MAX-DOAS measurements of formaldehyde in the Po-Valley

Heckel, A.; Richter, Andreas; Tarsu, T.; Wittrock, F.; Hak, Claudia; Pundt, I.; Junkermann, W.; Burrows, John P.

doi:10.5194/acpd-4-1151-2004

Cited by 32 publications

(45 citation statements)

References 5 publications

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“…Therefore the numerical effort is much smaller than for the aerosol retrieval. As already described by Heckel et al [2005] and Sinreich et al [2005], the interpretation of MAX‐DOAS measurements can be performed in a self‐consistent way: In a first step, properties of atmospheric aerosols based on measurements of O 4 and intensity index are retrieved, which then serve as input for the inverse modeling of the vertical distribution of atmospheric trace gases.…”

Section: Discussionmentioning

confidence: 99%

MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

et al. 2006

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[1] A new retrieval algorithm for the determination of aerosol properties using MultiAXis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements based on nonlinear optimal estimation is presented. Using simulated MAX-DOAS measurements of the optical depth of the collision complex of oxygen (O 4 ) as well as the variation of the intensity of diffuse skylight measured at different viewing directions and wavelengths, the capability of this measurement technique to derive the aerosol extinction profile as well as information on the phase function and single scattering albedo is demonstrated. The information content, vertical resolution and retrieval errors under various atmospheric conditions are discussed. Furthermore, it is demonstrated that the assumption of a smooth variation of the aerosol properties between successive measurements can be used to improve the quality of the retrieval by applying a Kalman smoother. The results of these model studies suggest that the achievable precision of MAX-DOAS measurements of the aerosol total optical depth is better than 0.01 and thus comparable with established methods of aerosol detection by Sun photometers (e.g., within the AERONET network) over a wide range of atmospheric conditions. Moreover, MAX-DOAS measurements contain information on the vertical profile of the aerosol extinction, and can be performed with relatively simple, robust and self-calibrating instruments.

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Section: Discussionmentioning

confidence: 99%

MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

et al. 2006

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“…The averages of the measured column amounts at our location are 315 and 1.2 DU for O 3 and SO 2 , respectively. At our site we estimate a maximum amount of total formaldehyde (HCHO) of 2 DU [ Heckel et al , 2005], and we estimate the bromine oxide (BrO) amount not to exceed 0.004 DU [ Leser et al , 2003]. The oxygen dimer (O 2 ‐O 2 ) optical depth in Figure 1 is for 1 atm pressure.…”

Section: Methodsmentioning

confidence: 99%

Measurements of nitrogen dioxide total column amounts using a Brewer double spectrophotometer in direct Sun mode

Cede¹,

Herman²,

Richter³

et al. 2006

J. Geophys. Res.

104

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[1] NO 2 column amounts were measured for the past 2 years at Goddard Space Flight Center, Greenbelt, Maryland, using a Brewer spectrometer in direct Sun mode. A new ''bootstrap'' method to calibrate the instrument is introduced and described. This technique selects the cleanest days from the database to obtain the solar reference spectrum. The main advantage for direct Sun measurements is that the conversion uncertainty from slant column to vertical column is negligible compared to the standard scattered light observations where it is typically on the order of 100% (2s) at polluted sites. The total 2s errors of the direct Sun retrieved column amounts decrease with solar zenith angle and are estimated at 0.2 to 0.6 Dobson units (DU, 1 DU % 2.7 Â 10 16 molecules cm À2 ), which is more accurate than scattered light measurements for high NO 2 amounts. Measured NO 2 column amounts, ranging from 0 to 3 DU with a mean of 0.7 DU, show a pronounced daily course and a strong variability from day to day. The NO 2 concentration typically increases from sunrise to noon. In the afternoon it decreases in summer and stays constant in winter. As expected from the anthropogenic nature of its source, NO 2 amounts on weekends are significantly reduced. The measurements were compared to satellite retrievals from Scanning Image Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY). Satellite data give the same average NO 2 column and show a seasonal cycle that is similar to the ground data in the afternoon. We show that NO 2 must be considered when retrieving aerosol absorption properties, especially for situations with low aerosol optical depth.Citation: Cede, A., J. Herman, A. Richter, N. Krotkov, and J. Burrows (2006), Measurements of nitrogen dioxide total column amounts using a Brewer double spectrophotometer in direct Sun mode,

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“…Almost simultaneous measurements at different viewing angles for the same solar zenith angle from the MAXDOAS instruments have been used to obtain both an accurate tropospheric column for the absorbing trace gas and profile information [ Heckel et al , 2005; Wittrock et al , 2004]. The latter is used as input for the calculation of AMF for the satellite retrieval.…”

Section: Data Retrievalmentioning

confidence: 99%

Simultaneous global observations of glyoxal and formaldehyde from space

Wittrock

Richter

Oetjen

et al. 2006

Geophysical Research Letters

314

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[1] The first global simultaneous observations of glyoxal (CHOCHO) and formaldehyde (HCHO) columns retrieved from measurements by the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) satellite instrument are presented and compared to model calculations. The global pattern of the distribution of CHOCHO is similar to that of HCHO. High values are observed over areas with large biogenic isoprene emissions (Central Africa, parts of South America, and Indonesia). Also regions with biomass burning and anthropogenic pollution exhibit elevated levels of CHOCHO. The ratio of the columns of CHOCHO to HCHO is generally of the order of 0.05 in regions having biogenic emissions, which is in reasonable agreement with the current understanding of the oxidation of hydrocarbons emitted by the biosphere. However and in contrast to our model, high values of both HCHO and CHOCHO are also observed over areas of the tropical oceans. This is tentatively attributed to outflow from the continents and local oceanic biogenic sources of the precursors of HCHO and CHOCHO.

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MAX-DOAS measurements of formaldehyde in the Po-Valley

Cited by 32 publications

References 5 publications

MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

Measurements of nitrogen dioxide total column amounts using a Brewer double spectrophotometer in direct Sun mode

Simultaneous global observations of glyoxal and formaldehyde from space

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MAX-DOAS measurements of formaldehyde in the Po-Valley

Cited by 32 publications

References 5 publications

MAX‐DOAS O4 measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

MAX‐DOAS O4 measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

Measurements of nitrogen dioxide total column amounts using a Brewer double spectrophotometer in direct Sun mode

Simultaneous global observations of glyoxal and formaldehyde from space

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Product

Resources

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MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies

MAX‐DOAS O₄ measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies