Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

Emili, Emanuele; Barret, Brice; Massart, S.; Flochmoën, É. Le; Piacentini, Andrea; Amraoui, L. El; Pannekoucke, Olivier; Cariolle, D.

doi:10.5194/acp-14-177-2014

Cited by 44 publications

(107 citation statements)

References 71 publications

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“…As in Emili et al (2014), the background standard deviation 3-D field is parameterized as a vertically varying percentage of the background profile, which decreases from values of 25 % at the surface to values of 15 % in the upper troposphere and decreases further throughout the stratosphere to values of 5 % in the upper stratosphere (not shown). We base these settings on several 1-day assimilation trials; they ensure reasonable values of standard self-consistency tests, e.g., providing chi-squared (χ 2 ) values close to 1 (see Fig.…”

Section: The Assimilation Runmentioning

confidence: 99%

Impact of spaceborne carbon monoxide observations from the S-5P platform on tropospheric composition analyses and forecasts

Abida¹,

Attié

Amraoui³

et al. 2017

Atmos. Chem. Phys.

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Abstract. We use the technique of Observing System Simulation Experiments (OSSEs) to quantify the impact of spaceborne carbon monoxide (CO) total column observations from the Sentinel-5 Precursor (S-5P) platform on tropospheric analyses and forecasts. We focus on Europe for the period of northern summer 2003, when there was a severe heat wave episode associated with extremely hot and dry weather conditions. We describe different elements of the OSSE: (i) the nature run (NR), i.e., the "truth"; (ii) the CO synthetic observations; (iii) the assimilation run (AR), where we assimilate the observations of interest; (iv) the control run (CR), in this study a free model run without assimilation; and (v) efforts to establish the fidelity of the OSSE results. Comparison of the results from AR and the CR, against the NR, shows that CO total column observations from S-5P provide a significant benefit (at the 99 % confidence level) at the surface, with the largest benefit occurring over land in regions far away from emission sources. Furthermore, the S-5P CO total column observations are able to capture phenomena such as the forest fires that occurred in Portugal during northern summer 2003. These results provide evidence of the benefit of S-5P observations for monitoring processes contributing to atmospheric pollution.

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Section: The Assimilation Runmentioning

confidence: 99%

Impact of spaceborne carbon monoxide observations from the S-5P platform on tropospheric composition analyses and forecasts

Abida¹,

Attié

Amraoui³

et al. 2017

Atmos. Chem. Phys.

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“…All the profiles are sampled to 1 km layers in the radiative transfer calculations. As the MOCAGE model top is set at 35 km altitude, we complete the atmospheric vertical information between 30 and 50 km with data from a global MOCAGE simulation, run at coarser resolution with model top at 0.1 hPa (Emili et al, 2014) and with climatological profiles above 50 km.…”

Section: Nature Run and Pseudo-observation Simulatormentioning

confidence: 99%

Potential of multispectral synergism for observing ozone pollution by combining IASI-NG and UVNS measurements from the EPS-SG satellite

et al. 2017

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Abstract. Present and future satellite observations offer great potential for monitoring air quality on a daily and global basis. However, measurements from currently orbiting satellites do not allow a single sensor to accurately probe surface concentrations of gaseous pollutants such as tropospheric ozone. Combining information from IASI (Infrared Atmospheric Sounding Interferometer) and GOME-2 (Global Ozone Monitoring Experiment-2) respectively in the TIR and UV spectra, a recent multispectral method (referred to as IASI+GOME-2) has shown enhanced sensitivity for probing ozone in the lowermost troposphere (LMT, below 3 km altitude) with maximum sensitivity down to 2.20 km a.s.l. over land, while sensitivity for IASI or GOME-2 alone only peaks at 3 to 4 km at the lowest.In this work we develop a pseudo-observation simulator and evaluate the potential of future EPS-SG (EUMET-SAT Polar System -Second Generation) satellite observations, from new-generation sensors IASI-NG (Infrared Atmospheric Sounding Interferometer -New Generation) and UVNS (Ultraviolet Visible Near-infrared Shortwaveinfrared), to observe near-surface O 3 through the IASI-NG+UVNS multispectral method. The pseudo-real state of the atmosphere is provided by the MOCAGE (MOdèle de Chimie Atmosphérique à Grande Échelle) chemical transport model. We perform full and accurate forward and inverse radiative transfer calculations for a period of 4 days (8-11 July 2010) over Europe.In the LMT, there is a remarkable agreement in the geographical distribution of O 3 partial columns between IASI-NG+UVNS pseudo-observations and the corresponding MOCAGE pseudo-reality. With respect to synthetic IASI+GOME-2 products, IASI-NG+UVNS shows a higher correlation between pseudo-observations and pseudo-reality, which is enhanced by about 12 %. The bias on high ozone retrieval is reduced and the average accuracy increases by 22 %. The sensitivity to LMT ozone is also enhanced. On average, the degree of freedom for signal is higher by 159 % over land (from 0.29 to 0.75) and 214 % over ocean (from 0.21 to 0.66). The mean height of maximum sensitivity for the LMT peaks at 1.43 km over land and 2.02 km over ocean, respectively 1.03 and 1.30 km below that of IASI+GOME-2. IASI-NG+UVNS also shows good retrieval skill in the surface-2 km altitude range. It is one of a kind for retrieving ozone layers of 2-3 km thickness, in the first 2-3 km of the atmosphere. IASI-NG+UVNS is expected to largely enhance the capacity to observe ozone pollution from space.

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“…Emili et al, 2014), which is an extension of the MOCAGE-PALM system (e.g. El Amraoui et al, 2008a, b) initially developed in the framework of the , 1991).…”

Section: Mocage Ctm and Data Assimilation Systemmentioning

confidence: 99%

Tropospheric CO vertical profiles deduced from total columns using data assimilation: methodology and validation

Amraoui¹,

Attié²,

Ricaud³

et al. 2014

Atmos. Meas. Tech.

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Abstract. This paper presents a validation of a method to derive the vertical profile of carbon monoxide (CO) from its total column using data assimilation. We choose version 3 of MOPITT CO total columns to validate the proposed method. MOPITT products have the advantage of providing both the vertical profiles and the total columns of CO. Furthermore, this version has been extensively validated by comparison with many independent data sets, and has been used in many scientific studies.The first step of the paper consists in the specification of the observation errors based on the chi-square (χ 2 ) test. The observations have been binned according to three types: over land during daytime, over land during night-time, and over sea. Their respective errors using the χ 2 metric have been found to be 8, 11 and 7 %.In the second step, the CO total columns, with their specified errors, are used within the assimilation system to estimate the vertical profiles. These are compared to the retrieved profiles of MOPITT V3 at global and regional scales. Generally, the two data sets show similar patterns and good agreement at both scales. Nevertheless, total column analyses slightly overestimate CO concentrations compared to MO-PITT observations. The mean bias between both data sets is +15 and +12 % at 700 and 250 hPa, respectively.In the third step, the assimilation of total column has been compared to the assimilation of MOPITT vertical profiles. The differences between both analyses are very small. In terms longitude-latitude maps, the mean bias between the two data sets is +6 and +8 % at the pressure levels 700 and 200 hPa, respectively. In terms of zonal means, the CO distribution is similar for both analyses, with a mean bias which does not exceed 12 %.Finally, the two analyses have been validated using independent observations from the aircraft-based MOZAIC program in terms of vertical profiles over eight airports. Over most airports, both analyses agree well with aircraft profiles. For more than 50 % of recorded measurements, the difference between the analyses and MOZAIC does not exceed 5 ppbv (parts per billion by volume).

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Combined assimilation of IASI and MLS observations to constrain tropospheric and stratospheric ozone in a global chemical transport model

Cited by 44 publications

References 71 publications

Impact of spaceborne carbon monoxide observations from the S-5P platform on tropospheric composition analyses and forecasts

Impact of spaceborne carbon monoxide observations from the S-5P platform on tropospheric composition analyses and forecasts

Potential of multispectral synergism for observing ozone pollution by combining IASI-NG and UVNS measurements from the EPS-SG satellite

Tropospheric CO vertical profiles deduced from total columns using data assimilation: methodology and validation

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