Aerosol extinction profiles at 525 nm and 1020 nm derived from ACE imager data: comparisons with GOMOS, SAGE II, SAGE III, POAM III, and OSIRIS

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 first comparison results for these imager aerosol/cloud optical extinction coefficient profiles, with the ones 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 relative differences indicate that ACE profiles are almost always too high at 1020 nm. Both problems are probably related to ACE imager instrumental issues.

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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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-12349-2007 ◽

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-17975-2007 ◽

2007 ◽

Vol 7 (6) ◽

pp. 17975-18014 ◽

Cited By ~ 2

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.

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ACE-FTS version 3.0 data set: validation and data processing update

Annals of Geophysics ◽

10.4401/ag-6339 ◽

2014 ◽

Vol 56 ◽

Author(s):

Claire Waymark ◽

Kaley Walker ◽

Chris D. Boone ◽

Peter F. Bernath

Keyword(s):

Atmospheric Chemistry ◽

Current Data ◽

Atmospheric Composition ◽

Trace Gas ◽

Data Set ◽

Latitude Range ◽

Mixing Ratios ◽

Atmospheric Trace Gas ◽

Chemistry Experiment ◽

Mission Objective

On 12 August 2003, the Canadian-led Atmospheric Chemistry Experiment (ACE) was launched into a 74° inclination orbit at 650 km with the mission objective to measure atmospheric composition using infrared and UV-visible spectroscopy (Bernath et al. 2005). The ACE mission consists of two main instruments, ACE-FTS and MAESTRO (McElroy et al. 2007), which are being used to investigate the chemistry and dynamics of the Earth’s atmosphere. Here, we focus on the high resolution (0.02 cm-1) infrared Fourier Transform Spectrometer, ACE-FTS, that measures in the 750-4400 cm-1 (2.2 to 13.3 µm) spectral region. This instrument has been making regular solar occultation observations for more than nine years. The current ACE-FTS data version (version 3.0) provides profiles of temperature and volume mixing ratios (VMRs) of more than 30 atmospheric trace gas species, as well as 20 subsidiary isotopologues of the most abundant trace atmospheric constituents over a latitude range of ~85°N to ~85°S. This letter describes the current data version and recent validation comparisons and provides a description of our planned updates for the ACE-FTS data set. [...]

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Validation of ACE-FTS N<sub>2</sub>O measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-4759-2008 ◽

2008 ◽

Vol 8 (16) ◽

pp. 4759-4786 ◽

Cited By ~ 55

Author(s):

K. Strong ◽

M. A. Wolff ◽

T. E. Kerzenmacher ◽

K. A. Walker ◽

P. F. Bernath ◽

...

Keyword(s):

Fourier Transform ◽

Atmospheric Chemistry ◽

Relative Difference ◽

Negative Bias ◽

Solar Occultation ◽

The Mean ◽

Single Balloon ◽

Relative Differences ◽

Chemistry Experiment

Abstract. The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar occultation technique. One of these instruments, the ACE Fourier Transform Spectrometer (ACE-FTS), is measuring volume mixing ratio (VMR) profiles of nitrous oxide (N2O) from the upper troposphere to the lower mesosphere at a vertical resolution of about 3–4 km. In this study, the quality of the ACE-FTS version 2.2 N2O data is assessed through comparisons with coincident measurements made by other satellite, balloon-borne, aircraft, and ground-based instruments. These consist of vertical profile comparisons with the SMR, MLS, and MIPAS satellite instruments, multiple aircraft flights of ASUR, and single balloon flights of SPIRALE and FIRS-2, and partial column comparisons with a network of ground-based Fourier Transform InfraRed spectrometers (FTIRs). Between 6 and 30 km, the mean absolute differences for the satellite comparisons lie between −42 ppbv and +17 ppbv, with most within ±20 ppbv. This corresponds to relative deviations from the mean that are within ±15%, except for comparisons with MIPAS near 30 km, for which they are as large as 22.5%. Between 18 and 30 km, the mean absolute differences for the satellite comparisons are generally within ±10 ppbv. From 30 to 60 km, the mean absolute differences are within ±4 ppbv, and are mostly between −2 and +1 ppbv. Given the small N2O VMR in this region, the relative deviations from the mean are therefore large at these altitudes, with most suggesting a negative bias in the ACE-FTS data between 30 and 50 km. In the comparisons with the FTIRs, the mean relative differences between the ACE-FTS and FTIR partial columns (which cover a mean altitude range of 14 to 27 km) are within ±5.6% for eleven of the twelve contributing stations. This mean relative difference is negative at ten stations, suggesting a small negative bias in the ACE-FTS partial columns over the altitude regions compared. Excellent correlation (R=0.964) is observed between the ACE-FTS and FTIR partial columns, with a slope of 1.01 and an intercept of −0.20 on the line fitted to the data.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-2421-2008 ◽

2008 ◽

Vol 8 (9) ◽

pp. 2421-2435 ◽

Cited By ~ 73

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

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Validation of ACE-FTS N<sub>2</sub>O measurements

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-3597-2008 ◽

2008 ◽

Vol 8 (1) ◽

pp. 3597-3663 ◽

Cited By ~ 2

Author(s):

K. Strong ◽

M. A. Wolff ◽

T. E. Kerzenmacher ◽

K. A. Walker ◽

P. F. Bernath ◽

...

Keyword(s):

Fourier Transform ◽

Atmospheric Chemistry ◽

Relative Difference ◽

Negative Bias ◽

Solar Occultation ◽

The Mean ◽

Single Balloon ◽

Relative Differences ◽

Chemistry Experiment

Abstract. The Atmospheric Chemistry Experiment (ACE), also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar occultation technique. One of these instruments, the ACE Fourier Transform Spectrometer (ACE-FTS), is measuring volume mixing ratio (VMR) profiles of nitrous oxide (N2O) from the upper troposphere to the lower mesosphere at a vertical resolution of about 3–4 km. In this study, the quality of the ACE-FTS version 2.2 N2O data is assessed through comparisons with coincident measurements made by other satellite, balloon-borne, aircraft, and ground-based instruments. These consist of vertical profile comparisons with the SMR, MLS, and MIPAS satellite instruments, multiple aircraft flights of ASUR, and single balloon flights of SPIRALE and FIRS-2, and partial column comparisons with a network of ground-based Fourier Transform InfraRed spectrometers (FTIRs). Overall, the quality of the ACE-FTS version 2.2 N2O VMR profiles is good over the entire altitude range from 5 to 60 km. Between 6 and 30 km, the mean absolute differences for the satellite comparisons lie between −42 ppbv and +17 ppbv, with most within ±20 ppbv. This corresponds to relative deviations from the mean that are within ±15%, except for comparisons with MIPAS near 30 km, for which they are as large as 22.5%. Between 18 and 30 km, the mean absolute differences are generally within ±10 ppbv, again excluding the aircraft and balloon comparisons. From 30 to 60 km, the mean absolute differences are within ±4 ppbv, and are mostly between −2 and +1 ppbv. Given the small N2O VMR in this region, the relative deviations from the mean are therefore large at these altitudes, with most suggesting a negative bias in the ACE-FTS data between 30 and 50 km. In the comparisons with the FTIRs, the mean relative differences between the ACE-FTS and FTIR partial columns are within ±6.6% for eleven of the twelve contributing stations. This mean relative difference is negative at ten stations, suggesting a small negative bias in the ACE-FTS partial columns over the altitude regions compared. Excellent correlation (R=0.964) is observed between the ACE-FTS and FTIR partial columns, with a slope of 1.01 and an intercept of −0.20 on the line fitted to the data.

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Case studies of the impact of orbital sampling on stratospheric trend detection and derivation of tropical vertical velocities: solar occultation vs. limb emission sounding

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-11521-2016 ◽

2016 ◽

Vol 16 (18) ◽

pp. 11521-11534 ◽

Cited By ~ 9

Author(s):

Luis F. Millán ◽

Nathaniel J. Livesey ◽

Michelle L. Santee ◽

Jessica L. Neu ◽

Gloria L. Manney ◽

...

Keyword(s):

Case Studies ◽

Atmospheric Chemistry ◽

Stratospheric Ozone ◽

Sampling Bias ◽

Nonuniform Sampling ◽

Trend Detection ◽

Trace Gas ◽

Uniform Sampling ◽

Solar Occultation ◽

The Impact

Abstract. This study investigates the representativeness of two types of orbital sampling applied to stratospheric temperature and trace gas fields. Model fields are sampled using real sampling patterns from the Aura Microwave Limb Sounder (MLS), the HALogen Occultation Experiment (HALOE) and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). The MLS sampling acts as a proxy for a dense uniform sampling pattern typical of limb emission sounders, while HALOE and ACE-FTS represent coarse nonuniform sampling patterns characteristic of solar occultation instruments. First, this study revisits the impact of sampling patterns in terms of the sampling bias, as previous studies have done. Then, it quantifies the impact of different sampling patterns on the estimation of trends and their associated detectability. In general, we find that coarse nonuniform sampling patterns may introduce non-negligible errors in the inferred magnitude of temperature and trace gas trends and necessitate considerably longer records for their definitive detection. Lastly, we explore the impact of these sampling patterns on tropical vertical velocities derived from stratospheric water vapor measurements. We find that coarse nonuniform sampling may lead to a biased depiction of the tropical vertical velocities and, hence, to a biased estimation of the impact of the mechanisms that modulate these velocities. These case studies suggest that dense uniform sampling such as that available from limb emission sounders provides much greater fidelity in detecting signals of stratospheric change (for example, fingerprints of greenhouse gas warming and stratospheric ozone recovery) than coarse nonuniform sampling such as that of solar occultation instruments.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-505-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 505-522 ◽

Cited By ~ 62

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.

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Validation of MIPAS IMK/IAA methane profiles

Atmospheric Measurement Techniques ◽

10.5194/amt-8-5251-2015 ◽

2015 ◽

Vol 8 (12) ◽

pp. 5251-5261 ◽

Cited By ~ 16

Author(s):

A. Laeng ◽

J. Plieninger ◽

T. von Clarmann ◽

U. Grabowski ◽

G. Stiller ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Michelson Interferometer ◽

European Space Agency ◽

Trace Gas ◽

Mixing Ratios ◽

Air Sampler ◽

Solar Occultation ◽

Space Agency ◽

Scanning Imaging ◽

Satellite Instruments

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is an infrared (IR) limb emission spectrometer on the Envisat platform. It measures trace gas distributions during day and night, pole-to-pole, over an altitude range from 6 to 70 km in nominal mode and up to 170 km in special modes, depending on the measurement mode, producing more than 1000 profiles day−1. We present the results of a validation study of methane, version V5R_CH4_222, retrieved with the IMK/IAA (Institut für Meteorologie und Klimaforschung, Karlsruhe/Instituto de Astrofisica de Andalucia, Grenada) MIPAS scientific level 2 processor. The level 1 spectra are provided by the ESA (European Space Agency) and version 5 was used. The time period covered is 2005–2012, which corresponds to the period when MIPAS measured trace gas distributions at a reduced spectral resolution of 0.0625 cm−1. The comparison with satellite instruments includes the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS), the HALogen Occultation Experiment (HALOE), the Solar Occultation For Ice Experiment (SOFIE) and the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY). Furthermore, comparisons with MkIV balloon-borne solar occultation measurements and with air sampling measurements performed by the University of Frankfurt are presented. The validation activities include bias determination, assessment of stability, precision validation, analysis of histograms and comparison of corresponding climatologies. Above 50 km altitude, MIPAS methane mixing ratios agree within 3 % with ACE-FTS and SOFIE. Between 30 and 40 km an agreement within 3 % with SCIAMACHY has been found. In the middle stratosphere, there is no clear indication of a MIPAS bias since comparisons with various instruments contradict each other. In the lower stratosphere (below 25 km) MIPAS CH4 is biased high with respect to satellite instruments, and the most likely estimate of this bias is 14 %. However, in the comparison with CH4 data obtained from cryogenic whole-air sampler (cryosampler) measurements, there is no evidence of a high bias in MIPAS between 20 and 25 km altitude. Precision validation is performed on collocated MIPAS–MIPAS pairs and suggests a slight underestimation of its uncertainties by a factor of 1.2. No significant evidence of an instrumental drift has been found.

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Sunset–sunrise difference in solar occultation ozone measurements (SAGE II, HALOE, and ACE–FTS) and its relationship to tidal vertical winds

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-16043-2014 ◽

2014 ◽

Vol 14 (11) ◽

pp. 16043-16083

Author(s):

T. Sakazaki ◽

M. Shiotani ◽

M. Suzuki ◽

D. Kinnison ◽

J. M. Zawodny ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Seasonal Variations ◽

Climate Model ◽

Transport Model ◽

Stratospheric Aerosol ◽

Chemical Transport Model ◽

Latitude Range ◽

Solar Occultation ◽

Vertical Winds ◽

Chemistry Experiment

Abstract. This paper contains a comprehensive investigation of the sunset–sunrise difference (SSD; i.e., the sunset-minus-sunrise value) of the ozone mixing ratio in the latitude range of 10° S–10° N. SSD values were determined from solar occultation measurements based on data obtained from the Stratospheric Aerosol and Gas Experiment (SAGE) II, the Halogen Occultation Experiment (HALOE), and the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). The SSD was negative at altitudes of 20–30 km (–0.1 ppmv at 25 km) and positive at 30–50 km (+0.2 ppmv at 40–45 km) for HALOE and ACE–FTS data. SAGE II data also showed a qualitatively similar result, although the SSD in the upper stratosphere was two times larger than those derived from the other datasets. On the basis of an analysis of data from the Superconducting Submillimeter Limb Emission Sounder (SMILES), and a nudged chemical-transport model (the Specified Dynamics version of the Whole Atmosphere Community Climate Model: SD–WACCM), we conclude that the SSD can be explained by diurnal variations in the ozone concentration, particularly those caused by vertical transport by the atmospheric tidal winds. All datasets showed significant seasonal variations in the SSD; the SSD in the upper stratosphere is greatest from December through February, while that in the lower stratosphere reaches a maximum twice: during the periods March–April and September–October. Based on an analysis of SD–WACCM results, we found that these seasonal variations follow those associated with the tidal vertical winds.

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