scholarly journals Comparison of the inversion algorithms applied to the ozone vertical profile retrieval from SCIAMACHY limb measurements

2007 ◽  
Vol 7 (1) ◽  
pp. 1969-1993
Author(s):  
A. Rozanov ◽  
K.-U. Eichmann ◽  
C. von Savigny ◽  
H. Bovensmann ◽  
J. P. Burrows ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
European Space Agency ◽  
Vertical Profiles ◽  
Upper Troposphere ◽  
Operational Level ◽  
Space Agency ◽  
Lidar Measurements ◽  
Level 1 ◽  
Ground Based Lidar ◽  
Middle Stratosphere

Abstract. This paper is devoted to an intercomparison of ozone vertical profiles retrieved from the measurements of scattered solar radiation performed by the SCIAMACHY instrument in the limb viewing geometry. Three different inversion algorithms including the prototype of the operational Level 1 to 2 processor to be operated by the European Space Agency are considered. The intercomparison was performed for 5 selected orbits of SCIAMACHY showing a good overall agreement of the results in the middle stratosphere, whereas considerable discrepancies were identified in the lower stratosphere and upper troposphere altitude region. Additionally, comparisons with ground-based lidar measurements are shown for selected profiles demonstrating an overall correctness of the retrievals.

scholarly journals Comparison of the inversion algorithms applied to the ozone vertical profile retrieval from SCIAMACHY limb measurements

2007 ◽  
Vol 7 (18) ◽  
pp. 4763-4779 ◽  
Author(s):  
A. Rozanov ◽  
K.-U. Eichmann ◽  
C. von Savigny ◽  
H. Bovensmann ◽  
J. P. Burrows ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
European Space Agency ◽  
Air Masses ◽  
Upper Troposphere ◽  
Space Agency ◽  
Lidar Measurements ◽  
Retrieval Problem ◽  
Level 1 ◽  
Ground Based Lidar ◽  
Middle Stratosphere

Abstract. This paper is devoted to an intercomparison of ozone vertical profiles retrieved from the measurements of scattered solar radiation performed by the SCIAMACHY instrument in the limb viewing geometry. Three different inversion algorithms including the prototype of the operational Level 1 to 2 processor to be operated by the European Space Agency are considered. Unlike usual validation studies, this comparison removes the uncertainties arising when comparing measurements made by different instruments probing slightly different air masses and focuses on the uncertainties specific to the modeling-retrieval problem only. The intercomparison was performed for 5 selected orbits of SCIAMACHY showing a good overall agreement of the results in the middle stratosphere, whereas considerable discrepancies were identified in the lower stratosphere and upper troposphere altitude region. Additionally, comparisons with ground-based lidar measurements are shown for selected profiles demonstrating an overall correctness of the retrievals.

scholarly journals CCl<sub>4</sub> distribution derived from MIPAS ESA V7 data: validation, trend and lifetime estimation

2017 ◽  
Author(s):  
Massimo Valeri ◽  
Flavio Barbara ◽  
Chris Boone ◽  
Simone Ceccherini ◽  
Marco Gai ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Montreal Protocol ◽  
Average Lifetime ◽  
Atmospheric Emissions ◽  
Industrial Countries ◽  
Upper Troposphere ◽  
Space Agency ◽  
Atmospheric Observations

Abstract. Atmospheric emissions of Carbon tetrachloride CCl4 are regulated by the Montreal Protocol due to its role as a strong ozone-depleting substance. The molecule has been the subject of recent increased interest as a consequence of the so called ``mystery of CCl4,'' the discrepancy between atmospheric observations and reported production and consumption. Surface measurements of CCl4 atmospheric concentrations have declined at a rate almost three times smaller than its lifetime-limited rate, suggesting persistent atmospheric emissions despite the ban. In this paper, we study CCl4 vertical and zonal distributions in the upper troposphere and lower stratosphere (including the photolytic loss region, 70–20 hPa), its trend, and its stratospheric lifetime using measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which operated onboard the ENVISAT satellite from 2002 to 2012. Specifically, we use the MIPAS data product generated with Version 7 of the Level 2 algorithm operated by the European Space Agency. The CCl4 zonal means show features typical of long-lived species of anthropogenic origin that are destroyed primarily in the stratosphere, with larger quantities in the troposphere and a monotonic decrease with increasing altitude in the stratosphere. In the troposphere, the largest concentrations are observed at the latitudes of major industrial countries (20/50°N). The good agreement we find between MIPAS CCl4 and independent measurements from other satellite and balloon-borne remote sounders proves the reliability of the MIPAS dataset. CCl4 trends are calculated as a function of both latitude and altitude. Negative trends are found at all latitudes in the upper-troposphere / lower-stratosphere region, apart from a region in the Southern mid-latitudes between 50 and 10 hPa where the trend is positive. At the lowest altitudes sounded by MIPAS, we find trends consistent with those determined on the basis of long-term ground-based measurements. For higher altitudes, the trend shows a pronounced asymmetry between Northern and Southern Hemispheres, and the magnitude of the decline rate increases with altitude. At 50 hPa the decline is about 30–35 %/decade, close to the lifetime-limited trend. We use a simplified model assuming tracer-tracer linear correlations to determine CCl4 lifetime in the lower stratosphere. The calculation provides a global average lifetime of 46(38–60) years considering CFC-11 as the reference tracer. This value is consistent with the most recent literature result of 44(36–58) years.

scholarly journals Two-dimensional performance of MIPAS observation modes in the upper-troposphere/lower-stratosphere

2010 ◽  
Vol 3 (4) ◽  
pp. 2861-2890
Author(s):  
M. Carlotti ◽  
E. Papandrea ◽  
E. Castelli
Keyword(s):  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Horizontal Resolution ◽  
Information Load ◽  
Two Dimensional ◽  
Upper Troposphere ◽  
Space Agency ◽  
Spatial Coverage ◽  
Load Analysis

Abstract. In this paper we analyze the performance of the three MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) observation modes that sound the Upper-Troposphere/Lower-Stratosphere (UT/LS) region. The two-dimensional (2-D) tomographic retrieval approach is assumed to derive the atmospheric field of geophysical parameters. For each observation mode we have calculated the 2-D distribution of the information load quantifier relative to the main MIPAS targets. The performance of the observation modes is then evaluated in terms of strength, spatial coverage and uniformity of the information-load distribution along the full orbit. The outcome of the information-load analysis has been validated with simulated retrievals based on the observational parameters of real orbits. With this strategy we have assessed the precision and the spatial (both horizontal and vertical) resolution of the retrieval products. The performance of the three observation modes has been compared for the MIPAS main products in both the UT/LS and the extended altitude range. This study shows that the two observation modes that were specifically designed for the UT/LS region are actually competitive with the third one, designed for the whole stratosphere, up to altitudes that far exceed the UT/LS. In the UT/LS the performance of the two specific observation modes is comparable even if the best performance in terms of horizontal resolution is provided by the observation mode that was excluded by the European Space Agency (ESA) from the current MIPAS duty cycle. This paper reports the first application of the information-load analysis and highlights the validity of this approach.

scholarly journals Results of the preparatory study “PREMIER Analysis of Campaign Data”

2014 ◽  
Author(s):  
Elisa Castelli ◽  
Samuele Del Bianco ◽  
Bianca Maria Dinelli ◽  
Daniel Gerber ◽  
Hermann Oelhaf ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
European Space Agency ◽  
Major Focus ◽  
Upper Troposphere ◽  
Atmospheric Research ◽  
Radiative Processes ◽  
Research Activities ◽  
Space Agency ◽  
The Impact

The relevance of the UTLS (Upper Troposphere and Lower Stratosphere) region and the impact of limb emission<br />measurements at millimetre and sub-millimetre wavelengths for investigation of chemical, dynamical and<br />radiative processes occurring at these altitudes constitute a major focus of the atmospheric research activities<br />supported by the European Space Agency (ESA) in the last two decades.[...]

scholarly journals Two-dimensional performance of MIPAS observation modes in the upper-troposphere/lower-stratosphere

2011 ◽  
Vol 4 (2) ◽  
pp. 355-365 ◽  
Author(s):  
M. Carlotti ◽  
E. Castelli ◽  
E. Papandrea
Keyword(s):  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Horizontal Resolution ◽  
Information Load ◽  
Two Dimensional ◽  
Upper Troposphere ◽  
Space Agency ◽  
Spatial Coverage ◽  
Load Analysis

Abstract. In this paper we analyze the performance of the three MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) observation modes that sound the Upper-Troposphere/Lower-Stratosphere (UT/LS) region. The two-dimensional (2-D) tomographic retrieval approach is assumed to derive the atmospheric field of geophysical parameters. For each observation mode we have calculated the 2-D distribution of the information load quantifier relative to the main MIPAS targets. The performance of the observation modes has been evaluated in terms of strength and spatial coverage of the information-load distribution along the full orbit. The indications of the information-load analysis has been validated with simulated retrievals based on the observational parameters of real orbits. In the simulation studies we have assessed the precision and the spatial (both horizontal and vertical) resolution of the retrieval products. The performance of the three observation modes has been compared for the MIPAS main products in both the UT/LS and the extended altitude range. This study shows that the two observation modes that were specifically designed for the UT/LS region are actually competitive with the third one, designed for the whole stratosphere, up to altitudes that far exceed the UT/LS. In the UT/LS the performance of the two specific observation modes is comparable even if the best performance in terms of horizontal resolution is provided by the observation mode that was excluded by the European Space Agency (ESA) from the current MIPAS duty cycle. This paper reports the first application of the information-load analysis and highlights the worthiness of this approach to make qualitative considerations about retrieval potential and selection of retrieval grid.

scholarly journals OLCI A/B Tandem Phase Analysis, Part 1: Level 1 Homogenisation and Harmonisation

2020 ◽  
Vol 12 (11) ◽  
pp. 1804 ◽  
Author(s):  
Nicolas Lamquin ◽  
Sébastien Clerc ◽  
Ludovic Bourg ◽  
Craig Donlon
Keyword(s):  
European Space Agency ◽  
Companion Paper ◽  
The Other ◽  
Satellite Mission ◽  
Space Agency ◽  
The Future ◽  
Level 1 ◽  
Level 2 ◽  
Very High ◽  
Sentinel 2

Copernicus is a European system for monitoring the Earth in support of European policy. It includes the Sentinel-3 satellite mission which provides reliable and up-to-date measurements of the ocean, atmosphere, cryosphere, and land. To fulfil mission requirements, two Sentinel-3 satellites are required on-orbit at the same time to meet revisit and coverage requirements in support of Copernicus Services. The inter-unit consistency is critical for the mission as more S3 platforms are planned in the future. A few weeks after its launch in April 2018, the Sentinel-3B satellite was manoeuvred into a tandem configuration with its operational twin Sentinel-3A already in orbit. Both satellites were flown only thirty seconds apart on the same orbit ground track to optimise cross-comparisons. This tandem phase lasted from early June to mid October 2018 and was followed by a short drift phase during which the Sentinel-3B satellite was progressively moved to a specific orbit phasing of 140° separation from the sentinel-3A satellite. In this paper, an output of the European Space Agency (ESA) Sentinel-3 Tandem for Climate study (S3TC), we provide a full methodology for the homogenisation and harmonisation of the two Ocean and Land Colour Instruments (OLCI) based on the tandem phase. Homogenisation adjusts for unavoidable slight spatial and spectral differences between the two sensors and provide a basis for the comparison of the radiometry. Persistent radiometric biases of 1–2% across the OLCI spectrum are found with very high confidence. Harmonisation then consists of adjusting one instrument on the other based on these findings. Validation of the approach shows that such harmonisation then procures an excellent radiometric alignment. Performed on L1 calibrated radiances, the benefits of harmonisation are fully appreciated on Level 2 products as reported in a companion paper. Whereas our methodology aligns one sensor to behave radiometrically as the other, discussions consider the choice of the reference to be used within the operational framework. Further exploitation of the measurements indeed provides evidence of the need to perform flat-fielding on both payloads, prior to any harmonisation. Such flat-fielding notably removes inter-camera differences in the harmonisation coefficients. We conclude on the extreme usefulness of performing a tandem phase for the OLCI mission continuity as well as for any optical mission to which the methodology presented in this paper applies (e.g., Sentinel-2). To maintain the climate record, it is highly recommended that the future Sentinel-3C and Sentinel-3D satellites perform tandem flights when injected into the Sentinel-3 time series.

scholarly journals Ground-based water vapor raman lidar measurements up to the upper troposphere and lower stratosphere for long-term monitoring

2012 ◽  
Vol 5 (1) ◽  
pp. 17-36 ◽  
Author(s):  
T. Leblanc ◽  
I. S. McDermid ◽  
T. D. Walsh
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Lower Troposphere ◽  
Atmospheric Composition ◽  
Raman Lidar ◽  
Upper Troposphere ◽  
Lidar Measurements ◽  
Development Data ◽  
Instrumental Development

Abstract. Recognizing the importance of water vapor in the upper troposphere and lower stratosphere (UTLS) and the scarcity of high-quality, long-term measurements, JPL began the development of a powerful Raman lidar in 2005 to try to meet these needs. This development was endorsed by the Network for the Detection of Atmospheric Composition Change (NDACC) and the validation program for the EOS-Aura satellite. In this paper we review the stages in the instrumental development, data acquisition and analysis, profile retrieval and calibration procedures of the lidar, as well as selected results from three validation campaigns: MOHAVE (Measurements of Humidity in the Atmosphere and Validation Experiments), MOHAVE-II, and MOHAVE 2009. In particular, one critical result from this latest campaign is the very good agreement (well below the reported uncertainties) observed between the lidar and the Cryogenic Frost-Point Hygrometer in the entire lidar range 3–20 km, with a mean bias not exceeding 2% (lidar dry) in the lower troposphere, and 3% (lidar moist) in the UTLS. Ultimately the lidar has demonstrated capability to measure water vapor profiles from ∼1 km above the ground to the lower stratosphere with a precision of 10% or better near 13 km and below, and an estimated accuracy of 5%. Since 2005, nearly 1000 profiles have been routinely measured, and since 2009, the profiles have typically reached 14 km for one-hour integration times and 1.5 km vertical resolution, and can reach 21 km for 6-h integration times using degraded vertical resolutions. These performance figures show that, with our present target of routinely running our lidar two hours per night, 4 nights per week, we can achieve measurements with a precision in the UTLS equivalent to that achieved if launching one CFH per month.

scholarly journals Direct inversion of circulation from tracer measurements – Part 2: Sensitivity studies and model recovery tests

2020 ◽  
Author(s):  
Thomas von Clarmann ◽  
Udo Grabowski
Keyword(s):  
Lower Stratosphere ◽  
Velocity Fields ◽  
Trace Gas ◽  
Meridional Transport ◽  
Upper Troposphere ◽  
Direct Inversion ◽  
Circulation Patterns ◽  
Sensitivity Studies ◽  
Reference Fields ◽  
Middle Stratosphere

Abstract. The direct inversion of the 2D continuity equation allows to infer the effective meridional transport of trace gases in the middle stratosphere. This methods exploits the information both given by the displacement of patterns in measured trace gas distributions and by the approximate balance between sinks and horizontal as well as vertical advection. Model recovery tests have shown that with the current setup of the algorithm, this method reliably reproduces the circulation patterns in the entire analysis domain from 6 to 66 km altitude. Due to the regularization of the inversion, velocities above about 30 km are more likely under- than overestimated. This is explained by the fact that the measured trace gas distributions at higher altitudes generally contain less information and that the regularization of the inversion pushes results towards zero. Weaker regularization would in some cases allow a more accurate recovery of the velocity fields. However, there is a price to pay in that the risk of convergence failure increases. No instance was found where the algorithm generated artificial patterns not present in the reference fields. Most information on effective velocities above 50 km is included in measurements of CH4, CO, H2O, and N2O, while CFC-11, HCFC-22, and CFC-12 constrain the inversion most efficiently in the middle stratosphere. H2O is a particularly important tracer in the upper troposphere/lower stratosphere. SF6 and CCl4 contain generally less information but still contribute to the reduction of the estimated uncertainties.

scholarly journals Observational evidence of particle condensational growth in the UTLS over Tibetan Plateau

2019 ◽  
Author(s):  
Qianshan He ◽  
Jianzhong Ma ◽  
Xiangdong Zheng ◽  
Xiaolu Yan ◽  
Holger Vömel ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Lower Stratosphere ◽  
Fine Particles ◽  
Observational Evidence ◽  
Aerosol Layer ◽  
Vertical Profiles ◽  
Small Particles ◽  
Upper Troposphere ◽  
Condensational Growth ◽  
Aerosol Backscatter

Abstract. We measured the vertical profiles of aerosol backscattering ratio (BSR) with a balloon-borne lightweight COBALD at Linzhi, located in the southeastern Tibetan Plateau, in the summer of 2014. An enhanced aerosol layer in the upper troposphere/lower stratosphere (UTLS) are found), with BSR (455 nm) > 1.1 and BSR (940 nm) > 1.4., was observed. The Color Index (CI) of the enhanced aerosol layer, defined as the ratio of aerosol backscatter ratios at wavelengths of 940 nm and 455 nm, varied from 4 to 8, indicating the prevalence of dominant fine particles with mode radius less than 0.1 μm. For those aerosol We find that except for the very small particles with (mode radius smaller than 0.04 μm) at low relative humidity (RHi 

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