scholarly journals Validation of water vapour profiles from the Atmospheric Chemistry Experiment (ACE)

2008 ◽  
Vol 8 (2) ◽  
pp. 4499-4559 ◽  
Author(s):  
M. R. Carleer ◽  
C. D. Boone ◽  
K. A. Walker ◽  
P. F. Bernath ◽  
K. Strong ◽  
...  
Keyword(s):  
Water Vapour ◽  
Atmospheric Chemistry ◽  
Near Infrared ◽  
Mixing Ratio ◽  
Solar Occultation ◽  
Key Species ◽  
Uv Visible ◽  
Ground Based Lidar ◽  
Chemistry Experiment ◽  
Better Than

Abstract. The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Water vapour (H2O), one of the most important molecules for climate and atmospheric chemistry, is one of the key species provided by the two principal instruments, the infrared Fourier Transform Spectrometer (ACE-FTS) and the MAESTRO UV-Visible spectrometer (ACE-MAESTRO). The first instrument performs measurements on several lines in the 1362–2137 cm−1 range, from which vertically resolved H2O concentration profiles are retrieved, from 7 to 90 km altitude. ACE-MAESTRO measures profiles using the water absorption band in the near infrared part of the spectrum at 926.0–969.7 nm. This paper presents a comprehensive validation of the ACE-FTS profiles. We have compared the H2O volume mixing ratio profiles with space-borne (SAGE II, HALOE, POAM III, MIPAS, SMR) observations and measurements from balloon-borne frostpoint hygrometers and a ground based lidar. We show that the ACE-FTS measurements provide H2O profiles with small retrieval uncertainties in the stratosphere (better than 5% from 15 to 70 km, gradually increasing above). The situation is unclear in the upper troposphere, due mainly to the high variability of the water vapour volume mixing ratio in this region. A new water vapour data product from the ACE-MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) is also presented and initial comparisons with ACE-FTS are discussed.

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.

scholarly journals ACE-FTS observations of acetonitrile in the lower stratosphere

2013 ◽  
Vol 13 (15) ◽  
pp. 7405-7413 ◽  
Author(s):  
J. J. Harrison ◽  
P. F. Bernath
Keyword(s):  
Remote Sensing ◽  
Atmospheric Chemistry ◽  
Satellite Remote Sensing ◽  
Lower Stratosphere ◽  
Measurement Noise ◽  
Fourier Transform Spectrometer ◽  
Mixing Ratio ◽  
Solar Occultation ◽  
Retrieval Scheme ◽  
Chemistry Experiment

Abstract. This work reports the first infrared satellite remote-sensing measurements of acetonitrile (CH3CN) in the Earth's atmosphere using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) between 2004 and 2011. The retrieval scheme uses new quantitative laboratory spectroscopic measurements of acetonitrile (Harrison and Bernath, 2012). Although individual ACE-FTS profile measurements are dominated by measurement noise, median profiles in 10° latitude bins show a steady decline in volume mixing ratio from ~150 ppt (parts per trillion) at 11.5 km to < 40 ppt at 25.5–29.5 km. These new measurements agree well with the scant available air- and balloon-borne data in the lower stratosphere. An acetonitrile stratospheric lifetime of 73 ± 20 yr has been determined.

scholarly journals Validation of ACE-FTS v2.2 methane profiles from the upper troposphere to lower mesosphere

2007 ◽  
Vol 7 (6) ◽  
pp. 17975-18014 ◽  
Author(s):  
M. De Mazière ◽  
C. Vigouroux ◽  
P. F. Bernath ◽  
P. Baron ◽  
T. Blumenstock ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
Remote Sensing Data ◽  
Upper Troposphere ◽  
Solar Occultation ◽  
Systematic Uncertainties ◽  
Comparison Results ◽  
Key Species ◽  
Chemistry Experiment

Abstract. The ACE-FTS (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer) solar occultation instrument that was launched onboard the Canadian SCISAT-1 satellite in August 2003 is measuring vertical profiles from the upper troposphere to the lower mesosphere for a large number of atmospheric constituents. Methane is one of the key species. The version v2.2 data of the ACE-FTS CH4 data have been compared to correlative satellite, balloon-borne and ground-based Fourier transform infrared remote sensing data to assess their quality. The comparison results indicate that the accuracy of the data is within 10% in the upper troposphere – lower stratosphere, and within 25% in the middle and higher stratosphere up to the lower mesosphere (<60 km). The observed differences are generally consistent with reported systematic uncertainties. ACE-FTS is also shown to reproduce the variability of methane in the stratosphere and lower mesosphere.

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

2007 ◽  
Vol 7 (5) ◽  
pp. 15277-15340 ◽  
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.

scholarly journals Validation of NO<sub>2</sub> and NO from the Atmospheric Chemistry Experiment (ACE)

2008 ◽  
Vol 8 (1) ◽  
pp. 3027-3142
Author(s):  
T. Kerzenmacher ◽  
M. A. Wolff ◽  
K. Strong ◽  
E. Dupuy ◽  
K. A. Walker ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Near Infrared ◽  
Data Sets ◽  
Solar Occultation ◽  
Box Models ◽  
Infrared Spectrometer ◽  
Near Infrared Spectrometer ◽  
Chemistry Experiment ◽  
Comparison Measurements

Abstract. Vertical profiles of NO2 and NO have been obtained from solar occultation measurements by the Atmospheric Chemistry Experiment (ACE), using an infrared Fourier Transform Spectrometer, ACE-FTS, and an ultraviolet-visible-near-infrared spectrometer, MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation). In this paper, the quality of the ACE-FTS version 2.2 NO2 and NO and the MAESTRO version 1.2 NO2 data are assessed using other solar occultation measurements (HALOE, SAGE II, SAGE III, POAM III, SCIAMACHY), stellar occultation measurements (GOMOS), limb measurements (MIPAS, OSIRIS), nadir measurements (SCIAMACHY), balloon measurements (SPIRALE, SAOZ) and ground-based measurements (UV-VIS, FTIR). Time differences between the comparison measurements were reduced using either a tight coincidence criterion, or where possible, chemical box models. ACE-FTS NO2 and NO and the MAESTRO NO2 are generally consistent with the correlative data. The ACE-FTS NO2 VMRs agree with the satellite data sets to within about 20% between 25 and 40 km, and suggest a negative bias between 23 and 40 km of about \\textminus10%. In comparisons with HALOE, ACE-FTS NO VMRs typically agree to ±8% from 22 to 64 km and to +10% from 93 to 105 km. Partial column comparisons for NO2 show that there is fair agreement between the ACE instruments and the FTIRs, with a mean difference of +7.3% for ACE-FTS and +12.8% for MAESTRO.

scholarly journals Validation of ozone measurements from the Atmospheric Chemistry Experiment (ACE)

2008 ◽  
Vol 8 (1) ◽  
pp. 2513-2656 ◽  
Author(s):  
E. Dupuy ◽  
K. A. Walker ◽  
J. Kar ◽  
C. D. Boone ◽  
C. T. McElroy ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Near Infrared ◽  
Positive Bias ◽  
Solar Occultation ◽  
Ozone Data ◽  
Significant Difference ◽  
Systematic Effects ◽  
Mean Differences ◽  
Chemistry Experiment ◽  
Satellite Instruments

Abstract. This paper presents extensive validation analyses of ozone observations from the Atmospheric Chemistry Experiment (ACE) satellite instruments: the ACE Fourier Transform Spectrometer (ACE-FTS) and the Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (ACE-MAESTRO) instrument. The ACE satellite instruments operate in the mid-infrared and ultraviolet-visible-near-infrared spectral regions using the solar occultation technique. In order to continue the long-standing record of solar occultation measurements from space, a detailed quality assessment is required to evaluate the ACE data and validate their use for scientific purposes. Here we compare the latest ozone data products from ACE-FTS and ACE-MAESTRO with coincident observations from satellite-borne, airborne, balloon-borne and ground-based instruments, by analysing volume mixing ratio profiles and partial column densities. The ACE-FTS version 2.2 Ozone Update product reports more ozone than most correlative measurements from the upper troposphere to the lower mesosphere. At altitude levels from 16 to 44 km, the mean differences range generally between 0 and +10% with a slight but systematic positive bias (typically +5%). At higher altitudes (45–60 km), the ACE-FTS ozone amounts are significantly larger than those of the comparison instruments by up to ~40% (typically +20%). For the ACE-MAESTRO version 1.2 ozone data product, agreement within ±10% (generally better than ±5%) is found between 18 and 40 km for the sunrise and sunset measurements. At higher altitudes (45–55 km), systematic biases of opposite sign are found between the ACE-MAESTRO sunrise and sunset observations. While ozone amounts derived from the ACE-MAESTRO sunrise occultation data are often smaller than the coincident observations (by as much as −10%), the sunset occultation profiles for ACE-MAESTRO show results that are qualitatively similar to ACE-FTS and indicate a large positive bias (+10 to +30%) in this altitude range. In contrast, there is no significant difference in bias found for the ACE-FTS sunrise and sunset measurements. These systematic effects in the ozone profiles retrieved from the measurements of ACE-FTS and ACE-MAESTRO are being investigated. This work shows that the ACE instruments provide reliable, high quality measurements from the tropopause to the upper stratosphere and can be used with confidence in this vertical domain.

scholarly journals First carbon dioxide atmospheric vertical profiles retrieved from space observation using ACE-FTS solar occultation instrument

2010 ◽  
Vol 10 (11) ◽  
pp. 26473-26512
Author(s):  
P. Y. Foucher ◽  
A. Chédin ◽  
R. Armante ◽  
C. Boone ◽  
C. Crevoisier ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Transport ◽  
Vertical Gradient ◽  
Vertical Profiles ◽  
Aircraft Measurements ◽  
Transport Models ◽  
Solar Occultation ◽  
Chemistry Experiment ◽  
Better Than

Abstract. Major limitations of our present knowledge of the global distribution of CO2 in the atmosphere are the uncertainty in atmospheric transport and the sparseness of in situ concentration measurements. Limb viewing spaceborne sounders such as the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) offer a vertical resolution of a few kilometres for profiles, which is much better than currently flying or planned nadir sounding instruments can achieve. After having demonstrated the feasibility of obtaining CO2 vertical profiles in the 5–25 km altitude range with an accuracy of about 2 ppm in a previous study, we present here the results of five years of ACE-FTS observations in terms of monthly mean profiles of CO2 averaged over 10° latitude bands for northern mid-latitudes. These results are compared with in-situ aircraft measurements and with simulations from two different air transport models. Key features of the measured altitude distribution of CO2 are shown to be accurately reproduced by the ACE-FTS retrievals: variation in altitude of the seasonal cycle amplitude and extrema, seasonal change of the vertical gradient, and mean growth rate. We show that small but significant differences from model simulations could result from an over estimation of the model circulation strength during the northern hemisphere spring. Coupled with column measurements from a nadir viewing instrument, it is expected that occultation measurements will bring useful constraints to the surface carbon flux determination.

scholarly journals Calibration and validation of water vapour lidar measurements from Eureka, Nunavut using radiosondes and the Atmospheric Chemistry Experiment fourier transform spectrometer

2012 ◽  
Vol 5 (4) ◽  
pp. 5665-5689 ◽  
Author(s):  
A. Moss ◽  
R. J. Sica ◽  
E. McCullough ◽  
K. Strawbridge ◽  
K. Walker ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Water Vapour ◽  
Atmospheric Chemistry ◽  
Fourier Transform Spectrometer ◽  
Lidar Measurements ◽  
Tropopause Region ◽  
Arctic Atmosphere ◽  
Chemistry Experiment ◽  
Better Than

Abstract. The Canadian Network for the Detection of Atmospheric Change and Environment Canada DIAL lidar located at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nunavut has been upgraded to measure water vapour mixing ratio profiles at 150 m vertical resolution. The system is capable of measuring water vapour in the dry arctic atmosphere up to the tropopause region. Measurements were obtained in the February to March polar sunrise during 2007, 2008 and 2009 as part of the Canadian Arctic ACE Validation Campaign. Before such measurements can be used to address important questions in understanding dynamics and chemistry, the lidar measurements must be calibrated against an independent determination of water vapour. Here, radiosonde measurements of relative humidity have been used to calibrate the lidar measurements. It was found that the calibration varied significantly between each campaign. However, the calibration of the lidar during an individual polar sunrise campaign agrees with the local radiosonde measurements to better than 12% below 6 km altitude. To independently validate the calibration of the lidar derived from the radiosondes, comparisons are made between the calibrated lidar measurements and water vapour measurements from the Atmospheric Chemistry Experiment satellite-borne Fourier Transform Spectrometer. The comparisons between the lidar and satellite for both campaign averages and single overpasses show favourable agreement between the two instruments and help validate the comparison with the radiosondes.

scholarly journals Carbon dioxide atmospheric vertical profiles retrieved from space observation using ACE-FTS solar occultation instrument

2011 ◽  
Vol 11 (6) ◽  
pp. 2455-2470 ◽  
Author(s):  
P. Y. Foucher ◽  
A. Chédin ◽  
R. Armante ◽  
C. Boone ◽  
C. Crevoisier ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Transport ◽  
Vertical Gradient ◽  
Vertical Profiles ◽  
Aircraft Measurements ◽  
Transport Models ◽  
Solar Occultation ◽  
Chemistry Experiment ◽  
Better Than

Abstract. Major limitations of our present knowledge of the global distribution of CO2 in the atmosphere are the uncertainty in atmospheric transport and the sparseness of in situ concentration measurements. Limb viewing spaceborne sounders such as the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) offer a vertical resolution of a few kilometres for profiles, which is much better than currently flying or planned nadir sounding instruments can achieve. After having demonstrated the feasibility of obtaining CO2 vertical profiles in the 5–25 km altitude range with an accuracy of about 2 ppm in a previous study, we present here the results of five years of ACE-FTS observations in terms of monthly mean profiles of CO2 averaged over 10° latitude bands for northern mid-latitudes. These results are compared with in-situ aircraft measurements and with simulations from two different air transport models. Key features of the measured altitude distribution of CO2 are shown to be accurately reproduced by the ACE-FTS retrievals: variation in altitude of the seasonal cycle amplitude and extrema, seasonal change of the vertical gradient, and mean growth rate. We show that small but significant differences from model simulations could result from an over estimation of the model circulation strength during the northern hemisphere spring. Coupled with column measurements from a nadir viewing instrument, it is expected that occultation measurements will bring useful constraints to the surface carbon flux determination.

scholarly journals Validation of 525 nm and 1020 nm aerosol extinction profiles derived from ACE imager data: comparisons with GOMOS, SAGE II, SAGE III, POAM III, and OSIRIS

2007 ◽  
Vol 7 (4) ◽  
pp. 12349-12379
Author(s):  
F. Vanhellemont ◽  
C. Tetard ◽  
A. Bourassa ◽  
M. Fromm ◽  
J. Dodion ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Trace Gas ◽  
Aerosol Extinction ◽  
Optical Extinction ◽  
Upper Troposphere ◽  
Solar Occultation ◽  
Stellar Occultation ◽  
Uv Visible ◽  
Atmospheric Trace Gas ◽  
Chemistry Experiment

Abstract. The Canadian ACE (Atmospheric Chemistry Experiment) mission is dedicated to the retrieval of a large number of atmospheric trace gas species using the solar occultation technique in the infrared and UV/visible spectral domain. However, two additional solar disk imagers (at 525 nm and 1020 nm) were added for a number of reasons, including the retrieval of aerosol and cloud products. In this paper, we present the first validation results for these imager aerosol/cloud optical extinction coefficient profiles, by intercomparison with profiles derived from measurements performed by 3 solar occultation instruments (SAGE II, SAGE III, POAM III), one stellar occultation instrument (GOMOS) and one limb sounder (OSIRIS). The results indicate that the ACE imager profiles are of good quality in the upper troposphere/lower stratosphere, although the aerosol extinction for the visible channel at 525 nm contains a significant negative bias at higher altitudes, while the profiles are systematically too high at 1020 nm. Both problems are probably related to ACE imager instrumental issues.

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