scholarly journals ACE-FTS observation of a young biomass burning plume: first reported measurements of C<sub>2</sub>H<sub>4</sub>, C<sub>3</sub>H<sub>6</sub>O, H<sub>2</sub>CO and PAN by infrared occultation from space

2007 ◽  
Vol 7 (3) ◽  
pp. 7907-7932 ◽  
Author(s):  
P.-F. Coheur ◽  
H. Herbin ◽  
C. Clerbaux ◽  
D. Hurtmans ◽  
C. Wespes ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Signal To Noise Ratio ◽  
Source Region ◽  
High Signal ◽  
Upper Troposphere ◽  
Organic Species ◽  
Specific Biomass ◽  
Chemistry Experiment ◽  
Very High

Abstract. In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE–FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they demonstrate that the emissions for this event originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE–FTS spectra over a wide wavenumber range (750–4400 cm−1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

scholarly journals ACE-FTS observation of a young biomass burning plume: first reported measurements of C<sub>2</sub>H<sub>4</sub>, C<sub>3</sub>H<sub>6</sub>O, H<sub>2</sub>CO and PAN by infrared occultation from space

2007 ◽  
Vol 7 (20) ◽  
pp. 5437-5446 ◽  
Author(s):  
P.-F. Coheur ◽  
H. Herbin ◽  
C. Clerbaux ◽  
D. Hurtmans ◽  
C. Wespes ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Signal To Noise Ratio ◽  
Source Region ◽  
High Signal ◽  
Upper Troposphere ◽  
Organic Species ◽  
Specific Biomass ◽  
Chemistry Experiment ◽  
Very High

Abstract. In the course of our study of the upper tropospheric composition with the infrared Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE–FTS), we found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere are performed for this period and they suggest that the emissions for this event likely originated from a nearby forest fire, after which the plume was transported from the source region to the upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE–FTS spectra over a wide wavenumber range (750–4400 cm−1), we present in-depth analyses of the chemical composition of this plume in the middle and upper troposphere, focusing on the measurements of weakly absorbing pollutants. For this specific biomass burning event, we report simultaneous observations of an unprecedented number of organic species. Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) and CH3COO2NO2 (peroxyacetylnitrate, abbreviated as PAN) are the first reported detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the emitted species, we discuss the photochemical age of the plume and also report, whenever possible, the enhancement ratios relative to CO.

scholarly journals Observations of peroxyacetyl nitrate (PAN) in the upper troposphere by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS)

2013 ◽  
Vol 13 (1) ◽  
pp. 1575-1607 ◽  
Author(s):  
K. A. Tereszchuk ◽  
D. P. Moore ◽  
J. J. Harrison ◽  
C. D. Boone ◽  
M. Park ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Fourier Transform Spectrometer ◽  
Data Set ◽  
Upper Troposphere ◽  
Volatile Organic ◽  
The Impact ◽  
Chemistry Experiment

Abstract. Peroxyacetyl nitrate (CH3CO·O2NO2, abbreviated as PAN) is a trace molecular species present in the troposphere and lower stratosphere due primarily to pollution from fuel combustion and the pyrogenic outflows from biomass burning. In the lower troposphere, PAN has a relatively short life-time and is principally destroyed within a few hours through thermolysis, but it can act as a reservoir and carrier of NOx in the colder temperatures of the upper troposphere where UV photolysis becomes the dominant loss mechanism. Pyroconvective updrafts from large biomass burning events can inject PAN into the upper troposphere and lower stratosphere (UTLS), providing a means for the long-range transport of NOx. Given the extended lifetimes at these higher altitudes, PAN is readily detectable via satellite remote sensing. A new PAN data product is now available for the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) Version 3.0 data set. We report measurements of PAN in Boreal biomass burning plumes recorded during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS) campaign. The retrieval method employed and errors analysis are described in full detail. The retrieved volume mixing ratio (VMR) profiles are compared to coincident measurements made by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on the European Space Agency (ESA) ENVIronmental SATellite (ENVISAT). Three ACE-FTS occultations containing measurements of Boreal biomass burning outflows, recorded during BORTAS, were identified as having coincident measurements with MIPAS. In each case, the MIPAS measurements demonstrated good agreement with the ACE-FTS VMR profiles for PAN. The ACE-FTS PAN data set is used to obtain zonal mean distributions of seasonal averages from ~5 to 20 km. A strong seasonality is clearly observed for PAN concentrations in the global UTLS. Since the principal source of PAN in the UTLS is due to lofted biomass burning emissions from the pyroconvective updrafts created by large fires, the observed seasonality in enhanced PAN coincides with fire activity in different geographical regions throughout the year. This work is part of an in-depth investigation that is being conducted in an effort to study the aging and chemical evolution of biomass burning emissions in the UTLS by remote, space-borne measurements made by ACE-FTS to further our understanding of the impact of pyrogenic emissions on atmospheric chemistry. Included in this study will be the addition of new, pyrogenic, volatile organic hydrocarbons (VOCs) and oxygenated volatile organic compounds (OVOCs) to expand upon the already extensive suite of molecules retrieved by ACE-FTS to aid in elucidating biomass burning plume chemistry in the free troposphere.

scholarly journals Observations of peroxyacetyl nitrate (PAN) in the upper troposphere by the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS)

2013 ◽  
Vol 13 (11) ◽  
pp. 5601-5613 ◽  
Author(s):  
K. A. Tereszchuk ◽  
D. P. Moore ◽  
J. J. Harrison ◽  
C. D. Boone ◽  
M. Park ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Biomass Burning ◽  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Full Detail ◽  
Fourier Transform Spectrometer ◽  
Peroxyacetyl Nitrate ◽  
Data Set ◽  
Upper Troposphere ◽  
Chemistry Experiment

Abstract. Peroxyacetyl nitrate (CH3CO·O2NO2, abbreviated as PAN) is a trace molecular species present in the troposphere and lower stratosphere due primarily to pollution from fuel combustion and the pyrogenic outflows from biomass burning. In the lower troposphere, PAN has a relatively short lifetime and is principally destroyed within a few hours through thermolysis, but it can act as a reservoir and carrier of NOx in the colder temperatures of the upper troposphere, where UV photolysis becomes the dominant loss mechanism. Pyroconvective updrafts from large biomass burning events can inject PAN into the upper troposphere and lower stratosphere (UTLS), providing a means for the long-range transport of NOx. Given the extended lifetimes at these higher altitudes, PAN is readily detectable via satellite remote sensing. A new PAN data product is now available for the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) version 3.0 data set. We report observations of PAN in boreal biomass burning plumes recorded during the BORTAS (quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites) campaign (12 July to 3 August 2011). The retrieval method employed by incorporating laboratory-recorded absorption cross sections into version 3.0 of the ACE-FTS forward model and retrieval software is described in full detail. The estimated detection limit for ACE-FTS PAN is 5 pptv, and the total systematic error contribution to the ACE-FTS PAN retrieval is ~ 16%. The retrieved volume mixing ratio (VMR) profiles are compared to coincident measurements made by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument on the European Space Agency (ESA) Environmental Satellite (ENVISAT). The MIPAS measurements demonstrated good agreement with the ACE-FTS VMR profiles for PAN, where the measured VMR values are well within the associated measurement errors for both instruments and comparative measurements differ no more than 70 pptv. The ACE-FTS PAN data set is used to obtain zonal mean distributions of seasonal averages from ~ 5–20 km. A strong seasonality is clearly observed for PAN concentrations in the global UTLS. Since the principal source of PAN in the UTLS is due to lofted biomass burning emissions from the pyroconvective updrafts created by large fires, the observed seasonality in enhanced PAN coincides with fire activity in different geographical regions throughout the year.

scholarly journals The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

2008 ◽  
Vol 8 (3) ◽  
pp. 505-522 ◽  
Author(s):  
G. L. Manney ◽  
W. H. Daffer ◽  
K. B. Strawbridge ◽  
K. A. Walker ◽  
C. D. Boone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
High Arctic ◽  
Trace Gas ◽  
Satellite Measurements ◽  
Broadband Emission ◽  
Gas Measurements ◽  
Chemistry Experiment ◽  
Very High ◽  
Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

scholarly journals CO measurements from the ACE-FTS satellite instrument: data analysis and validation using ground-based, airborne and spaceborne observations

2008 ◽  
Vol 8 (9) ◽  
pp. 2569-2594 ◽  
Author(s):  
C. Clerbaux ◽  
M. George ◽  
S. Turquety ◽  
K. A. Walker ◽  
B. Barret ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Atmospheric Chemistry ◽  
Measurement Data ◽  
Upper Troposphere ◽  
Remote Sensors ◽  
Key Species ◽  
Vibrational Bands ◽  
Good Tracer ◽  
Chemistry Experiment ◽  
Better Than

Abstract. The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), a good tracer of pollution plumes and atmospheric dynamics, is one of the key species provided by the primary instrument, the ACE-Fourier Transform Spectrometer (ACE-FTS). This instrument performs measurements in both the CO 1-0 and 2-0 ro-vibrational bands, from which vertically resolved CO concentration profiles are retrieved, from the mid-troposphere to the thermosphere. This paper presents an updated description of the ACE-FTS version 2.2 CO data product, along with a comprehensive validation of these profiles using available observations (February 2004 to December 2006). We have compared the CO partial columns with ground-based measurements using Fourier transform infrared spectroscopy and millimeter wave radiometry, and the volume mixing ratio profiles with airborne (both high-altitude balloon flight and airplane) observations. CO satellite observations provided by nadir-looking instruments (MOPITT and TES) as well as limb-viewing remote sensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS CO products. We show that the ACE-FTS measurements provide CO profiles with small retrieval errors (better than 5% from the upper troposphere to 40 km, and better than 10% above). These observations agree well with the correlative measurements, considering the rather loose coincidence criteria in some cases. Based on the validation exercise we assess the following uncertainties to the ACE-FTS measurement data: better than 15% in the upper troposphere (8–12 km), than 30% in the lower stratosphere (12–30 km), and than 25% from 30 to 100 km.

Effects of Very High Neutron Fluence Irradiation on p+n Junction 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 917-920 ◽  
Author(s):  
Francesco Moscatelli ◽  
Andrea Scorzoni ◽  
Antonella Poggi ◽  
Mara Passini ◽  
Giulio Pizzocchero ◽  
...  
Keyword(s):  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Reverse Bias ◽  
Neutron Fluence ◽  
Signal To Noise Ratio ◽  
Reverse Current ◽  
Low Noise ◽  
High Signal ◽  
Very High

In this work we analyzed the radiation hardness of SiC p+n diodes after very high 1 MeV neutron fluence. The diode structure is based on a p+ emitter ion implanted in n-type epilayer with thickness equal to 5 %m and donor doping ND = 3×1015 cm-3. Before irradiation, the average leakage current density at 100 V reverse bias was of the order of 3 nA/cm2. These devices were irradiated at four different fluence values, logarithmically distributed in the range 1014-1016 (1 MeV) neutrons/cm2. After irradiation the epilayer material became more resistive, as indicated by the reduction of the forward and reverse current density at a given voltage. In particular, after a neutron fluence of 1×1014 n/cm2 the epilayer active doping concentration decreased to 1.5×1015 cm-3. After irradiation at 1016 n/cm2, i.e. the highest fluence value, the average leakage current density at 100 V reverse bias decreased to values of the order of 0.1 nA/cm2. This very low noise even after very high fluence is very important to obtain a high signal to noise ratio even at room temperature.

A recent slowdown in the decline of CFC-11 concentrations in the upper troposphere

2020 ◽  
Author(s):  
Patrick Sheese ◽  
Kaley Walker ◽  
Chris Boone ◽  
Laura Saunders ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
Recent Change ◽  
Fourier Transform Spectrometer ◽  
Chemical Transport Model ◽  
Surface Level ◽  
Upper Troposphere ◽  
The Past ◽  
Ozone Depleting Substances ◽  
Chemistry Experiment

&lt;p&gt;Since 2004, the Atmospheric Chemistry Experiment &amp;#8211; Fourier Transform Spectrometer (ACE-FTS) instrument has been measuring concentrations of chlorofluorocarbons (CFCs) in the stratosphere and upper troposphere and is currently the only satellite instrument that measures vertically resolved profiles of CFC&amp;#8209;11. Since CFCs are major ozone depleting substances, monitoring their atmospheric abundances is critical for understanding ozone layer recovery. Recent studies based solely on surface-level measurements have shown strong evidence for new CFC&amp;#8209;11 production, leading to an increase in CFC&amp;#8209;11 emissions over the past decade. In this study, the TOMCAT/SLIMCAT 3-D chemical transport model is used in order to bridge the altitude/geolocation gap between ACE-FTS measurements in the UTLS and surface level measurements. Trends in two different time periods over the ACE-FTS mission, 2004-2012 and 2013-2018, are examined to determine if the recent change in surface level CFC-11 trends is influencing UTLS concentrations. The ACE-FTS measurements show that, below ~10 km, the rate of decrease of global CFC-11 concentrations was slower during 2013-2018 (-1.2 pptv/year) than during 2004-2012 (&amp;#8209;2.0 pptv/year). Similar trends are observed in the model data for the same spatial/temporal regions.&lt;/p&gt;

scholarly journals Chemical isolation in the Asian monsoon anticyclone observed in Atmospheric Chemistry Experiment (ACE-FTS) data

2008 ◽  
Vol 8 (3) ◽  
pp. 757-764 ◽  
Author(s):  
M. Park ◽  
W. J. Randel ◽  
L. K. Emmons ◽  
P. F. Bernath ◽  
K. A. Walker ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Asian Monsoon ◽  
Lower Stratosphere ◽  
Chemical Constituents ◽  
Strong Correlations ◽  
Near Surface ◽  
Upper Troposphere ◽  
Relative Age ◽  
Rapid Transport ◽  
Chemistry Experiment

Abstract. Evidence of chemical isolation in the Asian monsoon anticyclone is presented using chemical constituents obtained from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer instrument during summer (June–August) of 2004–2006. Carbon monoxide (CO) shows a broad maximum over the monsoon anticyclone region in the upper troposphere and lower stratosphere (UTLS); these enhanced CO values are associated with air pollution transported upward by convection, and confined by the strong anticyclonic circulation. Profiles inside the anticyclone show enhancement of tropospheric tracers CO, HCN, C2H6, and C2H2 between ~12 to 20 km, with maxima near 13–15 km. Strong correlations are observed among constituents, consistent with sources from near-surface pollution and biomass burning. Stratospheric tracers (O3, HNO3 and HCl) exhibit decreased values inside the anticyclone between ~12–20 km. These observations are further evidence of transport of lower tropospheric air into the UTLS region, and isolation of air within the anticyclone. The relative enhancements of tropospheric species inside the anticyclone are closely related to the photochemical lifetime of the species, with strongest enhancement for shorter lived species. Vertical profiles of the ratio of C2H2/CO (used to measure the relative age of air) suggest relatively rapid transport of fresh emissions up to the tropopause level inside the anticyclone.

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