scholarly journals Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC

2012 ◽  
Vol 5 (11) ◽  
pp. 2751-2761 ◽  
Author(s):  
T. Kerzenmacher ◽  
B. Dils ◽  
N. Kumps ◽  
T. Blumenstock ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Atmospheric Composition ◽  
Satellite Measurements ◽  
Solar Absorption ◽  
Mean Values ◽  
Significant Bias ◽  
Ftir Spectrometer ◽  
The Mean ◽  
The Individual ◽  
Total Column

Abstract. Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Université Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from ground-based solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny-Ålesund, Kiruna, Bremen, Jungfraujoch, Izaña and Wollongong. In order to have good statistics for the comparisons, we included all IASI data from the same day, within a 100 km radius around the ground-based stations. The individual ground-based data were adjusted to the lowest altitude of the co-located IASI CO profiles. To account for the different vertical resolutions and sensitivities of the ground-based and satellite measurements, the averaging kernels associated with the various retrieved products have been used to properly smooth coincident data products. It has been found that the IASI CO total column products compare well on average with the co-located ground-based FTIR total columns at the selected NDACC sites and that there is no significant bias for the mean values at all stations.

scholarly journals Validation of IASI FORLI carbon monoxide retrievals using FTIR data from NDACC

2012 ◽  
Vol 5 (3) ◽  
pp. 3973-4002 ◽  
Author(s):  
T. Kerzenmacher ◽  
B. Dils ◽  
N. Kumps ◽  
T. Blumenstock ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Atmospheric Composition ◽  
Satellite Measurements ◽  
Solar Absorption ◽  
Mean Values ◽  
Significant Bias ◽  
Ftir Spectrometer ◽  
The Mean ◽  
The Individual ◽  
Total Column

Abstract. Carbon monoxide (CO) is retrieved daily and globally from space-borne IASI radiance spectra using the Fast Optimal Retrievals on Layers for IASI (FORLI) software developed at the Université Libre de Bruxelles (ULB). The IASI CO total column product for 2008 from the most recent FORLI retrieval version (20100815) is evaluated using correlative CO profile products retrieved from ground-based solar absorption Fourier transform infrared (FTIR) observations at the following FTIR spectrometer sites from the Network for the Detection of Atmospheric Composition Change (NDACC): Ny Ålesund, Kiruna, Bremen, Jungfraujoch, Izaña and Wollongong. In order to have good statistics for the comparisons, we included all IASI data from the same day, within a 100 km radius around the ground-based stations. The individual ground-based data were adjusted to the lowest altitude of the co-located IASI CO profiles. To account for the different vertical resolutions and sensitivities of the ground-based and satellite measurements, the averaging kernels associated with the various retrieved products have been used to properly smooth coincident data products. It has been found that the IASI CO total column products compare well on average with the co-located ground-based FTIR total columns at the selected NDACC sites and that there is no significant bias for the mean values at all stations.

scholarly journals Retrieval of xCO<sub>2</sub> from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON

2016 ◽  
Vol 9 (2) ◽  
pp. 577-585 ◽  
Author(s):  
Matthias Buschmann ◽  
Nicholas M. Deutscher ◽  
Vanessa Sherlock ◽  
Mathias Palm ◽  
Thorsten Warneke ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Seasonal Cycle ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
Composition Change ◽  
Solar Absorption ◽  
Mid Infrared ◽  
Infrared Spectral ◽  
Ftir Spectrometer ◽  
Total Column

Abstract. High-resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change Infrared Working Group (NDACC-IRWG) in the mid-infrared spectral region, are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column-averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier transform infrared (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to colocated standard TCCON (Total Carbon Column Observing Network) measurements of column-averaged dry-air mole fractions of CO2 (denoted by xCO2). Comparing the NDACC and TCCON retrievals, we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of 2) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g., the seasonal cycle) in the column average.

scholarly journals Background CO<sub>2</sub> levels and error analysis from ground-based solar absorption IR measurements in central Mexico

2017 ◽  
Author(s):  
Jorge L. Baylon ◽  
Wolfgang Stremme ◽  
Michel Grutter ◽  
Frank Hase ◽  
Thomas Blumenstock
Keyword(s):  
Total Carbon ◽  
Central Mexico ◽  
Independent Data ◽  
Data Set ◽  
Solar Absorption ◽  
Diurnal Cycles ◽  
Ftir Spectrometer ◽  
The Mean ◽  
Main Component ◽  
Total Column

Abstract. In this investigation we analyze two common optical configurations to retrieve CO2 total column amounts from solar absorption infrared spectra. The noise errors using either a KBr or a CaF2 beamsplitter, a main component of a Fourier transform infrared (FTIR) spectrometer, are quantified in order to assess the relative precisions of the measurements. The configuration using a CaF2 beamsplitter, as deployed by the instruments which contribute to the Total Carbon Column Observing Network (TCCON), shows a slightly better precision. However, we show that the precisions in XCO2 retrieved from > 96 % of the spectra measured with a KBr beamsplitter, fall well below 0.2 %. A small bias in XCO2 (KBr – CaF2) of +0.56 ± 0.25 ppm was found when using an independent data set as reference. This value, which corresponds to +0.14 ± 0.064 %, is slightly larger than the mean precisions obtained and could be taken into account when homogenizing or comparing data from both beamsplitters. A 3-year XCO2 time series from FTIR measurements at the high-altitude site of Altzomoni in central Mexico presents clear annual and diurnal cycles and a trend of +2.2 ppm/yr could be determined.

scholarly journals Retrieval of xCO<sub>2</sub> from ground-based mid-infrared (NDACC) solar absorption spectra and comparison to TCCON

2015 ◽  
Vol 8 (10) ◽  
pp. 10523-10548 ◽  
Author(s):  
M. Buschmann ◽  
N. M. Deutscher ◽  
V. Sherlock ◽  
M. Palm ◽  
T. Warneke ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Seasonal Cycle ◽  
Atmospheric Composition ◽  
Composition Change ◽  
Solar Absorption ◽  
Mid Infrared ◽  
Infra Red ◽  
Infrared Spectral ◽  
Ftir Spectrometer ◽  
Total Column

Abstract. High resolution solar absorption spectra, taken within the Network for the Detection of Atmospheric Composition Change (NDACC) in the mid-infrared spectral region are used to infer partial or total column abundances of many gases. In this paper we present the retrieval of a column averaged mole fraction of carbon dioxide from NDACC-IRWG spectra taken with a Fourier-Transform-Infra-Red (FTIR) spectrometer at the site in Ny-Ålesund, Spitsbergen. The retrieved time series is compared to co-located standard TCCON measurements of total column CO2. Comparing the NDACC and TCCON retrievals we find that the sensitivity of the NDACC retrieval is lower in the troposphere (by a factor of two) and higher in the stratosphere, compared to TCCON. Thus, the NDACC retrieval is less sensitive to tropospheric changes (e.g. the seasonal cycle) in the column average.

Comparison of Emission Levels of Motor Cars, Motorcycles, and Tricycles Using Petrol Engines in Southwestern Nigeria

2021 ◽  
Vol 900 ◽  
pp. 183-187
Author(s):  
Odunlami Olayemi Abosede ◽  
Akeredolu Funso Alaba
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Carbon Dioxide Emissions ◽  
Mean Value ◽  
Southwestern Nigeria ◽  
Mean Values ◽  
Mobile Sources ◽  
Southwest Nigeria ◽  
The Mean ◽  
European Standards

The emissions of carbon monoxide, carbon dioxide, and hydrocarbon from four stroke-powered motorcars and two stroke-powered motorcycles and tricycles in Southwest Nigeria were examined using an automotive 4-gas analyer. Results show that tricycles produced more hydrocarbon and carbon monoxide emissions than motorcycles, while motorcycles emitted more of these pollutants than the gasoline fueled motor cars. (The gasoline fueled motorcars produced lowest hydrocarbon and carbon monoxide while the tricycles produced the highest hydrocarbon and carbon monoxide emissions). On the contrary, motor cars had the highest mean value of carbon dioxide followed by the motorcycles, while tricycles had the least. This could be attributed to the presence of the catalytic converters in some of the motor cars oxidizing carbon monoxide to carbon dioxide. The mean values of hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcars are 630ppm, 10200ppm and 59900ppm. This is much higher than the NESREA (National Environmental standards and Regulations Enforcement Agency) standards as well as Euro II and Euro III (European standards) for vehicular emission. The mean values for hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcycles and tricycles are (2150ppm, 21530ppm and 31200ppm) and (2820ppm, 24880ppm and 38710ppm) respectively. These results do not comply with Nigeria and European emission standards for hydrocarbon, and carbon monoxide. Tricycles and motorcycles account for higher concentrations of hydrocarbon and carbon monoxide pollutants from mobile sources, while they emit carbon dioxide minimally.

scholarly journals Ground-based Measurements of Atmospheric Trace Gases in Beijing during the Olympic Games

Sci ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 6
Author(s):  
Jie Cheng
Keyword(s):  
Olympic Games ◽  
Trace Gases ◽  
Fourier Transform Spectrometer ◽  
Atmospheric Trace Gases ◽  
Validation Data ◽  
Solar Absorption ◽  
The Mean ◽  
The City ◽  
Total Column ◽  
The Olympic Games

A portable Fourier Transform Spectrometer (B3M-IR) is built and used to measure atmospheric trace gases in the city of Beijing during Olympic Games in 2008. A short description of the instrument is first provided in this paper. A detailed spectral analysis is then presented. The total columns of ozone (O3), carbon monoxide (CO), methane (CH4) and nitrous oxide (N2O) are retrieved from the ground-based solar absorption spectra recorded by the B3M-IR during the Olympic Games. Lacking validation data, only the retrieved total column of O3 is compared with that retrieved by MAX-DOAS, which is deployed at the same station. The mean difference between the two methods of measurement is 6.5%, demonstrating the performance and reliability of B3M-IR.

scholarly journals Effects of food and sucralfate on a single oral dose of 500 milligrams of levofloxacin in healthy subjects.

1997 ◽  
Vol 41 (10) ◽  
pp. 2196-2200 ◽  
Author(s):  
L J Lee ◽  
B Hafkin ◽  
I D Lee ◽  
J Hoh ◽  
R Dix
Keyword(s):  
Oral Dose ◽  
Healthy Subjects ◽  
High Fat ◽  
Time Curve ◽  
Mean Values ◽  
Treatment Groups ◽  
The Mean ◽  
The Individual ◽  
Individual Profiles ◽  
Fat Meal

The effects of food and sucralfate on the pharmacokinetics of levofloxacin following the administration of a single 500-mg oral dose were investigated in a randomized, three-way crossover study with young healthy subjects (12 males and 12 females). Levofloxacin was administered under three conditions: fasting, fed (immediately after a standardized high-fat breakfast), and fasting with sucralfate given 2 h following the administration of levofloxacin. The concentrations of levofloxacin in plasma and urine were determined by high-pressure liquid chromatography. By noncompartmental methods, the maximum concentration of drug in serum (Cmax), the time to Cmax (Tmax), the area under the concentration-time curve (AUC), half-life (t1/2), clearance (CL/F), renal clearance (CLR), and cumulative amount of levofloxacin in urine (Ae) were estimated. The individual profiles of the drug concentration in plasma showed little difference among the three treatments. The only consistent effect of the coadministration of levofloxacin with a high-fat meal for most subjects was that levofloxacin absorption was delayed and Cmax was slightly reduced (Tmax, 1.0 and 2.0 h for fasting and fed conditions, respectively [P = 0.002]; Cmax, 5.9 +/- 1.3 and 5.1 +/- 0.9 microg/ml [90% confidence interval = 0.79 to 0.94] for fasting and fed conditions, respectively). Sucralfate, which was administered 2 h after the administration of levofloxacin, appeared to have no effect on levofloxacin's disposition compared with that under the fasting condition. Mean values of Cmax and AUC from time zero to infinity were 6.7 +/- 3.2 microg/ml and 47.9 +/- 8.4 microg x h/ml, respectively, following the administration of sucralfate compared to values of 5.9 +/- 1.3 microg/ml and 50.5 +/- 8.1 microg x h/ml, respectively, under fasting conditions. The mean t1/2, CL/F, CLR, and Ae values were similar among all three treatment groups. In conclusion, the absorption of levofloxacin was slightly delayed by food, although the overall bioavailability of levofloxacin following a high-fat meal was not altered. Finally, sucralfate did not alter the disposition of levofloxacin when sucralfate was given 2 h after the administration of the antibacterial agent, thus preventing a potential drug-drug interaction.

scholarly journals Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space

2012 ◽  
Vol 12 (11) ◽  
pp. 29915-29965 ◽  
Author(s):  
W. Stremme ◽  
M. Grutter ◽  
C. Rivera ◽  
A. Bezanilla ◽  
A. R. Garcia ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Spatial Distribution ◽  
Mexico City ◽  
Emission Flux ◽  
Top Down ◽  
Solar Absorption ◽  
Surface Emission ◽  
The Difference ◽  
Anthropogenic Pollutant ◽  
Total Column

Abstract. Continuous carbon monoxide (CO) total column densities above the UNAM campus in Mexico City have been derived from solar absorption infrared spectroscopic measurements since October 2007. Its diurnal evolution is used in the present study in conjunction with other ground-based and satellite data to develop a top-down emission estimate of the annual CO emission of the Mexico City Metropolitan Area (MCMA). The growth-rate of the total column around noon under low ventilation conditions is calculated and allows us to derive the average surface emission-flux at UNAM, while similar measurements taken at the edge of the MCMA in Tecámac provides information on background CO levels in the Mexico basin. Based on 3 yr of measurements, CO column measurements from the IASI satellite instrument are used to reconstruct the spatial distribution of this anthropogenic pollutant over the MCMA. The agreement between the measured columns of the satellite and ground-based measurements is excellent, particularly when a comparison strategy based on time-displaced air masses is used. The annual emission of the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr−1 for the year 2008, while the official inventory for that year reported 1.6 Tg yr−1. The difference is slightly higher than the conservative uncertainty estimated in this work suggesting that the emission might be underestimated by the conventional bottom-up method. A larger discrepancy is found in the spatial distribution of the emissions, when comparing the emission flux over UNAM (derived from the ground-based measurement) with that of the inventory integrated over a representative area. The methodology presented here represents a new and useful strategy to evaluate the contribution of megacities to the global anthropogenic gas emissions. Additionally, three different strategies to compare ground and space-based measurements above an inhomogeneous and strongly contaminated area like Mexico City are presented and discussed.

scholarly journals Genetic homozygosity as a marker of smoking dependency

Genetika ◽  
2020 ◽  
Vol 52 (3) ◽  
pp. 1009-1019
Author(s):  
Slavko Brankovic ◽  
Dejan Nikolic ◽  
Dragoslav Marinkovic ◽  
Suzana Cvjeticanin
Keyword(s):  
Cross Sectional Study ◽  
Male Gender ◽  
Sectional Study ◽  
Cross Sectional ◽  
Male And Female ◽  
Mean Values ◽  
Individual Variations ◽  
Significant Difference ◽  
The Mean ◽  
The Individual

The aim of our study was to evaluate the morphogenetic variability as a marker of smoking dependency in adult smokers versus controls and to investigate the presence and the degree of morphogenetic variability difference between male and female smokers versus same gender controls. The cross-sectional study evaluated 241 smokers and 185 nonsmoker individuals as controls. We analyzed 17 homozygous recessive characteristics (HRC). There was a significant difference in the individual variations of 17 HRCs between the controls and smokers (??2=61.400, p<0.001; for females ??2=79.440, p<0.001; for males ??2=84.972, p<0.001). The mean values of HRCs significantly differed between smokers and controls (MV?SEM(Controls) -4.79?0.13, MV?SEM(Smokers) -5.70?0.12; p<0.001). For males, presence of 6/17 (35.29% genetic homozygosity) HRCs (OR=6.12) was to the certain degree predictor for smoking dependency. Higher degree of genetic homozygosity, changed variability and male gender, might be some among potential numerous factors that could have impact on smoking development and dependence.

scholarly journals On phenomena relating to the spectra of hydrogen and helium

1916 ◽  
Vol 93 (646) ◽  
pp. 27-28
Keyword(s):  
Accurate Determination ◽  
Principal Series ◽  
Black Body ◽  
Black Body Radiation ◽  
Balmer Series ◽  
Mean Values ◽  
Carbon Arc ◽  
The Mean ◽  
The Individual

In a previous paper the structure of broadened spectrum lines was investigated by a method involving the use of a neutral-tinted wedge as an accessory to the spectroscope. The present communication deals with a method for the accurate determination of the photographic intensities of spectrum lines and the reduction of such intensities to absolute values by comparison with the continuous black-body radiation of the carbon arc. These methods have been applied to a study of the relative intensity distribution in the spectra of helium and hydrogen under different conditions of excitation. It has been found that under certain specified conditions there is a transfer of energy from the longer to the shorter wave-lengths in any given series, and that, under such conditions, the associated series, and in particular the Diffuse series, are relatively enhanced at the expense of the Principal series. It has also been found that the distribution of intensity found in certain celestial spectra can be approximately reproduced in the laboratory. In any attempt to interpret the phenomena observed in connection with the Balmer series of hydrogen, it is necessary to know the particular type to which this series belongs. In order to decide this point a study has been made of the separations of the components of lines of the Balmer series of hydrogen, and the mean values of the separations of the doublets constituting the lines H a and H β have been found to be respectively 0.132 Å.U. and 0.033 Å.U. These values are consistent with the separations appropriate to a Principal series, and the first is in precise agreement with the value deduced by Buisson and Fabry. These results have been obtained by crossing a Lummer Gehrcke plate with the neutral wedge, and submitting the contours obtained to mathematical analysis, by means of which the distribution of intensity in the individual components, and the separation of the components, can be determined.

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