scholarly journals Attempt to identify sources of atmospheric methane and carbon dioxide concentrations found in in situ aircraft measurements over Southern Australia

2008 ◽  
Vol 113 (D14) ◽  
Author(s):  
Ryu Saito ◽  
Jörg M. Hacker ◽  
Gen Inoue ◽  
Tatsuya Yokota
Keyword(s):  
Carbon Dioxide ◽  
Aircraft Measurements ◽  
Atmospheric Methane ◽  
Carbon Dioxide Concentrations

A Comparison of In Situ Aircraft Measurements of Carbon Dioxide and Methane to GOSAT Data Measured Over Railroad Valley Playa, Nevada, USA

2014 ◽  
Vol 52 (12) ◽  
pp. 7764-7774 ◽  
Author(s):  
J. M. Tadic ◽  
Max Loewenstein ◽  
Christian Frankenberg ◽  
Andre Butz ◽  
Matthew Roby ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Aircraft Measurements

Novel In-Situ Laser Based Diagnostics for Measurement of Water Vapor and Carbon Dioxide Concentrations in the Gas Distribution Channels of a PEM Fuel Cell

2009 ◽  
Author(s):  
Derek E. Lambe ◽  
Kyle Seleski ◽  
Ranganathan Kumar ◽  
Saptarshi Basu
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Fuel Cell ◽  
Visual Observation ◽  
Test Cell ◽  
Tunable Diode Laser ◽  
Flow Paths ◽  
Laser Absorption ◽  
Carbon Dioxide Concentrations

A novel method has been implemented for measuring the concentration of various gas species (water vapor, carbon dioxide) within fuel cell gas channels and other minichannel applications in a non-invasive manner through the use of tunable diode laser absorption spectroscopy (TDLAS). An optically accessible test cell has been designed to allow for the passage of 1–0.5 millimeter diameter laser beams along 12 mm-12 cm long flow paths, while also allowing for visual observation of the channels in order to detect the formation of liquid water. Concentrations of water vapor and carbon dioxide have been measured in situ within the test cell with a temporal resolution of 0.5 secs and 2.5 secs respectively. The technique is portable to high aspect ratio channels yielding concentration measurements of species over 1 mm long passages with an experimental uncertainty of 5%.

scholarly journals Derivation of tropospheric methane from TCCON CH<sub>4</sub> and HF total column observations

2014 ◽  
Vol 7 (9) ◽  
pp. 2907-2918 ◽  
Author(s):  
K. M. Saad ◽  
D. Wunch ◽  
G. C. Toon ◽  
P. Bernath ◽  
C. Boone ◽  
...  
Keyword(s):  
Surface Fluxes ◽  
Total Carbon ◽  
Strongly Correlated ◽  
Aircraft Measurements ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Stratospheric Dynamics ◽  
The Relationship ◽  
Total Column

Abstract. The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH4). Temporal variability in the total column of CH4 due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local surface fluxes that are critical for understanding CH4 sources and sinks. We reduce the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH4 derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for stratospheric CH4 because it is strongly correlated to CH4 in the stratosphere, has an accurately known tropospheric abundance (of zero), and is measured at most TCCON stations. The stratospheric partial column of CH4 is calculated as a function of the zonal and annual trends in the relationship between CH4 and HF in the stratosphere, which we determine from ACE-FTS satellite data. We also explicitly take into account the CH4 column averaging kernel to estimate the contribution of stratospheric CH4 to the total column. The resulting tropospheric CH4 columns are consistent with in situ aircraft measurements and augment existing observations in the troposphere.

scholarly journals Aircraft measurements of carbon dioxide and methane for the calibration of ground-based high-resolution Fourier Transform Spectrometers and a comparison to GOSAT data measured over Tsukuba and Moshiri

2012 ◽  
Vol 5 (1) ◽  
pp. 1843-1871 ◽  
Author(s):  
T. Tanaka ◽  
Y. Miyamoto ◽  
I. Morino ◽  
T. Machida ◽  
T. Nagahama ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Fourier Transform ◽  
High Resolution ◽  
Aircraft Measurements ◽  
Gaseous Species ◽  
Aircraft Measurement ◽  
Airborne Measurements ◽  
Carbon Dioxide Co2 ◽  
First Time

Abstract. Aircraft measurements of carbon dioxide and methane over Tsukuba (36.05° N, 140.12° E) (February 2010) and Moshiri (44.36° N, 142.26° E) (August 2009) were made to calibrate ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) and to compare with the Greenhouse gases Observing SATellite (GOSAT). The aircraft measurements over Tsukuba in February 2010 were successful in synchronizing with both the g-b FTS and GOSAT for the first time. Airborne in situ and flask sampling instruments were mounted on the aircraft and measurements were carried out between altitudes of 0.5 and 7 km to obtain vertical profiles of carbon dioxide (CO2), methane (CH4), and other gaseous species. By comparing the g-b FTS measurements with the airborne measurements, the column-averaged dry air mole fractions of CO2 (XCO2) and CH4 (XCH4) retrieved from the g-b FTS measurements at Tsukuba were biased low by 0.33 ± 0.11% for XCO2 and 0.69 ± 0.29% for XCH4. The g-b FTS values at the Moshiri were biased low by 1.24% for XCO2 and 2.11% for XCH4. The GOSAT data show biases that are 3.1 ± 1.7% low for XCO2 and 2.5 ± 0.8% low for XCH4 than the aircraft measurement obtained over Tsukuba.

scholarly journals Atmospheric methane removal: a research agenda

2021 ◽  
Vol 379 (2210) ◽  
pp. 20200454 ◽  
Author(s):  
Robert B. Jackson ◽  
Sam Abernethy ◽  
Josep G. Canadell ◽  
Matteo Cargnello ◽  
Steven J. Davis ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Methane Oxidation ◽  
Research Agenda ◽  
The Arctic ◽  
Anthropogenic Emissions ◽  
Atmospheric Methane ◽  
Model Intercomparison ◽  
Intercomparison Project ◽  
Removal Model

Atmospheric methane removal (e.g. in situ methane oxidation to carbon dioxide) may be needed to offset continued methane release and limit the global warming contribution of this potent greenhouse gas. Because mitigating most anthropogenic emissions of methane is uncertain this century, and sudden methane releases from the Arctic or elsewhere cannot be excluded, technologies for methane removal or oxidation may be required. Carbon dioxide removal has an increasingly well-established research agenda and technological foundation. No similar framework exists for methane removal. We believe that a research agenda for negative methane emissions—‘removal' or atmospheric methane oxidation—is needed. We outline some considerations for such an agenda here, including a proposed Methane Removal Model Intercomparison Project (MR-MIP). This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 1)'.

scholarly journals Derivation of tropospheric methane from TCCON CH<sub>4</sub> and HF total column observations

2014 ◽  
Vol 7 (4) ◽  
pp. 3471-3501
Author(s):  
K. M. Saad ◽  
D. Wunch ◽  
G. C. Toon ◽  
P. Bernath ◽  
C. Boone ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Inverse Relationship ◽  
Total Carbon ◽  
Aircraft Measurements ◽  
Atmospheric Methane ◽  
Sources And Sinks ◽  
Stratospheric Dynamics ◽  
The Relationship ◽  
Total Column

Abstract. The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH4). Temporal variability in the total column of CH4 due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local sources and sinks. We remove the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH4 derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for stratospheric CH4 because it resides solely in the stratosphere, has a nearly linear inverse relationship with stratospheric CH4, and is measured at most TCCON stations. The stratospheric partial column of CH4 is calculated as a function of the zonal and annual trends in the relationship between CH4 and HF in the stratosphere, which we determine from ACE-FTS satellite data. We also explicitly take into account the CH4 column averaging kernel to estimate the contribution of stratospheric CH4 to the total column. The resulting tropospheric CH4 columns are consistent with in situ aircraft measurements and augment existing observations in the troposphere.

scholarly journals Aircraft measurements of carbon dioxide and methane for the calibration of ground-based high-resolution Fourier Transform Spectrometers and a comparison to GOSAT data measured over Tsukuba and Moshiri

2012 ◽  
Vol 5 (8) ◽  
pp. 2003-2012 ◽  
Author(s):  
T. Tanaka ◽  
Y. Miyamoto ◽  
I. Morino ◽  
T. Machida ◽  
T. Nagahama ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Fourier Transform ◽  
High Resolution ◽  
Vertical Profiles ◽  
Aircraft Measurements ◽  
Gaseous Species ◽  
Airborne Measurements ◽  
Carbon Dioxide Co2 ◽  
First Time

Abstract. Aircraft measurements of carbon dioxide and methane over Tsukuba (36.05° N, 140.12° E) (February 2010) and Moshiri (44.36° N, 142.26° E) (August 2009) were made to calibrate ground-based high-resolution Fourier Transform Spectrometers (g-b FTSs) and to compare with the Greenhouse gases Observing SATellite (GOSAT). The aircraft measurements over Tsukuba in February 2010 were successful in synchronizing with both the g-b FTS and GOSAT for the first time. Airborne in situ and flask-sampling instruments were mounted on the aircraft, and measurements were carried out between altitudes of 0.5 and 7 km to obtain vertical profiles of carbon dioxide (CO2), methane (CH4), and other gaseous species. By comparing the g-b FTS measurements with the airborne measurements, the column-averaged dry air mole fractions of CO2 (XCO2) and CH4 (XCH4) retrieved from the g-b FTS measurements at Tsukuba were biased low by 0.33 ± 0.11% for XCO2 and 0.69 ± 0.29% for XCH4. The g-b FTS values at Moshiri were biased low by 1.24% for XCO2 and 2.11% for XCH4. The GOSAT data show biases that are 3.1% ± 1.7% lower for XCO2 and 2.5% ± 0.8% lower for XCH4 than the aircraft measurements obtained over Tsukuba.

scholarly journals A framework for comparing remotely sensed and in-situ CO<sub>2</sub> concentrations

2008 ◽  
Vol 8 (9) ◽  
pp. 2555-2568 ◽  
Author(s):  
R. Macatangay ◽  
T. Warneke ◽  
C. Gerbig ◽  
S. Körner ◽  
R. Ahmadov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Transport Model ◽  
Remotely Sensed ◽  
Infrared Spectrometry ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
Global Calibration ◽  
Carbon Dioxide Concentrations ◽  
Made In

Abstract. A framework has been developed that allows validating CO2 column averaged volume mixing ratios (VMRs) retrieved from ground-based solar absorption measurements using Fourier transform infrared spectrometry (FTS) against measurements made in-situ (such as from aircrafts and tall towers). Since in-situ measurements are done frequently and at high accuracy on the global calibration scale, linking this scale with FTS total column retrievals ultimately provides a calibration scale for remote sensing. FTS, tower and aircraft data were analyzed from measurements during the CarboEurope Regional Experiment Strategy (CERES) from May to June 2005 in Biscarrosse, France. Carbon dioxide VMRs from the MetAir Dimona aircraft, the TM3 global transport model and Observations of the Middle Stratosphere (OMS) balloon based experiments were combined and integrated to compare with the FTS measurements. The comparison allows for calibrating the retrieved carbon dioxide VMRs from the FTS. The Stochastic Time Inverted Lagrangian Transport (STILT) model was then utilized to identify differences in surface influence regions or footprints between the FTS and the aircraft CO2 concentrations. Additionally, the STILT model was used to compare carbon dioxide concentrations from a tall tower situated in close proximity to the FTS station. The STILT model was then modified to produce column concentrations of CO2 to facilitate comparison with the FTS data. These comparisons were additionally verified by using the Weather Research and Forecasting – Vegetation Photosynthesis and Respiration Model (WRF-VPRM). The differences between the model-tower and the model-FTS were then used to calculate an effective bias of approximately −2.5 ppm between the FTS and the tower. This bias is attributed to the scaling factor used in the FTS CO2 data, which was to a large extent derived from the aircraft measurements made within a 50 km distance from the FTS station: spatial heterogeneity of carbon dioxide in the coastal area caused a low bias in the FTS calibration. Using STILT for comparing remotely sensed CO2 data with tower measurements of carbon dioxide and quantifying this comparison by means of an effective bias, provided a framework or a "transfer standard" that allowed validating the FTS retrievals versus measurements made in-situ.

scholarly journals Snowfall-albedo feedbacks could have led to deglaciation of snowball Earth starting from mid-latitudes

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Philipp de Vrese ◽  
Tobias Stacke ◽  
Jeremy Caves Rugenstein ◽  
Jason Goodman ◽  
Victor Brovkin
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Climate Models ◽  
Hydrological Cycle ◽  
High Surface ◽  
Dust Deposition ◽  
Carbon Dioxide Concentrations ◽  
Maximum Temperatures ◽  
Carbon Dioxide Levels ◽  
Earth’S Climate

AbstractSimple and complex climate models suggest a hard snowball – a completely ice-covered planet – is one of the steady-states of Earth’s climate. However, a seemingly insurmountable challenge to the hard-snowball hypothesis lies in the difficulty in explaining how the planet could have exited the glaciated state within a realistic range of atmospheric carbon dioxide concentrations. Here, we use simulations with the Earth system model MPI-ESM to demonstrate that terminal deglaciation could have been triggered by high dust deposition fluxes. In these simulations, deglaciation is not initiated in the tropics, where a strong hydrological cycle constantly regenerates fresh snow at the surface, which limits the dust accumulation and snow aging, resulting in a high surface albedo. Instead, comparatively low precipitation rates in the mid-latitudes in combination with high maximum temperatures facilitate lower albedos and snow dynamics that – for extreme dust fluxes – trigger deglaciation even at present-day carbon dioxide levels.

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