Retrieval and validation of MetOp/IASI methane

Abstract. A new IASI methane product developed at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) is presented. The retrievals are performed with the ASIMUT-ALVL software based on the optimal estimation method (OEM). This paper gives an overview of the forward model and retrieval concept. The usefulness of reconstructed principal component compressed (PCC) radiances is highlighted. The information content study carried out in this paper shows that most IASI pixels contain between 0.9 and 1.6 independent pieces of information about the vertical distribution of CH4, with a good sensitivity in the mid- to upper troposphere. A detailed error analysis was performed. The total uncertainty is estimated to be 3.73 % for a CH4 partial column between 4 and 17 km. An extended validation with ground-based CH4 observations at 10 locations was carried out. IASI CH4 partial columns are found to correlate well with the ground-based data for 6 out of the 10 Fourier transform infrared (FTIR) stations with correlation coefficients between 0.60 and 0.84. Relative mean differences between IASI and FTIR CH4 range between −2.31 and 4.04 % and are within the systematic uncertainty. For 6 out of the 10 stations the relative mean differences are smaller than ±1 %. The standard deviation of the difference lies between 1.76 and 2.97 % for all the stations.

Download Full-text

Retrieval and validation of METOP/IASI methane

10.5194/amt-2017-165 ◽

2017 ◽

Author(s):

Evelyn De Wachter ◽

Nicolas Kumps ◽

Ann Carine Vandaele ◽

Bavo Langerock ◽

Martine De Mazière

Keyword(s):

Fourier Transform ◽

Estimation Method ◽

Correlation Coefficients ◽

Principal Component ◽

Optimal Estimation ◽

Good Sensitivity ◽

Upper Troposphere ◽

The Difference ◽

Mean Differences ◽

The Vertical Distribution

Abstract. A new global IASI methane product developed at the Royal Belgian Institute for Space Aeronomy (BIRA-IASB) is presented. The retrievals are performed with the ASIMUT-ALVL software based on the Optimal Estimation Method (OEM). This paper gives an overview of the forward model and retrieval concept. The usefullness of reconstructed Principal Component Compressed (PCC) radiances is highlighted. The retrieval uncertainty of the CH4 profiles is less than 4 % below 100 hPa (~ 16 km). The information content study carried out in this paper shows that most IASI pixels contain between 0.9 and 1.6 independent pieces of information about the vertical distribution of CH4, with a good sensitivity in the mid to upper troposphere. An extended validation with ground-based CH4 observations at 10 locations was carried out. IASI CH4 partial columns are found to correlate well with the ground-based data for 7 out of the 10 Fourier Transform Infrared (FTIR) stations with correlation coefficients between 0.71 and 0.96. Mean differences between IASI and FTIR CH4 range between −1.93 and 4.40 % and are within the systematic uncertainty. For 7 out of the 10 stations absolute differences are less than 1 %. The standard deviation of the difference lies between 1.40 and 3.99 % for all the stations.

Download Full-text

Solar occultation with SCIAMACHY: algorithm description and first validation

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-17-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 17-66 ◽

Cited By ~ 1

Author(s):

J. Meyer ◽

A. Bracher ◽

A. Rozanov ◽

A. C. Schlesier ◽

H. Bovensmann ◽

...

Keyword(s):

Vertical Profile ◽

Estimation Method ◽

Optimal Estimation ◽

Trace Gas ◽

Transmission Spectra ◽

Atmospheric Transmission ◽

Gas Concentration ◽

Solar Occultation ◽

First Results ◽

The Vertical Distribution

Abstract. This presentation concentrates on solar occultation measurements with the spaceborne spectrometer SCIAMACHY in the UV-Vis wavelength range. Solar occultation measurements provide unique information about the vertical distribution of atmospheric constituents. For retrieval of vertical trace gas concentration profiles, an algorithm has been developed based on the optimal estimation method. The forward model is capable to simulate the extinction signals of different species as they occur in atmospheric transmission spectra obtained from occultation measurements. Furthermore, correction algorithms have been implemented to address shortcomings of the tangent height pre-processing and inhomogeneities of measured solar spectra. First results of O3 and NO2 vertical profile retrievals have been validated with data from ozone sondes and satellite based occultation instruments. The validation shows very promising results for SCIAMACHY O3 and NO2 values between 15 to 35 km with errors in the order of 10% and 15%, respectively.

Download Full-text

Optimal Estimation Method Retrievals of Stratospheric Ozone Profiles from a DIAL Lidar

10.5194/amt-2018-310 ◽

2018 ◽

Author(s):

Ghazal Farhani ◽

Robert J. Sica ◽

Sophie Godin-Beekmann ◽

Alexander Haefele

Keyword(s):

Stratospheric Ozone ◽

A Priori ◽

Estimation Method ◽

Optimal Estimation ◽

Uncertainty Budget ◽

Small Contribution ◽

Vertical Resolution ◽

Density Profiles ◽

Complete Uncertainty ◽

The Difference

Abstract. This paper provides a detailed description of the first principle Optimal Estimation Method (OEM) which is applied to ozone retrieval analysis using Differential Absorption Lidar (DIAL) measurements. The air density, detector dead times, background coefficients, and lidar constants are simultaneously retrieved along with ozone density profiles. Using an averaging kernel, the OEM provides the vertical resolution of the retrieval as a function of altitude. A maximum acceptable height at which the a priori has a small contribution to the retrieval is calculated for each profile as well. Moreover, a complete uncertainty budget including both systematic and statistical uncertainties is given for each individual retrieved profile. Long term stratospheric DIAL ozone measurements have been carried out at the Observatoire de Haute-Provence (OHP) since 1985. The OEM is applied to 3 nights of measurements at OHP during an intensive ozone campaign in July 2017 where coincident lidar-ozonesonde measurements are available. The retrieved ozone density profiles are in good agreement with both traditional analysis and the ozonesonde measurements. For the three nights of measurements, below 15 km the difference between the OEM and the sonde profiles is less than 25 %, at altitudes between 15 km to 25 km the difference is less than 10 %, and the OEM can successfully catch many variations of ozone which are detected in the sonde profiles due to its ability to adjust its vertical resolution as the signal varies. Above 25 km the difference between the OEM and the sonde profiles does not exceed 20 %.

Download Full-text

Global carbon monoxide vertical distributions from spaceborne high-resolution FTIR nadir measurements

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-2901-2005 ◽

2005 ◽

Vol 5 (11) ◽

pp. 2901-2914 ◽

Cited By ~ 40

Author(s):

B. Barret ◽

S. Turquety ◽

D. Hurtmans ◽

C. Clerbaux ◽

J. Hadji-Lazaro ◽

...

Keyword(s):

High Resolution ◽

Estimation Method ◽

Lower Troposphere ◽

Optimal Estimation ◽

Vertical Distributions ◽

Surface Measurements ◽

The Vertical Distribution ◽

Global Carbon ◽

Good Agreement

Abstract. This paper presents the first global distributions of CO vertical profiles retrieved from a thermal infrared FTS working in the nadir geometry. It is based on the exploitation of the high resolution and high quality spectra measured by the Interferometric Monitor of Greenhouse gases (IMG) which flew onboard the Japanese ADEOS platform in 1996-1997. The retrievals are performed with an algorithm based on the Optimal Estimation Method (OEM) and are characterized in terms of vertical sensitivity and error budget. It is found that most of the IMG measurements contain between 1.5 and 2.2 independent pieces of information about the vertical distribution of CO from the lower troposphere to the upper troposphere-lower stratosphere (UTLS). The retrievals are validated against coincident NOAA/CMDL in situ surface measurements and NDSC/FTIR total columns measurements. The retrieved global distributions of CO are also found to be in good agreement with the distributions modeled by the GEOS-CHEM 3D CTM, highlighting the ability of IMG to capture the horizontal as well as the vertical structure of the CO distributions.

Download Full-text

Droplet vertical sizing in warm clouds using passive optical measurements from a satellite

Atmospheric Measurement Techniques ◽

10.5194/amt-5-517-2012 ◽

2012 ◽

Vol 5 (3) ◽

pp. 517-528 ◽

Cited By ~ 12

Author(s):

A. Kokhanovsky ◽

V. V. Rozanov

Keyword(s):

Vertical Profile ◽

Estimation Method ◽

Optimal Estimation ◽

Effective Radius ◽

Optical Measurements ◽

Weighting Functions ◽

Near Ir ◽

Cloud Optical Thickness ◽

The Vertical Distribution

Abstract. In this paper a new algorithm for the determination of the vertical distribution of the droplet effective radius in shallow warm clouds is proposed. The method is based on the fact that the spectral top-of-atmosphere reflectance in the near IR spectral range depends on the vertical profile of the effective radius of droplets. The retrieval is based on the optimal estimation method and direct radiative transfer calculations of respective weighting functions. The applications of the method both to synthetic and satellite data are presented. An important feature of the method is the fact that the cloud optical thickness and cloud effective radius are found using the standard homogeneous cloud retrieval and then the retrievals are improved assuming the type of the droplet effective radius profile.

Download Full-text

Optimal estimation method retrievals of stratospheric ozone profiles from a DIAL

Atmospheric Measurement Techniques ◽

10.5194/amt-12-2097-2019 ◽

2019 ◽

Vol 12 (4) ◽

pp. 2097-2111 ◽

Cited By ~ 2

Author(s):

Ghazal Farhani ◽

Robert J. Sica ◽

Sophie Godin-Beekmann ◽

Alexander Haefele

Keyword(s):

Stratospheric Ozone ◽

A Priori ◽

Estimation Method ◽

Optimal Estimation ◽

Uncertainty Budget ◽

Small Contribution ◽

Vertical Resolution ◽

Density Profiles ◽

Complete Uncertainty ◽

The Difference

Abstract. This paper provides a detailed description of a first-principle optimal estimation method (OEM) applied to ozone retrieval analysis using differential absorption lidar (DIAL) measurements. The air density, detector dead times, background coefficients, and lidar constants are simultaneously retrieved along with ozone density profiles. Using an averaging kernel, the OEM provides the vertical resolution of the retrieval as a function of altitude. A maximum acceptable height at which the a priori has a small contribution to the retrieval is calculated for each profile as well. Moreover, a complete uncertainty budget including both systematic and statistical uncertainties is given for each individual retrieved profile. Long-term stratospheric DIAL ozone measurements have been carried out at the Observatoire de Haute-Provence (OHP) since 1985. The OEM is applied to three nights of measurements at OHP during an intensive ozone campaign in July 2017 for which coincident lidar–ozonesonde measurements are available. The retrieved ozone density profiles are in good agreement with both traditional analysis and the ozonesonde measurements. For the three nights of measurements, below 15 km the difference between the OEM and the sonde profiles is less than 25 %, and at altitudes between 15 and 25 km the difference is less than 10 %; the OEM can successfully catch many variations in ozone, which are detected in the sonde profiles due to its ability to adjust its vertical resolution as the signal varies. Above 25 km the difference between the OEM and the sonde profiles does not exceed 20 %.

Download Full-text

The Effect of Phosphorus Metabolism on the Motion of Saccharomyces cerevisiae Volutin Granules

Mikrobiolohichnyi Zhurnal ◽

10.15407/microbiolj83.03.046 ◽

2021 ◽

Vol 83 (3) ◽

pp. 46-55

Author(s):

M.S. Kharchuk ◽

◽

E.N. Gromozova ◽

Keyword(s):

Saccharomyces Cerevisiae ◽

Correlation Coefficients ◽

Principal Component ◽

Phosphorus Metabolism ◽

Inorganic Polyphosphates ◽

Study Results ◽

Linear Correlation Analysis ◽

The Difference ◽

Polyphosphate Metabolism ◽

Number Of Cells

It is known that moving volutin granules (“dancing bodies”), mechanism of which occurrence remains poorly understood, can be observed in yeast vacuoles. This study was performed to reveal the presence of a connection between moving volutin granules of Saccharomyces cerevisiae and polyphosphate metabolism in conditions of phosphoric starvation and hypercompensation. Methods. Cytological, biochemical, statistical methods were used in the study. Results. It was observed that the inactivation of the PPN1 gene, which encodes exopolyphosphatase Ppn1, resulted in a change in the number of cells with moving volutin granules (“dancing bodies” index) in the studied conditions. The index of “dancing bodies” was almost always lower in mutant CRN strain than in parent CRY strain. Using linear correlation analysis and factor analysis with the method of principal component, it was established that the “dancing bodies” index in both strains had significant correlation coefficients with exopolyphosphatase activity (EPPA) and the content of polyphosphate fractions (polyP). The difference was that this index in parent strain correlated better with the first three fractions of inorganic polyphosphates, while in mutant strain – with polyP4 and EPPA. Conclusions. Obtained data indicated the direct connection of motion of volutin granules with phosphoric metabolism in the studied conditions. It is assumed that the phenomenon of “dancing bodies” may be a consequence of the activity of vacuolar polyphosphatases.

Download Full-text

Validation of stratospheric water vapour measurements from the airborne microwave radiometer AMSOS

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-1635-2008 ◽

2008 ◽

Vol 8 (1) ◽

pp. 1635-1671 ◽

Cited By ~ 2

Author(s):

S. C. Müller ◽

N. Kämpfer ◽

D. G. Feist ◽

A. Haefele ◽

M. Milz ◽

...

Keyword(s):

Water Vapour ◽

Microwave Radiometer ◽

Estimation Method ◽

Optimal Estimation ◽

Horizontal Resolution ◽

Polar Regions ◽

Upper Troposphere ◽

Vertical Range ◽

Stratospheric Water Vapour

Abstract. We present the validation of a water vapour dataset obtained by the Airborne Microwave Stratospheric Observing System AMSOS, a passive microwave radiometer operating at 183 GHz. Vertical profiles are retrieved from spectra by an optimal estimation method. The useful vertical range lies in the upper troposphere up to the mesosphere with an altitude resolution of 8 to 16 km and a horizontal resolution of about 57 km. Flight campaigns were performed once a year from 1998 to 2006 measuring the latitudinal distribution of water vapour from the tropics to the polar regions. The obtained profiles show clearly the main features of stratospheric water vapour in all latitudinal regions. Data are validated against a set of instruments comprising satellite, ground-based, airborne remote sensing and in-situ instruments. It appears that AMSOS profiles have a dry bias of 3–20%, when compared to satellite experiments. A good agreement with a difference of 3.3% was found between AMSOS and in-situ hygrosondes FISH and FLASH and an excellent matching of the lidar measurements from the DIAL instrument in the short overlap region in the upper troposphere.

Download Full-text

H216O and HDO measurements with IASI/MetOp

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-9267-2009 ◽

2009 ◽

Vol 9 (2) ◽

pp. 9267-9290 ◽

Cited By ~ 10

Author(s):

H. Herbin ◽

D. Hurtmans ◽

C. Clerbaux ◽

L. Clarisse ◽

P.-F. Coheur

Keyword(s):

Water Vapour ◽

Estimation Method ◽

Optimal Estimation ◽

Temporal Variations ◽

Radiative Transfer Model ◽

Transfer Model ◽

Inversion Procedure ◽

Spatio Temporal ◽

The Vertical Distribution

Abstract. In this paper we analyze distributions of water vapour isotopologues in the troposphere using infrared spectra recorded by the Infrared Atmospheric Sounding Interferometer (IASI), which operates onboard the Metop satellite in nadir geometry. The simultaneous uncorrelated retrieval of H216O and HDO was performed on radiance measurements using a line-by-line radiative transfer model and an inversion procedure based on the Optimal Estimation Method (OEM). The characterizations of the retrieved products in terms of vertical sensitivity and error budgets show that IASI measurements contain up to 6 independent pieces of information on the vertical distribution of H216O and up to 3.5 for HDO from the surface up to the upper troposphere (0–20 km). The H216O retrieved profiles are in good agreement with local sonde measurements at different latitudes during different times of the year. Our results demonstrate the ability of the IASI instrument to monitor atmospheric isotopologic water vapour distributions with unprecedented sensitivity. As a case study, we analyse concentration distributions and spatio-temporal variations of H216O and HDO during the October 2007 Krosa super-typhoon over South-East Asia and show with this example the IASI potential to capture variations in the HDO/H216O isotopologic ratio values over space and time.

Download Full-text

Five years of CO, HCN, C2H6, C2H2, CH3OH, HCOOH, and H2CO total columns measured in the Canadian High Arctic

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-11345-2013 ◽

2013 ◽

Vol 6 (6) ◽

pp. 11345-11403

Author(s):

C. Viatte ◽

K. Strong ◽

K. A. Walker ◽

J. R. Drummond

Keyword(s):

Fourier Transform ◽

Biomass Burning ◽

Atmospheric Chemistry ◽

A Priori ◽

Estimation Method ◽

Correlation Coefficients ◽

Optimal Estimation ◽

High Arctic ◽

Retrieval Algorithm ◽

Atmospheric Variability

Abstract. We present a five-year timeseries of seven tropospheric species measured using a ground-based Fourier Transform InfraRed (FTIR) spectrometer at the Polar Environment Atmospheric Research Laboratory (PEARL, Eureka, Nunavut, Canada, 80°05' N, 86°42' W) from 2007 to 2011. Total columns and temporal variabilities of carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C2H6), as well as the first derived total columns at Eureka of acetylene (C2H2), methanol (CH3OH), formic acid (HCOOH), and formaldehyde (H2CO) are investigated, providing a new dataset in the sparsely sampled high latitudes. Total columns are obtained using the SFIT2 retrieval algorithm based on the Optimal Estimation Method. The microwindows, as well as the a priori profiles and variabilities are selected to optimize the information content of the retrievals, and error analyses are performed for all seven species. Our retrievals show good sensitivities in the troposphere. The seasonal amplitudes of the timeseries, ranging from 34 to 104%, are captured while using a single a priori profile for each species. The timeseries of the CO, C2H6 and C2H2 total columns at PEARL exhibit strong seasonal cycles with maxima in winter and minima in summer, in opposite phase to the HCN, CH3OH, HCOOH and H2CO timeseries. These cycles result from the relative contributions of the photochemistry, oxidation, and transport, as well as biogenic and biomass burning emissions. Comparisons of the FTIR partial columns with coincident satellite measurements by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) show good agreement. The correlation coefficients and the slopes range from 0.56 to 0.97, and 0.50 to 3.35, respectively, for the seven target species. Our new dataset is compared with previous measurements found in the literature to assess atmospheric budgets of these tropospheric species in the high Arctic. The CO and C2H6 concentrations are consistent with negative trends observed over the Northern Hemisphere, attributed to fossil fuel emission decrease. The importance of poleward transport on the atmospheric budgets of HCN and C2H2 is highlighted. Columns and variabilities of CH3OH, and HCOOH at PEARL are comparable to previous measurements performed at other remote sites. However, the small columns of H2CO in early May might reflect its large atmospheric variability, and/or the effect of the updated spectroscopic parameters used in our retrievals. Overall, emissions from biomass burning contribute to the day-to-day variabilities of the seven tropospheric species observed at Eureka.

Download Full-text

Retrieval and validation of MetOp/IASI methane