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39 results on '"Lahoz, W.A."'

2. The GCM-Reality Intercomparison Project for SPARC (GRIPS): Scientific Issues and Initial Results

Author

Pawson, S., Kodera, K., Hamilton, K., Shepherd, T.G., Beagley, S.R., Boville, B.A., Farrara, J.D., Fairlie, T.D.A., Kitoh, A., Lahoz, W.A., Langematz, U., Manzini, E., Rind, D.H., Scaife, A.A., Shibata, K., Simon, P., Swinbank, R., Takacs, L., Wilson, R.J., Al-Saadi, J.A., Amodei, M., Chiba, M., Coy, L., Grandpre, J. de, Eckman, R.S., Fiorino, M., Grose, W.L., Koide, H., Koshyk, J.N., Li, D., Lerner, J., Mahlman, J.D., McFarlane, N.A., Mechoso, C.R., Molod, A., O'Neill, A., Pierce, R.B., Randel, W.J., Rood, R.B., and Wu, F.

Subjects
Climatology -- Research, Climatic changes -- Research, Stratosphere -- Environmental aspects, Business, Earth sciences
Abstract

To investigate the effects of the middle atmosphere on climate, the World Climate Research Programme is supporting the project 'Stratospheric Processes and their Role in Climate' (SPARC). A central theme of SPARC, to examine model simulations of the coupled troposphere-middle atmosphere system, is being performed through the initiative called GRIPS (GCM-Reality Intercomparison Project for SPARC). In this paper, an overview of the objectives of GRIPS is given. Initial activities include an assessment of the performance of middle atmosphere climate models, and preliminary results from this evaluation are presented here. It is shown that although all 13 models evaluated represent most major features of the mean atmospheric state, there are deficiencies in the magnitude and location of the features, which cannot easily be traced to the formulation (resolution or the parameterizations included) of the models. Most models show a cold bias in all locations, apart from the tropical tropopause region where they can be either too warm or too cold. The strengths and locations of the major jets are often misrepresented in the models. Looking at three-dimensional fields reveals, for some models, more severe deficiencies in the magnitude and positioning of the dominant structures (such as the Aleutian high in the stratosphere), although undersampling might explain some of these differences from observations. All the models have shortcomings in their simulations of the present-day climate, which might limit the accuracy of predictions of the climate response to ozone change and other anomalous forcing.

Published
2000

3. Stratospheric transport from the tropics to middle latitudes by planetary-wave mixing

Author

Randel, W.J., Gille, J.C., Roche, A.E., Kumer, J.B., Mergenthaler, J.L., Waters, J.W., Fishbein, E.F., and Lahoz, W.A.

Subjects
Stratospheric circulation -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

The Upper Atmosphere Research Satellite yielded ratios of water mixing and nitrous oxide maps which indicated that stratospheric air transport between the tropics and the middle latitude is inhibited by a barrier. Stratospheric material is probably transported to higher latitudes from the tropospheric region due to irreversible mixing of the tongues of air from the tropics into middle latitudes. Filamentation may cause subtropical barrier erosion.

Published
1993

5. Diagnosing the transition layer at extratropical latitudes using MLS O3 and MOPITT CO analyses

Author

Barré, J., El Amraoui, L., Ricaud, P., Lahoz, W.A., Attié, Jean-Luc, Peuch, V.-H., Josse, B., Marécal, V., Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Norsk Institutt for Luftforskning (NILU), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), European Centre for Medium-Range Weather Forecasts (ECMWF), The publication of this articleis financed by CNRS-INSU, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
lcsh:Chemistry, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], lcsh:QD1-999, lcsh:Physics, lcsh:QC1-999
Abstract

The behavior of the extratropical transition layer (ExTL) is investigated using a chemistry transport model (CTM) and analyses derived from assimilation of MLS (Microwave Limb Sounder) O3 and MOPITT (Measurements Of Pollution In The Troposphere) CO data. We firstly focus on a stratosphere–troposphere exchange (STE) case study that occurred on 15 August 2007 over the British Isles (50° N, 10° W). We evaluate the effect of data assimilation on the O3–CO correlations. It is shown that data assimilation disrupts the relationship in the transition region. When MLS O3 is assimilated, CO and O3 values are not consistent between each other, leading to unphysical correlations at the STE location. When MLS O3 and MOPITT CO assimilated fields are taken into account in the diagnostics the relationship happens to be more physical. We then use O3–CO correlations to quantify the effect of data assimilation on the height and depth of the ExTL. When the free-model run O3 and CO fields are used in the diagnostics, the ExTL distribution is found 1.1 km above the thermal tropopause and is 2.6 km wide (2σ). MOPITT CO analyses only slightly sharpen (by −0.02 km) and lower (by −0.2 km) the ExTL distribution. MLS O3 analyses provide an expansion (by +0.9 km) of the ExTL distribution, suggesting a more intense O3 mixing. However, the MLS O3 analyses ExTL distribution shows a maximum close to the thermal tropopause and a mean location closer to the thermal tropopause (+0.45 km). When MLS O3 and MOPITT CO analyses are used together, the ExTL shows a mean location that is the closest to the thermal tropopause (+0.16 km). We also extend the study at the global scale on 15 August 2007 and for the month of August 2007. MOPITT CO analyses still show a narrower chemical transition between stratosphere and troposphere than the free-model run. MLS O3 analyses move the ExTL toward the troposphere and broaden it. When MLS O3 analyses and MOPITT CO analyses are used together, the ExTL matches the thermal tropopause poleward of 50°.

Published
2013

12. A geostationary thermal infrared sensor to monitor the lowermost troposphere: O3 and CO retrieval studies.

Author

Claeyman, M., Attié, J.-L., Peuch, V.-H., El Amraoui, L., Lahoz, W.A., Josse, B., Ricaud, P., Clarmann, T. von, Höpfner, M., Orphal, J., Flaud, J.-M., Edwards, D. P., Chance, K., Liu, X., Pasternak, F., and Cantié, R.

Subjects
AIR quality research, ATMOSPHERIC research, INFRARED detectors, OZONE, CARBON monoxide, SCIENTIFIC apparatus & instruments
Abstract

The article presents a study on the capabilities of a geostationary thermal infrared sensor to monitor ozone and carbon monoxide. It discusses how the analysis was performed by idealized retrieval studies considering typical atmospheric profiles of ozone and carbon monoxide in Europe with various instrument configuration. It also details the results wherein the GEO-TIR configuration showed that it can capture spatial and temporal variability for both ozone and carbon monoxide.

Published
2011
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16. The UARS Microwave Limb Sounder Experiment

Author

Waters, J.W., primary, Barath, F.T., additional, Burke, J.R., additional, Chavez, M.C., additional, Cofield, R.E., additional, Curtis, P.D., additional, Flower, D.A., additional, Fraschetti, T.C., additional, Frerking, M.A., additional, Froidevaux, L., additional, Hardy, J.C., additional, Harris, W.M., additional, Harwood, R.S., additional, Holden, J.R., additional, Jarnot, R.F., additional, Lahoz, W.A., additional, Lau, C.L., additional, Lau, G.K., additional, Lemaster, C.A., additional, Loo, M.S., additional, Maddison, B.F., additional, Matheson, D.N., additional, Natzic, M.J., additional, Oliver, M.B., additional, Parker, D.J., additional, Peckham, G.E., additional, Perun, V.S., additional, Pickett, H.M., additional, Read, W.G., additional, Soltis, F.S., additional, Suttie, R.A., additional, Tarsala, J.A., additional, Voge, C.C., additional, and Wilson, W.J., additional

Published
1990
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17. Three-dimensional evolution of water vapor distributions in the Northern Hemisphere stratosphere...

Author

Lahoz, W.A. and Carr, E.S.

Subjects
*STRATOSPHERE, *ATMOSPHERIC water vapor, *POLAR vortex
Abstract

Analyzes three-dimensional evolution of water vapor distributions in the northern hemisphere stratosphere as observed by the Microwave Limb Sounder (MLS) during the period from October 1991 to July 1992. Vertical and horizontal structure of the northern winter stratosphere; Effects of diabatic descent; Interaction between westerly polar vortex and Aleutian high.

Published
1994
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19. A geostationary thermal infrared sensor to monitor the lowermost troposphere: O₃ and CO retrieval studies

Author

Claeyman, M., Attie, J.L., Peuch, V.H., El Amraoui, L., Lahoz, W.A., Josse, B., Ricaud, P., Clarmann, T. Von, Höpfner, M., Orphal, J., Flaud, J.M., Edwards, D.P., Chance, K., Liu, X., Pasternak, F., and Cantie, R.

Subjects
13. Climate action, 7. Clean energy
Abstract

This paper describes the capabilities of a nadir thermal infrared (TIR) sensor proposed for deployment onboard a geostationary platform to monitor ozone (O3) and carbon monoxide (CO) for air quality (AQ) purposes. To assess the capabilities of this sensor we perform idealized retrieval studies considering typical atmospheric profiles of O3 and CO over Europe with different instrument configuration (signal to noise ratio, SNR, and spectral sampling interval, SSI) using the KOPRA forward model and the KOPRA-fit retrieval scheme. We then select a configuration, referred to as GEO-TIR, optimized for providing information in the lowermost troposphere (LmT; 0–3 km in height). For the GEO-TIR configuration we obtain ~1.5 degrees of freedom for O3 and ~2 for CO at altitudes between 0 and 15 km. The error budget of GEO-TIR, calculated using the principal contributions to the error (namely, temperature, measurement error, smoothing error) shows that information in the LmT can be achieved by GEO-TIR. We also retrieve analogous profiles from another geostationary infrared instrument with SNR and SSI similar to the Meteosat Third Generation Infrared Sounder (MTG-IRS) which is dedicated to numerical weather prediction, referred to as GEO-TIR2. We quantify the added value of GEO-TIR over GEO-TIR2 for a realistic atmosphere, simulated using the chemistry transport model MOCAGE (MOd`ele de Chimie Atmospherique `a Grande Echelle). Results show that GEO-TIR is able to capture well the spatial and temporal variability in the LmT for both O3 and CO. These results also provide evidence of the significant added value in the LmT of GEO-TIR compared to GEO-TIR2 by showing GEO-TIR is closer to MOCAGE than GEO-TIR2 for various statistical parameters (correlation, bias, standard deviation).

22. Toward Improved Estimation of the Dynamic Topography and Ocean Circulation in the High Latitude and Arctic Ocean: The Importance of GOCE

Author

Johannessen, J. A., Raj, R. P., Nilsen, J. E. Ø., Pripp, T., Knudsen, P., Counillon, F., Stammer, D., Bertino, L., Andersen, O. B., Serra, N., Koldunov, N., Bengtsson, Lennart, editor, Bonnet, R.-M., editor, Calisto, M., editor, Destouni, G., editor, Gurney, R., editor, Johannessen, J., editor, Kerr, Y., editor, Lahoz, W.A., editor, and Rast, M., editor

Published
2014
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33. Observing Global Surface Water Flood Dynamics

Author

Bates, Paul D., Neal, Jefferey C., Alsdorf, Douglas, Schumann, Guy J.-P., Bengtsson, Lennart, editor, Bonnet, R.-M., editor, Calisto, M., editor, Destouni, G., editor, Gurney, R., editor, Johannessen, J., editor, Kerr, Y., editor, Lahoz, W.A., editor, and Rast, M., editor

Published
2014
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37. Perspectives in Modelling Climate–Hydrology Interactions

Author

Hagemann, Stefan, Blome, Tanja, Saeed, Fahad, Stacke, Tobias, Bengtsson, Lennart, editor, Bonnet, R.-M., editor, Calisto, M., editor, Destouni, G., editor, Gurney, R., editor, Johannessen, J., editor, Kerr, Y., editor, Lahoz, W.A., editor, and Rast, M., editor

Published
2014
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38. Sea Surface Salinity Observations from Space with the SMOS Satellite: A New Means to Monitor the Marine Branch of the Water Cycle

Author

Reul, Nicolas, Fournier, Severine, Boutin, Jaqueline, Hernandez, Olga, Maes, Christophe, Chapron, Bertrand, Alory, Gaël, Quilfen, Yves, Tenerelli, Joseph, Morisset, Simmon, Kerr, Yann, Mecklenburg, Susanne, Delwart, Steven, Bengtsson, Lennart, editor, Bonnet, R.-M., editor, Calisto, M., editor, Destouni, G., editor, Gurney, R., editor, Johannessen, J., editor, Kerr, Y., editor, Lahoz, W.A., editor, and Rast, M., editor

Published
2014
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