observations only. In PALAEO-RA we will addionally use information from an ensemble of simulations with an atmospheric general circulation model (AGCM). The model offers additional physical constraints. The model reproduces teleconnection patterns and reflects typical large-scale modes of variability to set the historical data into a physically consistent regional to global context.&lt;/p&gt;&lt;p&gt;In brief, the method that we plan to use consists of two steps: First, we are currently producing an &amp;#160;ensemble of historical simulations with the atmospheric general circulation model ECHAM6. Once finished, it will have a size of ca. 30 members, covering the period fom 1420 to present. The ensemble is supposed to reflect the range of realistic climate states under prescribed historical radiative forcings (based on the PMIP4 setup) and ocean boundary conditions (HadISST.2 &amp; SST reconstructions by Samakinwa et al., see abstract EGU2020-8744).&lt;/p&gt;&lt;p&gt;Secondly, we will apply Ensemble Kalman Fitting, a technique for the offline assimilation of historical observations (instrumental observations, documentary data, tree ring width and other proxies), basing on the assumption that the occurrence of a distinct observation has a different probability depending on the meso- and large-scale circulation patterns of the atmosphere.&lt;/p&gt;&lt;p&gt;Our poster will give a brief overview on the project with a focus on introducing the AGCM ensemble, also to allow for discussions on further applications of the latter.&lt;/p&gt;

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