An observed and analysed stratospheric ozone intrusion over the high Canadian Arctic UTLS region during the summer of 2003

Semane, N.; Peuch, Vincent-Henri; Amraoui, L. El; Benchérif, Hassan; Massart, S.; Cariolle, D.; Attié, Jean-Luc; Abida, Rachid

doi:10.1002/qj.141

Cited by 33 publications

(33 citation statements)

References 40 publications

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“…These parameterizations may avoid the impact of misspecified or poorly-known chemical species. By construction, such schemes have no intrinsic trend and then are useful for simulations of several years (e.g., Hadjinicolaou et al, 2005) and data assimilation (e.g., Semane et al, 2007;Massart et al, 2009).…”

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confidence: 99%

A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

et al. 2010

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Abstract. This paper presents an evaluation of a new linear parameterization valid for the troposphere and the stratosphere, based on a first order approximation of the carbon monoxide (CO) continuity equation. This linear scheme (hereinafter noted LINCO) has been implemented in the 3-D Chemical Transport Model (CTM) MOCAGE (MOdèle de Chimie Atmospherique Grande Echelle). First, a one and a half years of LINCO simulation has been compared to output obtained from a detailed chemical scheme output. The mean differences between both schemes are about ±25 ppbv (part per billion by volume) or 15% in the troposphere and ±10 ppbv or 100% in the stratosphere. Second, LINCO has been compared to diverse observations from satellite instruments covering the troposphere (Measurements Of Pollution In The Troposphere: MOPITT) and the stratosphere (Microwave Limb Sounder: MLS) and also from aircraft (Measurements of ozone and water vapour by Airbus in-service aircraft: MOZAIC programme) mostly flying in the upper troposphere and lower stratosphere (UTLS). In the troposphere, the LINCO seasonal variations as well as the vertical and horizontal distributions are quite close to MOPITT CO observations. However, a bias of ∼ −40 ppbv is observed at 700 hPa between LINCO and MOPITT. In the stratosphere, MLS and LINCO present similar large-scale patterns, except over the poles where the CO concentration is underestimated by the model. In the UTLS, LINCO presents small biases Correspondence to: M. Claeyman (marine.claeyman@aero.obs-mip.fr) less than 2% compared to independent MOZAIC profiles. Third, we assimilated MOPITT CO using a variational 3D-FGAT (First Guess at Appropriate Time) method in conjunction with MOCAGE for a long run of one and a half years. The data assimilation greatly improves the vertical CO distribution in the troposphere from 700 to 350 hPa compared to independent MOZAIC profiles. At 146 hPa, the assimilated CO distribution is also improved compared to MLS observations by reducing the bias up to a factor of 2 in the tropics. This study confirms that the linear scheme is able to simulate reasonably well the CO distribution in the troposphere and in the lower stratosphere. Therefore, the low computing cost of the linear scheme opens new perspectives to make free runs and CO data assimilation runs at high resolution and over periods of several years.

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A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

et al. 2010

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“…Hoskins et al (1985) [4] acknowledged the analysis of isentropic potential vorticity (PV) maps as a crucial diagnostic tool for tropopause folds. For instance, a decrease in tropopause height, which is induced by a cyclonic isentropic PV flow anomaly, displaces stratospheric air into the troposphere and an increase in its height, which is induced by an anticyclonic isentropic PV flow anomaly, displaces tropospheric air into the stratosphere [5]. As a consequence, of this "PV thinking", there has been enormously increased interest in using PV for diagnosing cyclogenesis, for research and operational forecasting purposes [6,7].…”

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confidence: 99%

Dynamical contribution of mean potential vorticity pseudo-observations derived from MetOp/GOME2 ozone data into short-range weather forecast during high precipitation events

Sbii

Zazoui

Semane

2015

IJBAS

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Satellites are uniquely capable of providing uniform data coverage globally. Motivated by such capability, this study builds on a previously described methodology that generates numerical weather prediction initial conditions from satellite total column ozone data. The methodology is based on two principal steps. Firstly, the studied linear regression between vertical (100hPa-500hPa) Mean Potential Vorticity (MPV) and MetOp/GOME2 total ozone data (O3) generates MPV pseudo-observations. Secondly, the 3D variational (3D-Var) assimilation method is designed to take into account MPV pseudo-observations in addition to conventional observations. After a successful assimilation of MPV pseudo-observations using a 3D-Var approach within the Moroccan version of the ALADIN limited-area model, the present study aims to assess the dynamical behavior of the short-range forecast at upper levels during heavy precipitation events (HPEs). It is found that MPV assimilation offers the possibility to internally monitor the model upper-level dynamics in addition to the use of Water Vapor Satellite images.

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“…Data assimilation studies that focused on UTLS chemical fields started with Cathala et al (2003), who assimilated subsonic flight-level observations of ozone. Later, Semane et al (2007) assimilated O 3 data from a limb sounder (Michelson Interferometer for Passive Atmospheric Sounding) to diagnose a case study of STE over arctic regions. It has been shown that assimilation of stratospheric ozone data from a limb sounder improves the spatial structure of the ozone fields in the UTLS.…”

Section: Introductionmentioning

confidence: 99%

“…Data assimilation has the capability to overcome possible deficiencies of the MOCAGE model in the UTLS (see, e.g., Semane et al, 2007;Barret et al, 2008;El Amraoui et al, 2010;Barré et al, 2012). The aim of this study is to quantify the impact of the assimilation of O 3 and CO data on the UTLS at extratropical latitudes.…”

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confidence: 99%

Diagnosing the transition layer at extratropical latitudes using MLS O<sub>3</sub> and MOPITT CO analyses

Barré¹,

Amraoui²,

Ricaud³

et al. 2013

Atmos. Chem. Phys.

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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°.

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An observed and analysed stratospheric ozone intrusion over the high Canadian Arctic UTLS region during the summer of 2003

Cited by 33 publications

References 40 publications

A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

Dynamical contribution of mean potential vorticity pseudo-observations derived from MetOp/GOME2 ozone data into short-range weather forecast during high precipitation events

Diagnosing the transition layer at extratropical latitudes using MLS O<sub>3</sub> and MOPITT CO analyses

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An observed and analysed stratospheric ozone intrusion over the high Canadian Arctic UTLS region during the summer of 2003

Cited by 33 publications

References 40 publications

A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

A linear CO chemistry parameterization in a chemistry-transport model: evaluation and application to data assimilation

Dynamical contribution of mean potential vorticity pseudo-observations derived from MetOp/GOME2 ozone data into short-range weather forecast during high precipitation events

Diagnosing the transition layer at extratropical latitudes using MLS O&lt;sub&gt;3&lt;/sub&gt; and MOPITT CO analyses

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Diagnosing the transition layer at extratropical latitudes using MLS O<sub>3</sub> and MOPITT CO analyses