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Matthias Beekmann - One of the best experts on this subject based on the ideXlab platform.
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tropospheric ozone distributions over europe during the heat wave in july 2007 observed from infrared nadir spectra recorded by iasi
Geophysical Research Letters, 2008Co-Authors: Maxim Eremenko, Matthias Beekmann, Gaelle Dufour, Gilles Foret, C Keim, J Orphal, G Bergametti, J M FlaudAbstract:[1] First partial tropospheric ozone columns (0–6 km) derived from radiances observed by the IASI instrument aboard the MetOp-A platform over Europe during summer 2007 are presented. They were retrieved using an altitude-dependent regularization method. Comparison with measurements from balloon Sondes shows excellent agreement. Space-borne observations show large lower tropospheric ozone amounts over South-Eastern Europe during the heat wave period, which are also displayed by simulations with a regional chemistry-transport model CHIMERE.
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tropospheric ozone distributions over europe during the heat wave in july 2007 observed from infrared nadir spectra recorded by iasi
Geophysical Research Letters, 2008Co-Authors: Maxim Eremenko, Matthias Beekmann, Gaelle Dufour, Gilles Foret, C Keim, J Orphal, G Bergametti, J M FlaudAbstract:[1] First partial tropospheric ozone columns (0–6 km) derived from radiances observed by the IASI instrument aboard the MetOp-A platform over Europe during summer 2007 are presented. They were retrieved using an altitude-dependent regularization method. Comparison with measurements from balloon Sondes shows excellent agreement. Space-borne observations show large lower tropospheric ozone amounts over South-Eastern Europe during the heat wave period, which are also displayed by simulations with a regional chemistry-transport model CHIMERE.
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intercomparison of tropospheric ozone profiles obtained by electrochemical Sondes a ground based lidar and an airborne uv photometer
Atmospheric Environment, 1995Co-Authors: Matthias Beekmann, Gerard Ancellet, D Martin, C Abonnel, G Duverneuil, F Eideliman, P Bessemoulin, N Fritz, E GizardAbstract:Abstract Eight simultaneous tropospheric ozone profiles have been recorded during an intercomparison campaign at Observatoire de Haute Provence in Southern France from 23 March 1991 to 3 April 1991. The participating instruments were electrochemical Sondes of ECC type (Meteo France, CNRM/GMEI), of Brewer-Mast type (Service d'Aeronomie, CNRS), a ground-based UV-DIAL lidar (Service d'Aeronomie, CNRS) and an airborne UV-photometer (Meteo France, CNRM/CAM). Averaged over a 4.5–8 km height range, the biases derived with respect to the median ozone concentration of the four instruments are + 25 ± 3% for ECC Sondes, −1 ± 3% for Brewer-Mast Sondes, − 3 ± 2% for the airborne UV-photometer and − 7 ± 2% for the lidar. Applying the Dobson normalisation to ECC Sondes, its bias is reduced to + 18%, part of which (up to 7%) may be explained by an incorrect estimation of the background current evolution following the standard procedure recommended for ECC Sondes (Vaisala, OES 11 Ozonesonde User's Guide, 1988). The precision derived from the results of this campaign is 10% for ECC Sondes, 9% for Brewer-Mast Sondes, 5% for the UV-photometer and 5% for the lidar in the troposphere. These results are compared to that of previous intercomparison campaigns and discussed with respect to possible measurement errors related to the different instruments.
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Intercomparison campaign of vertical ozone profiles including electrochemical Sondes of ECC and Brewer-Mast type and a ground based UV-differential absorption lidar
Journal of Atmospheric Chemistry, 1994Co-Authors: Matthias Beekmann, Gerard Ancellet, G. Mégie, H. G. J. Smit, D. KleyAbstract:An intercomparison campaign was conducted at the Observatoire de Haute Provence (OHP) in Southern France in September 1989 in order to compare the three instruments used for vertical tropospheric ozone profiling in the European TOR (Tropospheric Ozone Research Project) network: balloon borne ECC and Brewer-Mast Sondes and a ground based UV-DIAL ( D ifferential A bsorption L idar). Additionally, a stratospheric lidar system and the Dobson spectrophotometer of the OHP were operated. Seven simultaneously measured vertical ozone profiles gave evidence for systematic differences of 15% between both types of electrochemical Sondes in the troposphere, the Brewer-Mast Sondes reading the smaller ozone values. These differences might be explained on the one hand by a possible contamination of the ozone sensor with reducing substances, causing a negative bias mainly for Brewer-Mast Sondes and, on the other hand, by the evolution of the sonde background current during the flight, causing a positive bias for ECC Sondes and a negative bias for Brewer-Mast Sondes. The tropospheric lidar system, measuring the vertical ozone distribution between 6 and 12–15 km, showed ozone concentrations intermediate between the sonde results. This is in good agreement with its estimated systematic error of better than 7% in the upper troposphere. In the stratosphere, the differences between electrochemical Sondes and the lidar are between 5 and 10% before the normalisation with the total ozone values measured by the Dobson spectrophotometer, and always below 5% after. While the Dobson normalisation thus corrects rather well the stratospheric part of the sonde profile, it only partially reduces errors occurring in the troposphere.
David W. Tarasick - One of the best experts on this subject based on the ideXlab platform.
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a multi sensor upper tropospheric ozone product mutop based on tes ozone and goes water vapor validation with ozoneSondes
Atmospheric Chemistry and Physics, 2011Co-Authors: J L Moody, Anne M Thompson, G B Osterman, S R Felker, Anthony J Wimmers, David W. TarasickAbstract:Abstract. Accurate representation of ozone in the extratropical upper troposphere (UT) remains a challenge. However, the implementation of hyper-spectral remote sensing using satellite instruments such as the Tropospheric Emission Spectrometer (TES) provides an avenue for mapping ozone in this region, from 500 to 300 hPa. As a polar orbiting satellite TES observations are limited, but in this paper they are combined with geostationary satellite observations of water vapor. This paper describes a validation of the Multi-sensor UT Ozone Product (MUTOP). MUTOP, based on a statistical retrieval method, is an image product derived from the multiple regression of remotely sensed TES ozone, against geostationary (GOES) specific humidity (remotely sensed) and potential vorticity (a modeled dynamical tracer in the UT). These TES-derived UT ozone mixing ratios are compared to coincident ozonesonde measurements of layer-average UT ozone mixing ratios made during the NASA INTEX/B field campaign in the spring of 2006; the region for this study is effectively the GOES west domain covering the eastern North Pacific Ocean and the western United States. This intercomparison evaluates MUTOP skill at representing ozone magnitude and variability in this region of complex dynamics. In total, 11 ozonesonde launch sites were available for this study, providing 127 individual Sondes for comparison; the overall mean ozone of the 500–300 hPa layer for these Sondes was 78.0 ppbv. MUTOP reproduces in~situ measurements reasonably well, producing an UT mean of 82.3 ppbv, with a mean absolute error of 12.2 ppbv and a root mean square error of 16.4 ppbv relative to ozoneSondes across all sites. An overall UT mean bias of 4.3 ppbv relative to Sondes was determined for MUTOP. Considered in the context of past TES validation studies, these results illustrate that MUTOP is able to maintain accuracy similar to TES while expanding coverage to the entire GOES-West satellite domain. In addition MUTOP provides six-hour temporal resolution throughout the INTEX-B study period, making the visualization of UT ozone dynamics possible. This paper presents the overall statistical validation as well as a selection of ozonesonde case studies. The case studies illustrate that error may not always represent a lack of TES-derived product skill, but often results from discrepancies driven by observations made in the presence of strong meteorological gradients.
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assessment of the performance of ecc ozoneSondes under quasi flight conditions in the environmental simulation chamber insights from the juelich ozone sonde intercomparison experiment josie
Journal of Geophysical Research, 2007Co-Authors: Herman G J Smit, David W. Tarasick, R. Stübi, Samuel J. Oltmans, J Davies, Wolfgang Straeter, Bryan J Johnson, Bruno Hoegger, Francis J Schmidlin, T NorthamAbstract:[1] Since 1996, quality assurance experiments of electrochemical concentration cell (ECC) ozoneSondes of two different model types (SPC-6A and ENSCI-Z) have been conducted in the environmental simulation facility at the Research Centre Juelich within the framework of the Juelich Ozone Sonde Intercomparison Experiment (JOSIE). The experiments have shown that the performance characteristics of the two ECC-sonde types can be significantly different, even when operated under the same conditions. Particularly above 20 km the ENSCI-Z sonde tends to measure 5–10% more ozone than the SPC-6A sonde. Below 20 km the differences are 5% or less, but appear to show some differences with year of manufacture. There is a significant difference in the ozone readings when Sondes of the same type are operated with different cathode sensing solutions. Testing the most commonly used sensing solutions showed that for each ECC-manufacturer type the use of 1.0% KI and full buffer gives 5% larger ozone values compared with the use of 0.5% KI and half buffer, and as much as 10% larger values compared with 2.0% KI and no buffer. For ozone sounding stations performing long term measurements this means that changing the sensing solution type or ECC-sonde type can easily introduce a change of ±5% or more in their records, affecting determination of ozone trends. Standardization of operating procedures for ECC-Sondes yields a precision better than ±(3–5)% and an accuracy of about ±(5–10)% up to 30 km altitude.
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laboratory investigations of the response of brewer mast ozoneSondes to tropospheric ozone
Journal of Geophysical Research, 2002Co-Authors: David W. Tarasick, J Davies, K G Anlauf, Maurice Watt, W Steinbrecht, H ClaudeAbstract:[1] The Brewer-Mast ozonesonde was used at Canadian stations from 1966 until 1980, when the Canadian network switched to the electrochemical concentration cell sonde. While the Sondes appear to agree relatively well in the stratosphere, there is an evident discrepancy of 10–20% in tropospheric measurements [e.g., Tarasick et al., 1995, Figure 4]. Comparison of Brewer-Mast Sondes with a calibrated ozone source yields some interesting insight into this discrepancy. Sonde response is strongly dependent on the preflight preparation procedures employed. Although Sondes prepared via procedures introduced in the 1980s [Claude et al., 1987] perform quite well, when prepared according to the procedures used in Canada in the 1970s, Brewer-Mast Sondes indicate 10–30% lower ozone than the calibrator. The following points are noted in particular: (1) a new Brewer-Mast sonde shows a large (∼15%) increase in sensitivity between successive experiments; (2) especially at low (<100 ppb) O3 levels, the response even of previously flown Sondes increases slowly with time; and (3) Sondes show an additional slow increase of response with time that is apparently caused by ozone reactions with the phosphate buffer. The overall response curve indicated by 1, 2, and 3 implies that after correction to the observed total ozone, the earlier part of a flight would yield values that are too low, while the latter part would be too high. By applying a varying ozone input, simulating the typical variation in absolute ozone concentration experienced by a sonde in flight, we show that this can explain both the average correction factor (1.255) for the Canadian Brewer-Mast record and the 10–20% discrepancy in tropospheric measurements.
D F Hurst - One of the best experts on this subject based on the ideXlab platform.
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comparisons of temperature pressure and humidity measurements by balloon borne radioSondes and frost point hygrometers during mohave 2009
Atmospheric Measurement Techniques, 2011Co-Authors: D F Hurst, Emrys G Hall, Allen Jordan, Larry M Miloshevich, David N Whiteman, Thierry Leblanc, D WalshAbstract:Abstract. We compare coincident, in situ, balloon-borne measurements of temperature (T) and pressure (P) by two radioSondes (Vaisala RS92, Intermet iMet-1-RSB) and similar measurements of relative humidity (RH) by RS92 Sondes and frost point hygrometers. Data from a total of 28 balloon flights with at least one pair of radioSondes are analyzed in 1-km altitude bins to quantify measurement differences between the sonde sensors and how they vary with altitude. Each comparison (T, P, RH) exposes several profiles of anomalously large measurement differences. Measurement difference statistics, calculated with and without the anomalous profiles, are compared to uncertainties quoted by the radiosonde manufacturers. Excluding seven anomalous profiles, T differences between 19 pairs of RS92 and iMet Sondes exceed their measurement uncertainty limits (2 σ) 31% of the time and reveal a statistically significant, altitude-independent bias of 0.5 ± 0.2 °C. Similarly, RS92-iMet P differences in 22 non-anomalous profiles exceed their uncertainty limits 23% of the time, with a disproportionate 83% of the excessive P differences at altitudes >16 km. The RS92-iMet pressure differences increase smoothly from −0.6 hPa near the surface to 0.8 hPa above 25 km. Temperature and P differences between all 14 pairs of RS92 Sondes exceed manufacturer-quoted, reproducibility limits (σ) 28% and 11% of the time, respectively. About 95% of the excessive T differences are eliminated when 5 anomalous RS92-RS92 profiles are excluded. Only 5% of RH measurement differences between 14 pairs of RS92 Sondes exceed the manufacturer's measurement reproducibility limit (σ). RH measurements by RS92 Sondes are also compared to RH values calculated from frost point hygrometer measurements and coincident T measurements by the radioSondes. The influences of RS92-iMet Tand P differences on RH values and water vapor mixing ratios calculated from frost point hygrometer measurements are examined.
J M Flaud - One of the best experts on this subject based on the ideXlab platform.
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tropospheric ozone distributions over europe during the heat wave in july 2007 observed from infrared nadir spectra recorded by iasi
Geophysical Research Letters, 2008Co-Authors: Maxim Eremenko, Matthias Beekmann, Gaelle Dufour, Gilles Foret, C Keim, J Orphal, G Bergametti, J M FlaudAbstract:[1] First partial tropospheric ozone columns (0–6 km) derived from radiances observed by the IASI instrument aboard the MetOp-A platform over Europe during summer 2007 are presented. They were retrieved using an altitude-dependent regularization method. Comparison with measurements from balloon Sondes shows excellent agreement. Space-borne observations show large lower tropospheric ozone amounts over South-Eastern Europe during the heat wave period, which are also displayed by simulations with a regional chemistry-transport model CHIMERE.
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tropospheric ozone distributions over europe during the heat wave in july 2007 observed from infrared nadir spectra recorded by iasi
Geophysical Research Letters, 2008Co-Authors: Maxim Eremenko, Matthias Beekmann, Gaelle Dufour, Gilles Foret, C Keim, J Orphal, G Bergametti, J M FlaudAbstract:[1] First partial tropospheric ozone columns (0–6 km) derived from radiances observed by the IASI instrument aboard the MetOp-A platform over Europe during summer 2007 are presented. They were retrieved using an altitude-dependent regularization method. Comparison with measurements from balloon Sondes shows excellent agreement. Space-borne observations show large lower tropospheric ozone amounts over South-Eastern Europe during the heat wave period, which are also displayed by simulations with a regional chemistry-transport model CHIMERE.
T Gierczak - One of the best experts on this subject based on the ideXlab platform.
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laboratory evaluation of the effect of nitric acid uptake on frost point hygrometer performance
Atmospheric Measurement Techniques, 2010Co-Authors: Troy Thornberry, T Gierczak, R S Gao, H Vomel, L A Watts, James B BurkholderAbstract:Abstract. Chilled mirror hygrometers (CMH) are widely used to measure water vapour in the troposphere and lower stratosphere from balloon-borne Sondes. Systematic discrepancies among in situ water vapour instruments have been observed at low water vapour mixing ratios ( 10%) in surface reflectivity by the condensate to determine H2O.
